CamelCase
Encyclopedia
CamelCase also known as medial capitals, is the practice of writing compound words or phrases in which the elements are joined without space
s, with each element's initial letter capitalized
within the compound and the first letter either upper or lower case—as in "LaBelle
", "BackColor", "McDonald's
", "iPod
", or "GaGa
". The name comes from the uppercase "bumps" in the middle of the compound word, suggestive of the humps of a camel
. The practice is known by many other names.
An early systematic use of medial capitals is the standard notation for chemical formula
e, such as NaCl
, that has been widely used since the 19th century. In the 1970s, medial capitals became an alternative (and often standard) identifier naming convention
for several programming language
s. Since the 1980s, following the popularization of computer technology, it has become fashionable in marketing
for names of products and companies, and for 1990s online video games where players use pseudonym
s (when spaces were not allowed). However, medial capitals are rarely used in formal written English and most style guide
s recommend against their use.
StudlyCaps
style is similar (but not necessarily identical) to camel case. It is sometimes used in reference to camel case but can also refer to random mixed capitalization (as in "MiXeD CaPitALiZaTioN"), popularly used in online culture
.
Camel case is also distinct from title case, which is traditionally used for book titles and headlines. Title case capitalizes most of the words yet retains the spaces between the words.
Camel case is also distinct from Tall Man lettering
, which uses capitals to emphasize the differences between similar-looking words.
(from Scottish
'son of Gillean') and FitzGerald
(from Hiberno-Norman
'son of Gerald'); especially for surnames which include non-English prepositions or other particles, such as DuPont
(from French
'du Pont' or 'Dupont'), DiCaprio
(from Italian
'di Caprio') and VanDyke
(from Dutch
'van Dijk'). The actress ZaSu Pitts
, whose fame peaked in the 1930s and 1940s, sometimes spelled her given name
in camel case, emphasizing its derivation from two other names.
in 1813. To replace the multitude of naming and symbol conventions used by chemists until that time, he proposed to indicate each chemical element by a symbol of one or two letters, the first one being capitalized. The capitalization allowed formulae like 'NaCl' to be written without spaces and still be parsed without ambiguity.
Berzelius's system remains in use to this day, augmented with three-letter symbols like 'Uuq' for unnamed elements; and has been extended to describe the aminoacid sequences of protein
s and other similar domains. Internal capitalization has also been used for other technical codes like HeLa
(1983).
, first published in 1906, H. W. Fowler
and F. G. Fowler
suggested that medial capitals could be used in triple compound words where hyphen
s would cause ambiguity—the examples they give are "KingMark-like" (as against "King Mark-like") and "Anglo-SouthAmerican" (as against "Anglo-South American"). However, they described the system as "too hopelessly contrary to usage at present."
names and product trademark
s, such as
s in several programming language
s. The origin of this convention has not yet been settled. However a 1954 conference proceedings informally referred to IBM's Speedcoding
system as "SpeedCo". Christopher Strachey's paper on GPM
(1965), shows a program that includes some medial capital identifiers, including "NextCh" and "WriteSymbol".
often need to write descriptive (hence multi-word) identifier
s, like "end of file" or "char table", in order to improve the readability of their code. However, most popular programming languages forbid the use of spaces inside identifiers, since they are interpreted as delimiter
s between tokens
. The alternative of writing the words together as in "endoffile" or "chartable" is not satisfactory, since the word boundaries may be quite difficult to discern in the result.
Some early programming languages, notably Lisp (1958) and COBOL
(1959), addressed this problem by allowing a hyphen
("-") to be used between words of compound identifiers, as in "END-OF-FILE". However, this solution was not adequate for algebraic-oriented languages such as FORTRAN
(1955) and ALGOL
(1958), which used the hyphen as an intuitively-obvious subtraction operator. (FORTRAN also restricted identifiers to six characters or fewer at the time, preventing multi-word identifiers except those made of very short words.) Since the common punched card
character sets of the time had no lower-case letters and no other special character that would be adequate for the purpose, those early languages had to do without multi-word identifiers.
It was only in the late 1960s that the widespread adoption of the ASCII
character set made both lower case and the underscore
character "_" universally available. Some languages, notably C
, promptly adopted underscores as word separators; and underscore-separated compounds like "end_of_file" are still prevalent in C programs and libraries. However, some languages and programmers chose to avoid underscores, among other reasons to prevent confusing them with whitespace, and adopted camel case instead. Two accounts are commonly given for the origin of this convention.
The underscore key is inconveniently placed on American QWERTY
keyboards. Additionally, in some fonts the underscore character can be confused with a minus sign; it can be overlooked because it falls below the string of characters or it can be lost entirely when displayed or printed underlined or when printed on a dot-matrix printer with a defective pin or misaligned ribbon. Moreover, early compilers severely restricted the length of identifiers (e.g., to 8 or 14 letters) or silently truncated all identifiers to that length. Finally, the small size of computer display
s available in the 1970s encouraged the use of short identifiers. Many C programmers opted to use camel case instead of underscores, for it yielded legible compound names with fewer keystrokes and fewer characters.
In addition, many C compilers reserve the use of single or double leading underscores for reserved words, compiler directives, or to indicate visibility, e.g. _somePrivateVariable or __HASSOMELIBRARY. While this usage would not rule out medial underscores, avoiding them can give the resulting code greater readability.
around 1978, with the Mesa programming language
developed for the Xerox Alto
computer. This machine lacked an underscore key and the hyphen and space characters were not permitted in identifiers, leaving camel case as the only viable scheme for readable multiword names. The PARC Mesa Language Manual (1979) included a coding standard with specific rules for Upper- and lowerCamelCase which was strictly followed by the Mesa libraries and the Alto operating system.
The Smalltalk
language, which was developed originally on the Alto and became quite popular in the early 1980s, may have been instrumental in spreading the style outside PARC. Camel case was also used by convention for many names in the PostScript
page description language (invented by Adobe Systems
founder and ex-PARC scientist John Warnock
), as well as for the language itself. A further boost was provided by Niklaus Wirth
(the inventor of Pascal
) who acquired a taste for camel case during a sabbatical at PARC and used it in Modula
, his next programming language.
exposed hacker culture to the world. Camel case then became fashion
able for corporate trade name
s, first in computer-related fields but later expanding further into the mainstream. Examples ranging from the 1970s to the 2000s give a history of the spread of the usage:
During the dot-com bubble
of the late 1990s, the lowercase prefixes "e" (for "electronic
") and "i" (for "Internet
", "information
", "intelligent", etc.) became quite common, giving rise to some camel case names like Apple's iMac
and the eBox software platform.
In 1998, Dave Yost suggested that chemists use medial capitals to aid readability of long chemical names, e.g. write AmidoPhosphoRibosylTransferase instead of amidophosphoribosyltransferase
.
This practice is sometimes given to the abbreviated names of certain neighborhoods, particularly New York City neighborhoods, such as SoHo (South of Houston Street) and TriBeCa (Triangle Below Canal Street). Camel case is not always used and the neighborhoods are instead rendered as Soho and Tribeca.
, grammar
s and the Oxford English Dictionary
, was "medial capitals". The fancier names such as "InterCaps", "CamelCase" and variations thereof are relatively recent and seem more common in computer-related communities.
The earliest known occurrence of the term "InterCaps" on Usenet is in an April 1990 post to the group alt.folklore.computers by Avi Rappoport, with "BiCapitalization" appearing slightly later in a 1991 post by Eric S. Raymond
to the same group. The earliest use of the name "CamelCase" occurs in 1995, in a post by Newton Love. "With the advent of programming languages having these sorts of constructs, the humpiness of the style made me call it HumpyCase at first, before I settled on CamelCase. I had been calling it CamelCase for years," said Love, "The citation above was just the first time I had used the name on USENET."
The name "CamelCase" is not related to the "Camel Book" (Programming Perl
), which uses all-lowercase identifiers with underscore
s in its sample code.
, Modula
, Java
, Google SOC
's Python
recommendations, and Microsoft
's .NET) this practice is recommended by the language developers or by authoritative manuals and has therefore become part of the language's "culture". (Note that Google's SOC is a project rather than a language - the use of camel case is not standardised by the Python language and much Python code makes use of underscores to delimit variable names).
Style guidelines often distinguish between upper and lower camel case, typically specifying which variety should be used for specific kinds of entities: variables, record fields
, method
s, procedures, types, etc. These rules are sometimes supported by static analysis
tools that check source code for adherence.
The original Hungarian notation
for programming, for example, specifies that a lowercase abbreviation for the "usage type" (not data type) should prefix all variable names, with the remainder of the name in upper camel case; as such it is a form of lower camel case.
Programming identifiers often need to contain acronyms and initialisms which are already in upper case, such as "old HTML file". By analogy with the title case rules, the natural camel case rendering would have the abbreviation all in upper case, namely "oldHTMLFile". However, this approach is problematic when two acronyms occur together (e.g., "parse DBM XML" would become "parseDBMXML") or when the standard mandates lower camel case but the name begins with an abbreviation (e.g. "SQL server" would become "sQLServer"). For this reason, some programmers prefer to treat abbreviations as if they were lower case words and write "oldHtmlFile", "parseDbmXml" or "sqlServer".
for terms that should be automatically linked to other wiki
pages. This convention was originally used in Ward Cunningham
's original wiki software
, the WikiWikiWeb
and is still used by some other wikis, such as FosWiki, JSPWiki
, TiddlyWiki
, Trac
and PMWiki
. Wikipedia
formerly used camel case linking as well, but switched to explicit link markup using square brackets and many other wiki sites have done the same. Some wikis which use a different link markup by default have an option (sometimes with a plugin) to enable camel case links. Some wikis which do not use camel case linking may still use the camel case as a naming convention, such as AboutUs.
registry requires that XML
data elements use upper camel case and XML attributes use lower camel case.
Most popular command-line interfaces
and scripting
languages cannot easily handle file names that contain embedded spaces (usually requiring the name to be put in quotes). Therefore, users of those systems often resort to camel case (or underscores, hyphens and other "safe" characters) for compound file names like MyJobResume.pdf.
for a variety of purposes, including the ones below:
proper names like rLobsang: the "r" here stands for a prefix glyph in the original script that functions as tone
marker rather than a normal letter. Another example is tsIurku, a Latin transcription of the Chechen
term for the capping stone of the characteristic Medieval defensive towers
of Chechenia and Ingushetia
; the capital letter "I" here denoting a phoneme
distinct from the one transcribed as "i".
This convention is used in Irish orthography
as well as Scots Gaelic orthography
; e.g., ("in Galway
"), from ("Galway"); ("the Scottish person
"), from ("Scottish person"); ("to Ireland
"), from ("Ireland).
Similarly, in transliteration of the Hebrew language
, haIvrit means "the Hebrew person" and biYerushalayim means "in Jerusalem".
This convention is also used by several Bantu languages
(e.g., kiSwahili = "Swahili language
", isiZulu = "Zulu language
") and several indigenous languages of Mexico
(e.g. Nahuatl, Totonacan
, Mixe–Zoque and some Oto-Manguean
languages).
or BSc
.
In French
, camel case acronyms such as OuLiPo
(1960) were favored for a time as alternatives to initialisms.
Camel case is often used to transliterate initialisms into alphabets where two letters may be required to represent a single character of the original alphabet, e.g., DShK
from Cyrillic ДШК.
s and possessive
s may be capitalized to indicate respect, e.g., when referring to the reader of a formal letter or to God
. In some of those languages, the capitalization is customarily retained even when those words occur within compound words or suffixed to a verb. For example, in Italian
one would write ("offering to You respectful salutations") or ("adore Him").
, all nouns carry a grammatical gender
—which, for roles or job titles, is usually masculine. Since the feminist movement
of the 1980s, some writers and publishers have been using the feminine title suffixes -in (singular
) and -innen (plural) to emphasize the inclusion of females; but written with a capital 'I', to indicate that males are not excluded. Example: ("co-workers,male or female") instead of ("co-workers", masculine grammatical gender) or ("female co-workers"). This use is analogous to the use of parentheses in English, for example in the phrase "congress(wo)man."
In German, the names to statutes are also abbreviated using embedded capitals, e.g. StGB (Strafgesetzbuch) for criminal code and PatG (Patentgesetz) for Patent Act.
Whitespace (computer science)
In computer science, whitespace is any single character or series of characters that represents horizontal or vertical space in typography. When rendered, a whitespace character does not correspond to a visual mark, but typically does occupy an area on a page...
s, with each element's initial letter capitalized
Capitalization
Capitalization is writing a word with its first letter as a majuscule and the remaining letters in minuscules . This of course only applies to those writing systems which have a case distinction...
within the compound and the first letter either upper or lower case—as in "LaBelle
Patti LaBelle
Patricia Louise Holte-Edwards , better known under the stage name, Patti LaBelle, is a Grammy Award winning American singer, author and actress who has spent over 50 years in the music industry...
", "BackColor", "McDonald's
McDonald's
McDonald's Corporation is the world's largest chain of hamburger fast food restaurants, serving around 64 million customers daily in 119 countries. Headquartered in the United States, the company began in 1940 as a barbecue restaurant operated by the eponymous Richard and Maurice McDonald; in 1948...
", "iPod
IPod
iPod is a line of portable media players created and marketed by Apple Inc. The product line-up currently consists of the hard drive-based iPod Classic, the touchscreen iPod Touch, the compact iPod Nano, and the ultra-compact iPod Shuffle...
", or "GaGa
Lady GaGa
Stefani Joanne Angelina Germanotta , better known by her stage name Lady Gaga, is an American singer and songwriter. Born and raised in New York City, she primarily studied at the Convent of the Sacred Heart and briefly attended New York University's Tisch School of the Arts before withdrawing to...
". The name comes from the uppercase "bumps" in the middle of the compound word, suggestive of the humps of a camel
Camel
A camel is an even-toed ungulate within the genus Camelus, bearing distinctive fatty deposits known as humps on its back. There are two species of camels: the dromedary or Arabian camel has a single hump, and the bactrian has two humps. Dromedaries are native to the dry desert areas of West Asia,...
. The practice is known by many other names.
An early systematic use of medial capitals is the standard notation for chemical formula
Chemical formula
A chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....
e, such as NaCl
Sodium chloride
Sodium chloride, also known as salt, common salt, table salt or halite, is an inorganic compound with the formula NaCl. Sodium chloride is the salt most responsible for the salinity of the ocean and of the extracellular fluid of many multicellular organisms...
, that has been widely used since the 19th century. In the 1970s, medial capitals became an alternative (and often standard) identifier naming convention
Naming conventions (programming)
In computer programming, a naming convention is a set of rules for choosing the character sequence to be used for identifiers which denote variables, types and functions etc...
for several programming language
Programming language
A programming language is an artificial language designed to communicate instructions to a machine, particularly a computer. Programming languages can be used to create programs that control the behavior of a machine and/or to express algorithms precisely....
s. Since the 1980s, following the popularization of computer technology, it has become fashionable in marketing
Marketing
Marketing is the process used to determine what products or services may be of interest to customers, and the strategy to use in sales, communications and business development. It generates the strategy that underlies sales techniques, business communication, and business developments...
for names of products and companies, and for 1990s online video games where players use pseudonym
Pseudonym
A pseudonym is a name that a person assumes for a particular purpose and that differs from his or her original orthonym...
s (when spaces were not allowed). However, medial capitals are rarely used in formal written English and most style guide
Style guide
A style guide or style manual is a set of standards for the writing and design of documents, either for general use or for a specific publication, organization or field...
s recommend against their use.
Variations and synonyms
The first letter of a camel case compound may or may not be capitalized. For clarity, this article calls the two alternatives upper camel case and lower camel case. Some people and organizations use the term camel case only for lower camel case. Other synonyms include:- BumpyCaps or BumpyCase
- camelBack (or camel-back) notation
- CamelCaps
- CapitalizedWords or CapWords for upper camel case in PythonPython (programming language)Python is a general-purpose, high-level programming language whose design philosophy emphasizes code readability. Python claims to "[combine] remarkable power with very clear syntax", and its standard library is large and comprehensive...
- compoundNames
- Embedded Caps (or Embedded Capitals)
- HumpBack (or hump-back) notation
- InterCaps or intercapping (abbreviation of Internal Capitalization)
- mixedCase for lower camel case in Python
- nerdCaps or headlessCamelCase
- PascalPascal (programming language)Pascal is an influential imperative and procedural programming language, designed in 1968/9 and published in 1970 by Niklaus Wirth as a small and efficient language intended to encourage good programming practices using structured programming and data structuring.A derivative known as Object Pascal...
case for upper camel case - SmalltalkSmalltalkSmalltalk is an object-oriented, dynamically typed, reflective programming language. Smalltalk was created as the language to underpin the "new world" of computing exemplified by "human–computer symbiosis." It was designed and created in part for educational use, more so for constructionist...
case - WikiWord or WikiCase (especially in older wikiWikiA wiki is a website that allows the creation and editing of any number of interlinked web pages via a web browser using a simplified markup language or a WYSIWYG text editor. Wikis are typically powered by wiki software and are often used collaboratively by multiple users. Examples include...
s)
StudlyCaps
StudlyCaps
StudlyCaps is a variation of CamelCase in which the individual letters in a word are capitalized and not capitalized, either at random or in some pattern.-History:...
style is similar (but not necessarily identical) to camel case. It is sometimes used in reference to camel case but can also refer to random mixed capitalization (as in "MiXeD CaPitALiZaTioN"), popularly used in online culture
Leet
Leet , also known as eleet or leetspeak, is an alternative alphabet for the English language that is used primarily on the Internet. It uses various combinations of ASCII characters to replace Latinate letters...
.
Camel case is also distinct from title case, which is traditionally used for book titles and headlines. Title case capitalizes most of the words yet retains the spaces between the words.
Camel case is also distinct from Tall Man lettering
Tall Man lettering
Tall Man lettering is the practice of writing part of a drug's name in upper case letters to help distinguish sound-alike, look-alike drugs from one another in order to avoid medication errors. For example, in Tall Man lettering, "prednisone" and "prednisolone" should be written "predniSONE" and...
, which uses capitals to emphasize the differences between similar-looking words.
Early uses in personal names
Medial capitals have always been used (albeit sporadically) in English, as a spelling style for compound surnames, such as MacLeanClan MacLean
Clan Maclean is a Highland Scottish clan. They are one of the oldest clans in the Highlands and owned large tracts of land in Argyll as well as the Inner Hebrides. Many early MacLeans became famous for their honour, strength and courage in battle. They were involved in many clan skirmishes with...
(from Scottish
Scotland
Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...
'son of Gillean') and FitzGerald
FitzGerald
The surname FitzGerald is a translation of the French-Norman fils de Gérald, or son of Gerald . Variant spellings include Fitz-Gerald and the modern Fitzgerald. The name can also be used as two separate words Fitz Gerald...
(from Hiberno-Norman
Hiberno-Norman
The Hiberno-Normans are those Norman lords who settled in Ireland who admitted little if any real fealty to the Anglo-Norman settlers in England, and who soon began to interact and intermarry with the Gaelic nobility of Ireland. The term embraces both their origins as a distinct community with...
'son of Gerald'); especially for surnames which include non-English prepositions or other particles, such as DuPont
DuPont
E. I. du Pont de Nemours and Company , commonly referred to as DuPont, is an American chemical company that was founded in July 1802 as a gunpowder mill by Eleuthère Irénée du Pont. DuPont was the world's third largest chemical company based on market capitalization and ninth based on revenue in 2009...
(from French
French language
French is a Romance language spoken as a first language in France, the Romandy region in Switzerland, Wallonia and Brussels in Belgium, Monaco, the regions of Quebec and Acadia in Canada, and by various communities elsewhere. Second-language speakers of French are distributed throughout many parts...
'du Pont' or 'Dupont'), DiCaprio
Leonardo DiCaprio
Leonardo Wilhelm DiCaprio is an American actor and film producer. He has received many awards, including a Golden Globe Award for Best Actor for his performance in The Aviator , and has been nominated by the Academy Awards, Screen Actors Guild and the British Academy of Film and Television...
(from Italian
Italian language
Italian is a Romance language spoken mainly in Europe: Italy, Switzerland, San Marino, Vatican City, by minorities in Malta, Monaco, Croatia, Slovenia, France, Libya, Eritrea, and Somalia, and by immigrant communities in the Americas and Australia...
'di Caprio') and VanDyke
James A. VanDyke
James Adams Van Dyke was a lawyer, fireman and the 21st mayor of Detroit, Michigan. He was elected in 1847.-Early Biography:...
(from Dutch
Dutch language
Dutch is a West Germanic language and the native language of the majority of the population of the Netherlands, Belgium, and Suriname, the three member states of the Dutch Language Union. Most speakers live in the European Union, where it is a first language for about 23 million and a second...
'van Dijk'). The actress ZaSu Pitts
ZaSu Pitts
ZaSu Pitts was an American actress who starred in many silent dramas and comedies, transitioning to comedy sound films.-Early life:ZaSu Pitts was born in Parsons, Kansas to Rulandus and Nellie Pitts; she was the third of four children...
, whose fame peaked in the 1930s and 1940s, sometimes spelled her given name
Given name
A given name, in Western contexts often referred to as a first name, is a personal name that specifies and differentiates between members of a group of individuals, especially in a family, all of whose members usually share the same family name...
in camel case, emphasizing its derivation from two other names.
Chemical formulae
The first systematic and widespread use of medial capitals for technical purposes was the notation for chemical formulae invented by the Swedish chemist BerzeliusJöns Jakob Berzelius
Jöns Jacob Berzelius was a Swedish chemist. He worked out the modern technique of chemical formula notation, and is together with John Dalton, Antoine Lavoisier, and Robert Boyle considered a father of modern chemistry...
in 1813. To replace the multitude of naming and symbol conventions used by chemists until that time, he proposed to indicate each chemical element by a symbol of one or two letters, the first one being capitalized. The capitalization allowed formulae like 'NaCl' to be written without spaces and still be parsed without ambiguity.
Berzelius's system remains in use to this day, augmented with three-letter symbols like 'Uuq' for unnamed elements; and has been extended to describe the aminoacid sequences of protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
s and other similar domains. Internal capitalization has also been used for other technical codes like HeLa
HeLa
A HeLa cell is a cell type in an immortal cell line used in scientific research. It is the oldest and most commonly used human cell line. The line was derived from cervical cancer cells taken on February 8, 1951 from Henrietta Lacks, a patient who eventually died of her cancer on October 4, 1951...
(1983).
The King's English
In their English style guide The King's EnglishThe King's English
The King's English is a book on English usage and grammar. It was written by the Fowler brothers, Henry Watson Fowler and Francis George Fowler, and published in 1906, and thus pre-dates by 20 years Modern English Usage, which was written by Henry alone after Francis's death in 1918.The King's...
, first published in 1906, H. W. Fowler
Henry Watson Fowler
Henry Watson Fowler was an English schoolmaster, lexicographer and commentator on the usage of the English language...
and F. G. Fowler
Francis George Fowler
Francis George Fowler , familiarly known as F.G. Fowler, was an English writer on English language, grammar and usage.Born in Tunbridge Wells, F. G. Fowler was educated at Peterhouse, Cambridge. He lived on Guernsey in the Channel Islands...
suggested that medial capitals could be used in triple compound words where hyphen
Hyphen
The hyphen is a punctuation mark used to join words and to separate syllables of a single word. The use of hyphens is called hyphenation. The hyphen should not be confused with dashes , which are longer and have different uses, or with the minus sign which is also longer...
s would cause ambiguity—the examples they give are "KingMark-like" (as against "King Mark-like") and "Anglo-SouthAmerican" (as against "Anglo-South American"). However, they described the system as "too hopelessly contrary to usage at present."
Early use in trademarks
Since the mid-20th century, medial capitals have occasionally been used for corporateCorporation
A corporation is created under the laws of a state as a separate legal entity that has privileges and liabilities that are distinct from those of its members. There are many different forms of corporations, most of which are used to conduct business. Early corporations were established by charter...
names and product trademark
Trademark
A trademark, trade mark, or trade-mark is a distinctive sign or indicator used by an individual, business organization, or other legal entity to identify that the products or services to consumers with which the trademark appears originate from a unique source, and to distinguish its products or...
s, such as
- CinemaScopeCinemaScopeCinemaScope was an anamorphic lens series used for shooting wide screen movies from 1953 to 1967. Its creation in 1953, by the president of 20th Century-Fox, marked the beginning of the modern anamorphic format in both principal photography and movie projection.The anamorphic lenses theoretically...
and VistaVisionVistaVisionVistaVision is a higher resolution, widescreen variant of the 35mm motion picture film format which was created by engineers at Paramount Pictures in 1954....
, rival widescreenWidescreenWidescreen images are a variety of aspect ratios used in film, television and computer screens. In film, a widescreen film is any film image with a width-to-height aspect ratio greater than the standard 1.37:1 Academy aspect ratio provided by 35mm film....
movieFilmA film, also called a movie or motion picture, is a series of still or moving images. It is produced by recording photographic images with cameras, or by creating images using animation techniques or visual effects...
formats (1953) - ShopKo (1962)
- MisterRogers, the CanadianCanadaCanada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
version of Mister Rogers' NeighborhoodMister Rogers' NeighborhoodMister Rogers' Neighborhood, also known as Mister Rogers, is an American children's television series that was created and hosted by Fred Rogers. The series is aimed primarily at preschool ages, 2-5, but has been stated by Public Broadcasting Service as "appropriate for all ages"...
(1962) - AstroTurfAstroTurfAstroTurf is a brand of artificial turf. Although the term is a registered trademark, it is sometimes used as a generic description of any kind of artificial turf. The original AstroTurf product was a short pile synthetic turf while the current products incorporate modern features such as...
(1967) - ConAgra, formerly Consolidated Mills (1971).
Computer programming
In the 1970s and 1980s, medial capitals were adopted as a standard or alternative naming convention for multi-word identifierIdentifier
An identifier is a name that identifies either a unique object or a unique class of objects, where the "object" or class may be an idea, physical [countable] object , or physical [noncountable] substance...
s in several programming language
Programming language
A programming language is an artificial language designed to communicate instructions to a machine, particularly a computer. Programming languages can be used to create programs that control the behavior of a machine and/or to express algorithms precisely....
s. The origin of this convention has not yet been settled. However a 1954 conference proceedings informally referred to IBM's Speedcoding
Speedcoding
Speedcoding or Speedcode was the first higher-level language created for an IBM computer. The language was developed by John Backus in 1953 for the IBM 701 to support computation with floating point numbers....
system as "SpeedCo". Christopher Strachey's paper on GPM
GPM
GPM may refer to:*GPM , a mouse server for the console and xterm*Gallons per minute, a unit of volumetric flow rate*Gallons per mile, a unit of fuel efficiency*General Purpose Macrogenerator, an early macro processor...
(1965), shows a program that includes some medial capital identifiers, including "NextCh" and "WriteSymbol".
Background: multi-word identifiers
Computer programmersComputer program
A computer program is a sequence of instructions written to perform a specified task with a computer. A computer requires programs to function, typically executing the program's instructions in a central processor. The program has an executable form that the computer can use directly to execute...
often need to write descriptive (hence multi-word) identifier
Identifier
An identifier is a name that identifies either a unique object or a unique class of objects, where the "object" or class may be an idea, physical [countable] object , or physical [noncountable] substance...
s, like "end of file" or "char table", in order to improve the readability of their code. However, most popular programming languages forbid the use of spaces inside identifiers, since they are interpreted as delimiter
Delimiter
A delimiter is a sequence of one or more characters used to specify the boundary between separate, independent regions in plain text or other data streams. An example of a delimiter is the comma character, which acts as a field delimiter in a sequence of comma-separated values.Delimiters represent...
s between tokens
Lexical analysis
In computer science, lexical analysis is the process of converting a sequence of characters into a sequence of tokens. A program or function which performs lexical analysis is called a lexical analyzer, lexer or scanner...
. The alternative of writing the words together as in "endoffile" or "chartable" is not satisfactory, since the word boundaries may be quite difficult to discern in the result.
Some early programming languages, notably Lisp (1958) and COBOL
COBOL
COBOL is one of the oldest programming languages. Its name is an acronym for COmmon Business-Oriented Language, defining its primary domain in business, finance, and administrative systems for companies and governments....
(1959), addressed this problem by allowing a hyphen
Hyphen
The hyphen is a punctuation mark used to join words and to separate syllables of a single word. The use of hyphens is called hyphenation. The hyphen should not be confused with dashes , which are longer and have different uses, or with the minus sign which is also longer...
("-") to be used between words of compound identifiers, as in "END-OF-FILE". However, this solution was not adequate for algebraic-oriented languages such as FORTRAN
Fortran
Fortran is a general-purpose, procedural, imperative programming language that is especially suited to numeric computation and scientific computing...
(1955) and ALGOL
ALGOL 58
ALGOL 58, originally known as IAL, is one of the family of ALGOL computer programming languages. It was an early compromise design soon superseded by ALGOL 60...
(1958), which used the hyphen as an intuitively-obvious subtraction operator. (FORTRAN also restricted identifiers to six characters or fewer at the time, preventing multi-word identifiers except those made of very short words.) Since the common punched card
Punched card
A punched card, punch card, IBM card, or Hollerith card is a piece of stiff paper that contains digital information represented by the presence or absence of holes in predefined positions...
character sets of the time had no lower-case letters and no other special character that would be adequate for the purpose, those early languages had to do without multi-word identifiers.
It was only in the late 1960s that the widespread adoption of the ASCII
ASCII
The American Standard Code for Information Interchange is a character-encoding scheme based on the ordering of the English alphabet. ASCII codes represent text in computers, communications equipment, and other devices that use text...
character set made both lower case and the underscore
Underscore
The underscore [ _ ] is a character that originally appeared on the typewriter and was primarily used to underline words...
character "_" universally available. Some languages, notably C
C (programming language)
C is a general-purpose computer programming language developed between 1969 and 1973 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system....
, promptly adopted underscores as word separators; and underscore-separated compounds like "end_of_file" are still prevalent in C programs and libraries. However, some languages and programmers chose to avoid underscores, among other reasons to prevent confusing them with whitespace, and adopted camel case instead. Two accounts are commonly given for the origin of this convention.
The "Lazy Programmer" theory
One theory for the origin of the camel case convention holds that C programmers and hackers simply found it more convenient than the standard underscore-based style.The underscore key is inconveniently placed on American QWERTY
QWERTY
QWERTY is the most common modern-day keyboard layout. The name comes from the first six letters appearing in the topleft letter row of the keyboard, read left to right: Q-W-E-R-T-Y. The QWERTY design is based on a layout created for the Sholes and Glidden typewriter and sold to Remington in the...
keyboards. Additionally, in some fonts the underscore character can be confused with a minus sign; it can be overlooked because it falls below the string of characters or it can be lost entirely when displayed or printed underlined or when printed on a dot-matrix printer with a defective pin or misaligned ribbon. Moreover, early compilers severely restricted the length of identifiers (e.g., to 8 or 14 letters) or silently truncated all identifiers to that length. Finally, the small size of computer display
Computer display
A monitor or display is an electronic visual display for computers. The monitor comprises the display device, circuitry, and an enclosure...
s available in the 1970s encouraged the use of short identifiers. Many C programmers opted to use camel case instead of underscores, for it yielded legible compound names with fewer keystrokes and fewer characters.
In addition, many C compilers reserve the use of single or double leading underscores for reserved words, compiler directives, or to indicate visibility, e.g. _somePrivateVariable or __HASSOMELIBRARY. While this usage would not rule out medial underscores, avoiding them can give the resulting code greater readability.
The "Alto Keyboard" theory
Another account claims that the camel case style first became popular at Xerox PARCXerox PARC
PARC , formerly Xerox PARC, is a research and co-development company in Palo Alto, California, with a distinguished reputation for its contributions to information technology and hardware systems....
around 1978, with the Mesa programming language
Mesa programming language
Mesa was an innovative programming language developed in the late 1970s at the Xerox Palo Alto Research Center in Palo Alto, California, United States. The language was named after the mesas of the American Southwest, referring to its design intent to be a "high-level" programming language.Mesa is...
developed for the Xerox Alto
Xerox Alto
The Xerox Alto was one of the first computers designed for individual use , making it arguably what is now called a personal computer. It was developed at Xerox PARC in 1973...
computer. This machine lacked an underscore key and the hyphen and space characters were not permitted in identifiers, leaving camel case as the only viable scheme for readable multiword names. The PARC Mesa Language Manual (1979) included a coding standard with specific rules for Upper- and lowerCamelCase which was strictly followed by the Mesa libraries and the Alto operating system.
The Smalltalk
Smalltalk
Smalltalk is an object-oriented, dynamically typed, reflective programming language. Smalltalk was created as the language to underpin the "new world" of computing exemplified by "human–computer symbiosis." It was designed and created in part for educational use, more so for constructionist...
language, which was developed originally on the Alto and became quite popular in the early 1980s, may have been instrumental in spreading the style outside PARC. Camel case was also used by convention for many names in the PostScript
PostScript
PostScript is a dynamically typed concatenative programming language created by John Warnock and Charles Geschke in 1982. It is best known for its use as a page description language in the electronic and desktop publishing areas. Adobe PostScript 3 is also the worldwide printing and imaging...
page description language (invented by Adobe Systems
Adobe Systems
Adobe Systems Incorporated is an American computer software company founded in 1982 and headquartered in San Jose, California, United States...
founder and ex-PARC scientist John Warnock
John Warnock
John Edward Warnock is an American computer scientist best known as the co-founder with Charles Geschke of Adobe Systems Inc., the graphics and publishing software company. Dr. Warnock was President of Adobe for his first two years and Chairman and CEO for his remaining sixteen years at the company...
), as well as for the language itself. A further boost was provided by Niklaus Wirth
Niklaus Wirth
Niklaus Emil Wirth is a Swiss computer scientist, best known for designing several programming languages, including Pascal, and for pioneering several classic topics in software engineering. In 1984 he won the Turing Award for developing a sequence of innovative computer languages.-Biography:Wirth...
(the inventor of Pascal
Pascal (programming language)
Pascal is an influential imperative and procedural programming language, designed in 1968/9 and published in 1970 by Niklaus Wirth as a small and efficient language intended to encourage good programming practices using structured programming and data structuring.A derivative known as Object Pascal...
) who acquired a taste for camel case during a sabbatical at PARC and used it in Modula
Modula
The Modula programming language is a descendent of the Pascal programming language. It was developed in Switzerland in the late 1970s by Niklaus Wirth, the same person who designed Pascal...
, his next programming language.
Spread to mainstream usage
Whatever its origins within the computing world, camel case spread to a wider audience in the 1980s and 1990s, when the advent of the personal computerPersonal computer
A personal computer is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end-user with no intervening computer operator...
exposed hacker culture to the world. Camel case then became fashion
Fashion
Fashion, a general term for a currently popular style or practice, especially in clothing, foot wear, or accessories. Fashion references to anything that is the current trend in look and dress up of a person...
able for corporate trade name
Trade name
A trade name, also known as a trading name or a business name, is the name which a business trades under for commercial purposes, although its registered, legal name, used for contracts and other formal situations, may be another....
s, first in computer-related fields but later expanding further into the mainstream. Examples ranging from the 1970s to the 2000s give a history of the spread of the usage:
- (1971) AeroVironmentAeroVironmentAeroVironment Inc. is a technology company in Monrovia, California, and Simi Valley, California, that is primarily involved in energy systems, electric vehicle systems, and unmanned aerial vehicles . Paul B. MacCready, Jr., a famous designer of human powered aircraft, founded the company in 1971...
- (1977) CompuServeCompuServeCompuServe was the first major commercial online service in the United States. It dominated the field during the 1980s and remained a major player through the mid-1990s, when it was sidelined by the rise of services such as AOL with monthly subscriptions rather than hourly rates...
, UnitedHealthCareUnitedHealth GroupUnitedHealth Group Incorporated is a diversified health and "well-being" company. Headquartered in Minnetonka, Minnesota, UnitedHealth Group offers a spectrum of products and services through two operating businesses: United Healthcare and Optum. Through its family of subsidiaries and divisions,...
(now UnitedHealthcare). - (1979) MasterCardMasterCardMastercard Incorporated or MasterCard Worldwide is an American multinational financial services corporation with its headquarters in the MasterCard International Global Headquarters, Purchase, Harrison, New York, United States...
, SportsCenterSportsCenterSportsCenter is a daily sports news television show, and the flagship program of American cable network ESPN since the network launched on September 7, 1979. Originally broadcast only daily, SportsCenter is now shown up to twelve times a day, replaying the day's scores and highlights from major...
, VisiCalcVisiCalcVisiCalc was the first spreadsheet program available for personal computers. It is often considered the application that turned the microcomputer from a hobby for computer enthusiasts into a serious business tool... - (1980) EchoStar
- (1982) MicroProseMicroProseMicroProse was a video game publisher and developer, founded by Wild Bill Stealey and Sid Meier in 1982 as Microprose Software. In 1993, the company became a subsidiary of Spectrum HoloByte and has remained a subsidiary or brand name under several other corporations since...
, WordPerfectWordPerfectWordPerfect is a word processing application, now owned by Corel.Bruce Bastian, a Brigham Young University graduate student, and BYU computer science professor Dr. Alan Ashton joined forces to design a word processing system for the city of Orem's Data General Corp. minicomputer system in 1979... - (1983) NetWareNovell NetWareNetWare is a network operating system developed by Novell, Inc. It initially used cooperative multitasking to run various services on a personal computer, with network protocols based on the archetypal Xerox Network Systems stack....
- (1984) BellSouthBellSouthBellSouth Corporation is an American telecommunications holding company based in Atlanta, Georgia. BellSouth was one of the seven original Regional Bell Operating Companies after the U.S...
, LaserJetLaserJetLaserJet as a brand name identifies the line of dry electrophotographic laser printers marketed by the American computer-company Hewlett-Packard . The HP LaserJet was the world's first desktop laser printer.-Technology:...
, MacWorks, iDENIdenFor other uses of the word, see Iden The Iden was an English automobile manufactured from 1904 until 1907. Designed by George Iden, formerly of Daimler, they were four-cylinder 10/17 hp and 25/35 hp shaft-driven cars; each came with "Idens's frictionless radial gearbox".... - (1985) PageMakerAdobe PageMakerPageMaker was one of the first desktop publishing programs, introduced in 1985 by Aldus Corporation, initially for the then-new Apple Macintosh and in 1987 for PCs running Windows 1.0....
, EastEndersEastEndersEastEnders is a British television soap opera, first broadcast in the United Kingdom on BBC One on 19 February 1985 and continuing to today. EastEnders storylines examine the domestic and professional lives of the people who live and work in the fictional London Borough of Walford in the East End... - (1986) SpaceCampSpaceCampSpaceCamp is a 1986 American film based on a book by Patrick Bailey and Larry B. Williams and inspired by the U.S. Space Camp in Huntsville, Alabama. Directed by Harry Winer from a screenplay by Clifford Green and Casey T. Mitchell, the film stars Kate Capshaw, Kelly Preston, Larry B...
- (1987) ClarisWorks, HyperCardHyperCardHyperCard is an application program created by Bill Atkinson for Apple Computer, Inc. that was among the first successful hypermedia systems before the World Wide Web. It combines database capabilities with a graphical, flexible, user-modifiable interface. HyperCard also features HyperTalk, written...
, PowerPoint - (1990) HarperCollins, SeaTacSeaTac, WashingtonSeaTac is an American city in southern King County, Washington, and an outlying suburb of Seattle, Washington. Incorporated in February 1990, the City of SeaTac is ten square miles in area and has a population of 26,909 according to the 2010 census...
, iconic WorldWideWebWorldWideWebWorldWideWeb, later renamed to Nexus to avoid confusion between the software and the World Wide Web, was the first web browser and editor. When it was written, WorldWideWeb was the only way to view the Web.... - (1991) SuperAmerica, TriStar PicturesTriStar PicturesTriStar Pictures, Inc. is an American film production/distribution studio and subsidiary of Columbia Pictures, itself a subdivision of the Columbia TriStar Motion Picture Group, which is owned by Sony Pictures...
(formerly Tri-Star Pictures) - (1992) OutKastOutKastOutkast is an American hip hop duo based in East Point, Georgia, consisting of Atlanta native André "André 3000" Benjamin and Savannah, Georgia-born Antwan "Big Boi" Patton. They were originally known as Two Shades Deep but later changed the group's name to OutKast...
, ThinkPadThinkPadThinkPad is line of laptop computers originally sold by IBM but now produced by Lenovo. They are known for their boxy black design, which was modeled after a traditional Japanese lunchbox...
, IndyCarIndyCar SeriesThe IZOD IndyCar Series is the premier level of American open wheel racing. The current championship, founded by Indianapolis Motor Speedway owner Tony George, began in 1996 as a competitor to CART known as the Indy Racing League . Citing CART's increasing reliance on expensive machinery and... - (1993) AmeriCorpsAmeriCorpsAmeriCorps is a U.S. federal government program that was created under President Bill Clinton by the National and Community Service Trust Act of 1993 and later expanded by 50 percent under President George W. Bush...
, EcoParkBirmingham EcoParkThe Birmingham EcoPark is an environmental education centre in the Small Heath area of Birmingham, England, operated by the Wildlife Trust for Birmingham and the Black Country. It is a wildlife gardening demonstration garden. It has displays of sustainable energy, recycling and gardening with...
, ValuJet (now AirTran AirwaysAirTran AirwaysAirTran Airways, a subsidiary of the Dallas, Texas-based Southwest Airlines, is an American low-cost airline headquartered in Orlando, Florida. AirTran operates over 650 daily flights , primarily in the eastern and midwestern United States...
), SolidWorksSolidWorksSolidWorks is a 3D mechanical CAD program that runs on Microsoft Windows and is being developed by Dassault Systèmes SolidWorks Corp., a subsidiary of Dassault Systèmes, S. A. . SolidWorks is currently used by over 1.3 million engineers and designers at more than 130,000 companies worldwide... - (1994) FedEx (formerly Federal Express), PlayStationPlayStationThe is a 32-bit fifth-generation video game console first released by Sony Computer Entertainment in Japan on December 3, .The PlayStation was the first of the PlayStation series of consoles and handheld game devices. The PlayStation 2 was the console's successor in 2000...
, easyJetEasyJetEasyJet Airline Company Limited is a British airline headquartered at London Luton Airport. It carries more passengers than any other United Kingdom-based airline, operating domestic and international scheduled services on 500 routes between 118 European, North African, and West Asian airports...
(an early use of camel case with lowercase first letter), DreamWorksDreamWorksDreamWorks Pictures, also known as DreamWorks, LLC, DreamWorks SKG, DreamWorks II Distribution Co., LLC, DreamWorks Studios or DW Studios, LLC, is an American film studio which develops, produces, and distributes films, video games and television programming... - (1995) eBayEBayeBay Inc. is an American internet consumer-to-consumer corporation that manages eBay.com, an online auction and shopping website in which people and businesses buy and sell a broad variety of goods and services worldwide...
, ColdFusionColdFusionIn computing, ColdFusion is the name of a commercial rapid application development platform invented by Jeremy and JJ Allaire in 1995. ColdFusion was originally designed to make it easier to connect simple HTML pages to a database, by version 2 it had... - (1996) RadioShackRadioShackRadioShack Corporation is an American franchise of electronics retail stores in the United States, as well as parts of Europe, South America and Africa. As of 2008, RadioShack reported net sales and operating revenues of $4.81 billion. The headquarters of RadioShack is located in Downtown...
(formerly Radio Shack) - (1997) TiVoTiVoTiVo is a digital video recorder developed and marketed by TiVo, Inc. and introduced in 1999. TiVo provides an on-screen guide of scheduled broadcast programming television programs, whose features include "Season Pass" schedules which record every new episode of a series, and "WishList"...
- (1998) DaimlerChryslerDaimlerChryslerDaimler AG is a German car corporation. By unit sales, it is the thirteenth-largest car manufacturer and second-largest truck manufacturer in the world. In addition to automobiles, Daimler manufactures buses and provides financial services through its Daimler Financial Services arm...
, PricewaterhouseCoopersPricewaterhouseCoopersPricewaterhouseCoopers is a global professional services firm headquartered in London, United Kingdom. It is the world's largest professional services firm measured by revenues and one of the "Big Four" accountancy firms....
, iMacIMacThe iMac is a range of all-in-one Macintosh desktop computers built by Apple. It has been the primary part of Apple's consumer desktop offerings since its introduction in 1998, and has evolved through five distinct forms.... - (1999) BlackBerryBlackBerryBlackBerry is a line of mobile email and smartphone devices developed and designed by Canadian company Research In Motion since 1999.BlackBerry devices are smartphones, designed to function as personal digital assistants, portable media players, internet browsers, gaming devices, and much more...
, DragonForceDragonForceDragonForce are an English power metal band from London. Formed in 1999, the group is known for its long and fast guitar solos, fantasy-based lyrics, and electronic sounds in their music to add to their retro video game-influenced sound. Guitarists Herman Li and Sam Totman are the only two...
, SpongeBob SquarePantsSpongeBob SquarePantsSpongeBob SquarePants is an American animated television series, created by marine biologist and animator Stephen Hillenburg. Much of the series centers on the exploits and adventures of the title character and his various friends in the underwater city of "Bikini Bottom"...
, jetBlueJetBlue AirwaysJetBlue Airways Corporation is an American low-cost airline. The company is headquartered in the Forest Hills neighborhood of the New York City borough of Queens. Its main base is John F. Kennedy International Airport, also in Queens....
, ExxonMobilExxonMobilExxon Mobil Corporation or ExxonMobil, is an American multinational oil and gas corporation. It is a direct descendant of John D. Rockefeller's Standard Oil company, and was formed on November 30, 1999, by the merger of Exxon and Mobil. Its headquarters are in Irving, Texas... - (2000) GlaxoSmithKlineGlaxoSmithKlineGlaxoSmithKline plc is a global pharmaceutical, biologics, vaccines and consumer healthcare company headquartered in London, United Kingdom...
, PayPalPayPalPayPal is an American-based global e-commerce business allowing payments and money transfers to be made through the Internet. Online money transfers serve as electronic alternatives to paying with traditional paper methods, such as checks and money orders.... - (2001) AmerisourceBergen, Nintendo GameCubeNintendo GameCubeThe , officially abbreviated to NGC in Japan and GCN in other regions, is a sixth generation video game console released by Nintendo on September 15, 2001 in Japan, November 18, 2001 in North America, May 3, 2002 in Europe, and May 17, 2002 in Australia...
, ProQuestProQuestProQuest LLC is an Ann Arbor, Michigan-based electronic publisher and microfilm publisher.It provides archives of sources such as newspapers, periodicals, dissertations, and aggregated databases of many types. Its content is estimated at 125 billion digital pages... - (2003) MySpaceMySpaceMyspace is a social networking service owned by Specific Media LLC and pop star Justin Timberlake. Myspace launched in August 2003 and is headquartered in Beverly Hills, California. In August 2011, Myspace had 33.1 million unique U.S. visitors....
, WordPressWordPressWordPress is a free and open source blogging tool and publishing platform powered by PHP and MySQL. It is often customized into a content management system . It has many features including a plug-in architecture and a template system. WordPress is used by over 14.7% of Alexa Internet's "top 1... - (2005) YouTubeYouTubeYouTube is a video-sharing website, created by three former PayPal employees in February 2005, on which users can upload, view and share videos....
, PetSmartPetSmartPetSmart, Inc. is a retail chain doing business in the United States and Canada engaged in the sale of specialty pet supplies and services such as grooming and dog training, PetSmart PetsHotel dog and cat boarding facilities and Doggie Day Care.- History :... - (2006) WikiLeaksWikileaksWikiLeaks is an international self-described not-for-profit organisation that publishes submissions of private, secret, and classified media from anonymous news sources, news leaks, and whistleblowers. Its website, launched in 2006 under The Sunshine Press organisation, claimed a database of more...
- (2007) HealthCorpsHealthCorpsHealthCorps is an American non-profit organization that responds to the obesity crisis through school-based health education and peer-mentoring in addition to community outreach to underserved populations – mostly Hispanic and African-American....
, MillerCoorsMillerCoorsMillerCoors is a joint venture between SABMiller and Molson Coors Brewing Company, announced on October 9, 2007. The joint venture has the responsibility of selling brands such as Miller Lite, Miller High Life, Miller Genuine Draft, Coors, Coors Light, Molson Canadian, and Blue Moon in the United... - (2008) Fort Wayne TinCaps
During the dot-com bubble
Dot-com bubble
The dot-com bubble was a speculative bubble covering roughly 1995–2000 during which stock markets in industrialized nations saw their equity value rise rapidly from growth in the more...
of the late 1990s, the lowercase prefixes "e" (for "electronic
Electronics
Electronics is the branch of science, engineering and technology that deals with electrical circuits involving active electrical components such as vacuum tubes, transistors, diodes and integrated circuits, and associated passive interconnection technologies...
") and "i" (for "Internet
Internet
The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite to serve billions of users worldwide...
", "information
Information
Information in its most restricted technical sense is a message or collection of messages that consists of an ordered sequence of symbols, or it is the meaning that can be interpreted from such a message or collection of messages. Information can be recorded or transmitted. It can be recorded as...
", "intelligent", etc.) became quite common, giving rise to some camel case names like Apple's iMac
IMac
The iMac is a range of all-in-one Macintosh desktop computers built by Apple. It has been the primary part of Apple's consumer desktop offerings since its introduction in 1998, and has evolved through five distinct forms....
and the eBox software platform.
In 1998, Dave Yost suggested that chemists use medial capitals to aid readability of long chemical names, e.g. write AmidoPhosphoRibosylTransferase instead of amidophosphoribosyltransferase
Amidophosphoribosyltransferase
Amidophosphoribosyltransferase , also known as glutamine phosphoribosylpyrophosphate amidotransferase , is an enzyme that in humans is encoded by the PPAT gene.- Function :...
.
This practice is sometimes given to the abbreviated names of certain neighborhoods, particularly New York City neighborhoods, such as SoHo (South of Houston Street) and TriBeCa (Triangle Below Canal Street). Camel case is not always used and the neighborhoods are instead rendered as Soho and Tribeca.
History of the name "camel case"
The original name of the practice, used in media studiesMedia studies
Media studies is an academic discipline and field of study that deals with the content, history and effects of various media; in particular, the 'mass media'. Media studies may draw on traditions from both the social sciences and the humanities, but mostly from its core disciplines of mass...
, grammar
Grammar
In linguistics, grammar is the set of structural rules that govern the composition of clauses, phrases, and words in any given natural language. The term refers also to the study of such rules, and this field includes morphology, syntax, and phonology, often complemented by phonetics, semantics,...
s and the Oxford English Dictionary
Oxford English Dictionary
The Oxford English Dictionary , published by the Oxford University Press, is the self-styled premier dictionary of the English language. Two fully bound print editions of the OED have been published under its current name, in 1928 and 1989. The first edition was published in twelve volumes , and...
, was "medial capitals". The fancier names such as "InterCaps", "CamelCase" and variations thereof are relatively recent and seem more common in computer-related communities.
The earliest known occurrence of the term "InterCaps" on Usenet is in an April 1990 post to the group alt.folklore.computers by Avi Rappoport, with "BiCapitalization" appearing slightly later in a 1991 post by Eric S. Raymond
Eric S. Raymond
Eric Steven Raymond , often referred to as ESR, is an American computer programmer, author and open source software advocate. After the 1997 publication of The Cathedral and the Bazaar, Raymond was for a number of years frequently quoted as an unofficial spokesman for the open source movement...
to the same group. The earliest use of the name "CamelCase" occurs in 1995, in a post by Newton Love. "With the advent of programming languages having these sorts of constructs, the humpiness of the style made me call it HumpyCase at first, before I settled on CamelCase. I had been calling it CamelCase for years," said Love, "The citation above was just the first time I had used the name on USENET."
The name "CamelCase" is not related to the "Camel Book" (Programming Perl
Programming Perl
Programming Perl, ISBN 0-596-00027-8,best known as the Camel Book among programmers, is a book and ebook about writing programs using the Perl programming language, revised as several editions to reflect major language changes since Perl version 4. Editions have been co-written by the creator of...
), which uses all-lowercase identifiers with underscore
Underscore
The underscore [ _ ] is a character that originally appeared on the typewriter and was primarily used to underline words...
s in its sample code.
Programming and coding
The use of medial caps for compound identifiers is recommended by the coding style guidelines of many organizations or software projects. For some languages (such as Mesa, PascalPascal (programming language)
Pascal is an influential imperative and procedural programming language, designed in 1968/9 and published in 1970 by Niklaus Wirth as a small and efficient language intended to encourage good programming practices using structured programming and data structuring.A derivative known as Object Pascal...
, Modula
Modula
The Modula programming language is a descendent of the Pascal programming language. It was developed in Switzerland in the late 1970s by Niklaus Wirth, the same person who designed Pascal...
, Java
Java (programming language)
Java is a programming language originally developed by James Gosling at Sun Microsystems and released in 1995 as a core component of Sun Microsystems' Java platform. The language derives much of its syntax from C and C++ but has a simpler object model and fewer low-level facilities...
, Google SOC
Google Summer of Code
The Google Summer of Code is an annual program, first held from May to August 2005, in which Google awards stipends to hundreds of students who successfully complete a requested free or open-source software coding project during the summer...
's Python
Python (programming language)
Python is a general-purpose, high-level programming language whose design philosophy emphasizes code readability. Python claims to "[combine] remarkable power with very clear syntax", and its standard library is large and comprehensive...
recommendations, and Microsoft
Microsoft
Microsoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...
's .NET) this practice is recommended by the language developers or by authoritative manuals and has therefore become part of the language's "culture". (Note that Google's SOC is a project rather than a language - the use of camel case is not standardised by the Python language and much Python code makes use of underscores to delimit variable names).
Style guidelines often distinguish between upper and lower camel case, typically specifying which variety should be used for specific kinds of entities: variables, record fields
Field (computer science)
In computer science, data that has several parts can be divided into fields. Relational databases arrange data as sets of database records, also called rows. Each record consists of several fields; the fields of all records form the columns....
, method
Method (computer science)
In object-oriented programming, a method is a subroutine associated with a class. Methods define the behavior to be exhibited by instances of the associated class at program run time...
s, procedures, types, etc. These rules are sometimes supported by static analysis
Static code analysis
Static program analysis is the analysis of computer software that is performed without actually executing programs built from that software In most cases the analysis is performed on some version of the source code and in the other cases some form of the object code...
tools that check source code for adherence.
The original Hungarian notation
Hungarian notation
Hungarian notation is an identifier naming convention in computer programming, in which the name of a variable or function indicates its type or intended use...
for programming, for example, specifies that a lowercase abbreviation for the "usage type" (not data type) should prefix all variable names, with the remainder of the name in upper camel case; as such it is a form of lower camel case.
Programming identifiers often need to contain acronyms and initialisms which are already in upper case, such as "old HTML file". By analogy with the title case rules, the natural camel case rendering would have the abbreviation all in upper case, namely "oldHTMLFile". However, this approach is problematic when two acronyms occur together (e.g., "parse DBM XML" would become "parseDBMXML") or when the standard mandates lower camel case but the name begins with an abbreviation (e.g. "SQL server" would become "sQLServer"). For this reason, some programmers prefer to treat abbreviations as if they were lower case words and write "oldHtmlFile", "parseDbmXml" or "sqlServer".
Wiki link markup
Camel case is used in some wiki markup languagesWikitext
Wikitext language, or wiki markup, is a lightweight markup language used to write pages in wiki websites, such as Wikipedia, and is a simplified alternative/intermediate to HTML. Its ultimate purpose is to be converted by wiki software into HTML, which in turn is served to web browsers.There is no...
for terms that should be automatically linked to other wiki
Wiki
A wiki is a website that allows the creation and editing of any number of interlinked web pages via a web browser using a simplified markup language or a WYSIWYG text editor. Wikis are typically powered by wiki software and are often used collaboratively by multiple users. Examples include...
pages. This convention was originally used in Ward Cunningham
Ward Cunningham
Howard G. "Ward" Cunningham is an American computer programmer who developed the first wiki. A pioneer in both design patterns and Extreme Programming, he started programming the software WikiWikiWeb in 1994 and installed it on the website of his software consultancy, Cunningham & Cunningham , on...
's original wiki software
Wiki software
Wiki software is collaborative software that runs a wiki, i.e., a website that allows users to create and collaboratively edit web pages via a web browser. A wiki system is usually a web application that runs on one or more web servers...
, the WikiWikiWeb
WikiWikiWeb
WikiWikiWeb is a term that has been used to refer to four things: the first wiki, or user-editable website, launched on 25 March 1995 by Ward Cunningham as part of the Portland Pattern Repository ; the Perl-based application that was used to run it, also developed by Cunningham, which was the first...
and is still used by some other wikis, such as FosWiki, JSPWiki
JSPWiki
JSPWiki is wiki software built around the standard J2EE components of Java, servlets and JSP. It was written by Janne Jalkanen and released under the LGPL. It is currently undergoing incubation with Apache and its license has been changed to the Apache License. The Sun Java System Portal Server...
, TiddlyWiki
TiddlyWiki
TiddlyWiki is an open source single page application wiki. A single HTML file contains CSS, JavaScript, and the content. The content is divided into a series of sections, or Tiddlers. A user is encouraged to read a TiddlyWiki by following links rather than sequentially scrolling down the...
, Trac
Trac
Trac is an open source, web-based project management and bug-tracking tool. The program is inspired by CVSTrac, and was originally named svntrac due to its ability to interface with Subversion. It is developed and maintained by Edgewall Software....
and PMWiki
PmWiki
PmWiki is wiki software written by Patrick R. Michaud in the PHP programming language. It is free software, licensed under the terms of the GNU General Public License.-Design focus:...
. Wikipedia
Wikipedia
Wikipedia is a free, web-based, collaborative, multilingual encyclopedia project supported by the non-profit Wikimedia Foundation. Its 20 million articles have been written collaboratively by volunteers around the world. Almost all of its articles can be edited by anyone with access to the site,...
formerly used camel case linking as well, but switched to explicit link markup using square brackets and many other wiki sites have done the same. Some wikis which use a different link markup by default have an option (sometimes with a plugin) to enable camel case links. Some wikis which do not use camel case linking may still use the camel case as a naming convention, such as AboutUs.
Other uses
The NIEMNational Information Exchange Model
The National Information Exchange Model is an XML-based information exchange framework from the United States. NIEM represents a collaborative partnership of agencies and organizations across all levels of government and with private industry...
registry requires that XML
Extensible Markup Language
Extensible Markup Language is a set of rules for encoding documents in machine-readable form. It is defined in the XML 1.0 Specification produced by the W3C, and several other related specifications, all gratis open standards....
data elements use upper camel case and XML attributes use lower camel case.
Most popular command-line interfaces
Shell (computing)
A shell is a piece of software that provides an interface for users of an operating system which provides access to the services of a kernel. However, the term is also applied very loosely to applications and may include any software that is "built around" a particular component, such as web...
and scripting
Shell script
A shell script is a script written for the shell, or command line interpreter, of an operating system. It is often considered a simple domain-specific programming language...
languages cannot easily handle file names that contain embedded spaces (usually requiring the name to be put in quotes). Therefore, users of those systems often resort to camel case (or underscores, hyphens and other "safe" characters) for compound file names like MyJobResume.pdf.
Current usage in natural languages
Camel case has been used in languages other than EnglishEnglish language
English is a West Germanic language that arose in the Anglo-Saxon kingdoms of England and spread into what was to become south-east Scotland under the influence of the Anglian medieval kingdom of Northumbria...
for a variety of purposes, including the ones below:
Orthographic markings
Camel case is sometimes used in the transcription of certain scripts, to differentiate letters or markings. An example is the rendering of TibetanTibetan language
The Tibetan languages are a cluster of mutually-unintelligible Tibeto-Burman languages spoken primarily by Tibetan peoples who live across a wide area of eastern Central Asia bordering the Indian subcontinent, including the Tibetan Plateau and the northern Indian subcontinent in Baltistan, Ladakh,...
proper names like rLobsang: the "r" here stands for a prefix glyph in the original script that functions as tone
Tone (linguistics)
Tone is the use of pitch in language to distinguish lexical or grammatical meaning—that is, to distinguish or inflect words. All verbal languages use pitch to express emotional and other paralinguistic information, and to convey emphasis, contrast, and other such features in what is called...
marker rather than a normal letter. Another example is tsIurku, a Latin transcription of the Chechen
Chechen language
The Chechen language is spoken by more than 1.5 million people, mostly in Chechnya and by Chechen people elsewhere. It is a member of the Northeast Caucasian languages.-Classification:...
term for the capping stone of the characteristic Medieval defensive towers
Vainakh medieval towers
The Nakh medieval towers were a characteristic feature of medieval architecture of the Nakh peoples in Chechenya and Ingushetia, with few parallels outside that region. Some towers were used as dwellings, others had a military purpose; some combined both functions.The roots of Nakh tower...
of Chechenia and Ingushetia
Ingushetia
The Republic of Ingushetia is a federal subject of Russia , located in the North Caucasus region with its capital at Magas. In terms of area, the republic is the smallest of Russia's federal subjects except for the two federal cities, Moscow and Saint Petersburg...
; the capital letter "I" here denoting a phoneme
Phoneme
In a language or dialect, a phoneme is the smallest segmental unit of sound employed to form meaningful contrasts between utterances....
distinct from the one transcribed as "i".
Inflection prefixes
Camel case may also be used when writing proper names in languages that inflect words by attaching prefixes to them. In some of those languages, the custom is to leave the prefix in lower case and capitalize the root.This convention is used in Irish orthography
Irish orthography
Irish orthography has evolved over many centuries, since Old Irish was first written down in the Latin alphabet in about the 6th century AD. Prior to that, Primitive Irish was written in Ogham...
as well as Scots Gaelic orthography
Scottish Gaelic alphabet
The Scottish Gaelic alphabet contains 18 letters, five of which are vowels. The letters are :The five vowels also appear with grave accents, the absence or presence of which can change the meaning of a word drastically as in bàta versus bata :The acute accent is also used on some vowels:Since the...
; e.g., ("in Galway
Galway
Galway or City of Galway is a city in County Galway, Republic of Ireland. It is the sixth largest and the fastest-growing city in Ireland. It is also the third largest city within the Republic and the only city in the Province of Connacht. Located on the west coast of Ireland, it sits on the...
"), from ("Galway"); ("the Scottish person
Scottish people
The Scottish people , or Scots, are a nation and ethnic group native to Scotland. Historically they emerged from an amalgamation of the Picts and Gaels, incorporating neighbouring Britons to the south as well as invading Germanic peoples such as the Anglo-Saxons and the Norse.In modern use,...
"), from ("Scottish person"); ("to Ireland
Ireland
Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...
"), from ("Ireland).
Similarly, in transliteration of the Hebrew language
Hebrew language
Hebrew is a Semitic language of the Afroasiatic language family. Culturally, is it considered by Jews and other religious groups as the language of the Jewish people, though other Jewish languages had originated among diaspora Jews, and the Hebrew language is also used by non-Jewish groups, such...
, haIvrit means "the Hebrew person" and biYerushalayim means "in Jerusalem".
This convention is also used by several Bantu languages
Bantu languages
The Bantu languages constitute a traditional sub-branch of the Niger–Congo languages. There are about 250 Bantu languages by the criterion of mutual intelligibility, though the distinction between language and dialect is often unclear, and Ethnologue counts 535 languages...
(e.g., kiSwahili = "Swahili language
Swahili language
Swahili or Kiswahili is a Bantu language spoken by various ethnic groups that inhabit several large stretches of the Mozambique Channel coastline from northern Kenya to northern Mozambique, including the Comoro Islands. It is also spoken by ethnic minority groups in Somalia...
", isiZulu = "Zulu language
Zulu language
Zulu is the language of the Zulu people with about 10 million speakers, the vast majority of whom live in South Africa. Zulu is the most widely spoken home language in South Africa as well as being understood by over 50% of the population...
") and several indigenous languages of Mexico
Languages of Mexico
The government of Mexico recognizes 68 distinct indigenous Amerindian languages as national languages in addition to Spanish. According to the Commission for the Development of Indigenous Peoples and National Institute of Indigenous Languages [INALI], while 10-14% of the population identifies as...
(e.g. Nahuatl, Totonacan
Totonacan languages
The Totonacan languages are a family of closely related languages spoken by approximately 200,000 Totonac and Tepehua people in the states of Veracruz, Puebla, and Hidalgo in Mexico...
, Mixe–Zoque and some Oto-Manguean
Oto-Manguean languages
Oto-Manguean languages are a large family comprising several families of Native American languages. All of the Oto-Manguean languages that are now spoken are indigenous to Mexico, but the Manguean branch of the family, which is now extinct, was spoken as far south as Nicaragua and Costa Rica.The...
languages).
In abbreviations and acronyms
Abbreviations of some academic qualifications are sometimes presented in camel case without punctuation, e.g. PhDDoctor of Philosophy
Doctor of Philosophy, abbreviated as Ph.D., PhD, D.Phil., or DPhil , in English-speaking countries, is a postgraduate academic degree awarded by universities...
or BSc
Bachelor of Science
A Bachelor of Science is an undergraduate academic degree awarded for completed courses that generally last three to five years .-Australia:In Australia, the BSc is a 3 year degree, offered from 1st year on...
.
In French
French language
French is a Romance language spoken as a first language in France, the Romandy region in Switzerland, Wallonia and Brussels in Belgium, Monaco, the regions of Quebec and Acadia in Canada, and by various communities elsewhere. Second-language speakers of French are distributed throughout many parts...
, camel case acronyms such as OuLiPo
Oulipo
Oulipo is a loose gathering of French-speaking writers and mathematicians which seeks to create works using constrained writing techniques. It was founded in 1960 by Raymond Queneau and François Le Lionnais...
(1960) were favored for a time as alternatives to initialisms.
Camel case is often used to transliterate initialisms into alphabets where two letters may be required to represent a single character of the original alphabet, e.g., DShK
DShK
The DShK 1938 is a Soviet heavy machine gun firing the 12.7x108mm cartridge. The weapon was also used as a heavy infantry machine gun, in which case it was frequently deployed with a two-wheeled mounting and a single-sheet armour-plate shield...
from Cyrillic ДШК.
Honorifics within compound words
In several languages, including English, pronounPronoun
In linguistics and grammar, a pronoun is a pro-form that substitutes for a noun , such as, in English, the words it and he...
s and possessive
Possessive
Possessive may be:* Possessive case* Possessive adjective* Possessive pronoun* Possessive suffix* Possessive construction, pattern among words indicating possession * For possessive behavior in a relationship, see Attachment in adults...
s may be capitalized to indicate respect, e.g., when referring to the reader of a formal letter or to God
God
God is the English name given to a singular being in theistic and deistic religions who is either the sole deity in monotheism, or a single deity in polytheism....
. In some of those languages, the capitalization is customarily retained even when those words occur within compound words or suffixed to a verb. For example, in Italian
Italian language
Italian is a Romance language spoken mainly in Europe: Italy, Switzerland, San Marino, Vatican City, by minorities in Malta, Monaco, Croatia, Slovenia, France, Libya, Eritrea, and Somalia, and by immigrant communities in the Americas and Australia...
one would write ("offering to You respectful salutations") or ("adore Him").
Other uses
In GermanGerman language
German is a West Germanic language, related to and classified alongside English and Dutch. With an estimated 90 – 98 million native speakers, German is one of the world's major languages and is the most widely-spoken first language in the European Union....
, all nouns carry a grammatical gender
Grammatical gender
Grammatical gender is defined linguistically as a system of classes of nouns which trigger specific types of inflections in associated words, such as adjectives, verbs and others. For a system of noun classes to be a gender system, every noun must belong to one of the classes and there should be...
—which, for roles or job titles, is usually masculine. Since the feminist movement
Feminist movement
The feminist movement refers to a series of campaigns for reforms on issues such as reproductive rights, domestic violence, maternity leave, equal pay, women's suffrage, sexual harassment and sexual violence...
of the 1980s, some writers and publishers have been using the feminine title suffixes -in (singular
Grammatical number
In linguistics, grammatical number is a grammatical category of nouns, pronouns, and adjective and verb agreement that expresses count distinctions ....
) and -innen (plural) to emphasize the inclusion of females; but written with a capital 'I', to indicate that males are not excluded. Example: ("co-workers,
In German, the names to statutes are also abbreviated using embedded capitals, e.g. StGB (Strafgesetzbuch) for criminal code and PatG (Patentgesetz) for Patent Act.
See also
- All capsAll capsIn typography, all caps refers to text or a font in which all letters are capital letters. All caps is usually used for emphasis. It is commonly seen in the titles on book covers, in advertisements and in newspaper headlines...
- CapitalizationCapitalizationCapitalization is writing a word with its first letter as a majuscule and the remaining letters in minuscules . This of course only applies to those writing systems which have a case distinction...
- Caps lockCaps lockCaps lock is a key on many computer keyboards. Pressing it sets an input mode in which typed letters are uppercase by default. The keyboard remains in caps lock mode until the key is pressed again...
- Letter caseLetter caseIn orthography and typography, letter case is the distinction between the larger majuscule and smaller minuscule letters...
- Roman cursiveRoman cursiveRoman cursive is a form of handwriting used in ancient Rome and to some extent into the Middle Ages. It is customarily divided into old cursive, and new cursive.- Old Roman cursive :...
- Roman square capitalsRoman square capitalsRoman square capitals, also called capitalis monumentalis, inscriptional capitals, elegant capitals and quadrata, are an ancient Roman form of writing, and the basis for modern capital letters....
- Sentence case
- Shift keyShift keyThe shift key is a modifier key on a keyboard, used to type capital letters and other alternate "upper" characters. There are typically two shift keys, on the left and right sides of the row below the home row...
- Small capsSmall capsIn typography, small capitals are uppercase characters set at the same height and weight as surrounding lowercase letters or text figures...
- StudlyCapsStudlyCapsStudlyCaps is a variation of CamelCase in which the individual letters in a word are capitalized and not capitalized, either at random or in some pattern.-History:...
- UnicaseUnicaseA unicase or unicameral alphabet is one that has no case for its letters. Tamil, Arabic, Old Hungarian, Hebrew, Georgian and Hangul are unicase alphabets, while Latin, Greek, Cyrillic and Armenian have two cases for each letter, e.g., B/b, Β/β, Б/б,...
External links
- Examples and history of CamelCase, also WordsSmashedTogetherLikeSo
- .NET Framework General Reference Capitalization Styles
- What's in a nAME(cq)?, by Bill Walsh, at The Slot
- The Science of Word Recognition, by Kevin Larson, Advanced Reading Technology, Microsoft Corporation
- Evolution of underscores in C++
- OASIS Cover Pages: CamelCase for Naming XML-Related Components
- Convert text to CamelCase, Title Case, Uppercase and lowercase