complgen-syntax

Syntax highlight for compleat/complgen, a unified completion generation language for multiple shells such as bash, zsh, fish and powershell.

Syntax

We prioritize syntax highlighting complgen grammars, due to its active development and extended features over compleat. We describe the implemented syntax rules derived from [email protected] from README, with [CG] denoting features specific to complgen:

A usage file *.usage contains commands and definitions, separated by semicolons.

A command consists of a command name followed by a pattern. The command name can be any atom. If there is more than one command in the file, we will attempt to match each of them against the input line.

An atom consists of letters, numbers, and any of the characters _-, starting with a letter or underscore.

• Any atom matches itself: foo matches the string foo.
• a b matches a followed by b.
• a b | c matches either a b or c.
• [a] matches zero or one occurrences of a.
• a... matches one or more occurrences of a
• [a]... matches zero or more occurrences of a.
• [CG] (a | b || c) shows a and b as candidates, and c only when current input matches neither a nor b. || behaves exactly like | when matching, it differs only when offering completions.

Use parentheses to group patterns:

• a (b | c) matches a followed by either b or c.
• (a | b) ... matches a or b followed by any number of additional a or b.

Variables and Constants:

• A variable can be defined with <FOO> = bar and referenced as <FOO>.
• [CG] A special variable <_> matches any shell word.
• [CG] Predefined variables (default constants, though overridable): <PATH> and <DIRECTORY> match file and directory paths, respectively.
• <USER@bash> and <USER@fish> define the <USER> variable, but are shell-specific.

Attribution

Syntax based on complgen grammar by Adam Szkoda.

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