Syntax guessing, also known as guess-the-verb, guess-the-noun and the syntax quest, is a problem sometimes encountered in text-based video games, such as interactive fiction

Interactive fiction

Interactive fiction, often abbreviated IF, describes software simulating environments in which players use text commands to control characters and influence the environment. Works in this form can be understood as literary narratives and as video games. In common usage, the term refers to text...

 games and MUD

MUD

A MUD , pronounced , is a multiplayer real-time virtual world, with the term usually referring to text-based instances of these. MUDs combine elements of role-playing games, hack and slash, player versus player, interactive fiction, and online chat...

s. For various reasons, the command syntax necessary to carry out an action may be obscure, such as with a button where the player must type POKE BUTTON, while PUSH BUTTON does not work (a "guess-the-verb" problem), an item described as a pillow that can only be obtained by typing GET CUSHION rather than GET PILLOW (a "guess-the-noun" problem), or a situation where the command TURN THE DIAL works but TURN DIAL does not (a generalized syntax guessing problem). If syntax guessing is necessary at a critical step, the game may appear unwinnable, with the player stuck until the right phrasing is guessed or is supplied by a walkthrough

Strategy guide

Strategy guides are instruction books that contain hints or complete solutions to specific video games. The line between strategy guides and walkthroughs is somewhat blurred, with the former often containing or being written around the latter. Strategy guides are often published in print, both in...

. A quest

Quest (gaming)

A quest in role-playing video games — including massively multiplayer online role-playing games and their predecessors, MUDs — is a task that a player-controlled character or group of characters may complete in order to gain a reward...

 that requires syntax guessing to complete is a "syntax quest", especially if it consists of little to no content other than syntax guessing.

People whose native language is not English are particularly affected by syntax guessing. TADS

TADS

Text Adventure Development System is a prototype-based domain-specific programming language and set of standard libraries for creating interactive fiction games.-History:...

 games supply a fair list of verbs commonly used in their documentation; if the game designer uses new actions not covered in this list, and which cannot easily be inferred by the purpose and context of the object, the player will probably encounter this problem.

A similar problem can occur when attempting to accomplish a game goal using a certain combination of actions, locations and objects, which may appear rational and legitimate to the player, and are accepted by the game, only to be incorrectly handled and resulting in a gameplay error or game crash.

Examples

An infamous example of syntax guessing was the ending of Leisure Suit Larry 2, where Larry had to put a bag into a bottle to make an improvised bomb. The parser had no problem with minimal phrases and understood LOOK WOMAN equally well as the proper LOOK AT THE WOMAN (and players would usually type simple phrases for speed and easiness). In the ending, however, simple phrases like PUT BAG IN BOTTLE, the first ideas of many players, failed because the parser interpreted BAG as a verb. The only way the parser understood the phrase was by putting THE before BAG, or by referencing an alias such as AIRSICK BAG. Frustrated players tried other verbs, synonyms and conjunctions like INTO, INSIDE, etc. without knowing that only THE was needed.

Another example is in Infocom

Infocom

Infocom was a software company, based in Cambridge, Massachusetts, that produced numerous works of interactive fiction. They also produced one notable business application, a relational database called Cornerstone....

's Enchanter

Enchanter (computer game)

Enchanter is a 1983 interactive fiction computer game written by Marc Blank and Dave Lebling and published by Infocom. It belongs to the fantasy genre and was the first fantasy game published by Infocom after the Zork trilogy...

, where in order to reach into a hole, a player has to type REACH INTO HOLE, while more common and expected phrases such as LOOK IN HOLE or FEEL INSIDE HOLE do not even recognize that there is a hole in the room. Scott Adams

Scott Adams (game designer)

Scott Adams is the co-founder, with ex-wife Alexis, of Adventure International, an early publisher of games for home computers....

' first adventure, the 1978 title Adventureland, required the player to enter the unintuitive UNLIGHT LAMP in order to prevent a lamp from using up its fuel, and would not recognise the verb EXTINGUISH.

The Atari

Atari

Atari is a corporate and brand name owned by several entities since its inception in 1972. It is currently owned by Atari Interactive, a wholly owned subsidiary of the French publisher Atari, SA . The original Atari, Inc. was founded in 1972 by Nolan Bushnell and Ted Dabney. It was a pioneer in...

 8-bit

8-bit

The first widely adopted 8-bit microprocessor was the Intel 8080, being used in many hobbyist computers of the late 1970s and early 1980s, often running the CP/M operating system. The Zilog Z80 and the Motorola 6800 were also used in similar computers...

 text adventure game Cloak Of Death boasted of understanding "32 verbs" in the cassette sleeve. However, the uncommon verbs KICK, MAKE and EXORCISE are each required to complete the game. Each is valid only in a single place and there was no clue in the cassette or game text that these actions were possible.

This was parodied in the adventure game Peasant's Quest, from Homestarrunner.com, where the player is forced to use the unlikely phrase DEPLOY BABY in order to complete a puzzle.