Introduction

The re: module wraps Go's regexp package. See the doc (http://godoc.org/regexp) for the Go package for syntax of regular expressions and replacement patterns.

Functions

Function usages notations follow the same convention as the builtin module doc (/ref/builtin.html).

The following options are supported by multiple functions in this module:

•: &posix (defaults to $false): Use POSIX ERE syntax. See also doc (http://godoc.org/regexp#CompilePOSIX) in Go package.
•: &longest (defaults to $false): Prefer leftmost-longest match. See also doc (http://godoc.org/regexp#Regexp.Longest) in Go package.
•: &max (defaults to -1): If non-negative, maximum number of results.

find

re:find &posix=$false &longest=$false &max=-1 $pattern $source

Find all matches of $pattern in $source.

Each match is represented by a map-like value $m; $m[text], $m[start] and $m[end] are the text, start and end positions (as byte indicies into $source) of the match; $m[groups] is a list of submatches for capture groups in the pattern. A submatch has a similar structure to a match, except that it does not have a group key. The entire pattern is an implicit capture group, and it always appears first.

Examples:

~> re:find . ab
▶ [&text=a &start=0 &end=1 &groups=[[&text=a &start=0 &end=1]]]
▶ [&text=b &start=1 &end=2 &groups=[[&text=b &start=1 &end=2]]]
~> re:find '[A-Z]([0-9])' 'A1 B2'
▶ [&text=A1 &start=0 &end=2 &groups=[[&text=A1 &start=0 &end=2] [&text=1 &start=1 &end=2]]]
▶ [&text=B2 &start=3 &end=5 &groups=[[&text=B2 &start=3 &end=5] [&text=2 &start=4 &end=5]]]

match

re:match &posix=$false $pattern $source

Determine whether $pattern matches $source. The pattern is not anchored. Examples:

~> re:match . xyz
▶ $true
~> re:match . ''
▶ $false
~> re:match '[a-z]' A
▶ $false

replace

re:replace &posix=$false &longest=$false &literal=$false $pattern $repl $source

Replace all occurrences of $pattern in $source with $repl.

The replacement $repl can be either

1.: A string-typed replacement template. The template can use $name or ${name} patterns to refer to capture groups, where name consists of letters, digits and underscores. Numbered patterns like $1 refer to capture groups by their order, while named patterns like $stem refer to capture groups by their names (specified using the syntax (?P<name>...)). Use $$ for a literal dollar sign. The name is taken as long as possible; for instance, $1a is the same as ${1a}.

See also doc of Go's regexp package on the template syntax (https://godoc.org/regexp#Regexp.Expand).

2.: A function that takes a string argument and outputs a string. For each match, the function is called with the content of the match, and its output is used as the replacement.

If $literal is true, $repl must be a string and is treated literally instead of as a pattern.

Example:

~> re:replace '(ba|z)sh' '${1}SH' 'bash and zsh'
▶ 'baSH and zSH'
~> re:replace '(ba|z)sh' elvish 'bash and zsh rock'
▶ 'elvish and elvish rock'
~> re:replace '(ba|z)sh' [x]{ put [&bash=BaSh &zsh=ZsH][$x] } 'bash and zsh'
▶ 'BaSh and ZsH'

split

re:split &posix=$false &longest=$false &max=-1 $pattern $source

Split $source, using $pattern as separators. Examples:

~> re:split : /usr/sbin:/usr/bin:/bin
▶ /usr/sbin
▶ /usr/bin
▶ /bin
~> re:split &max=2 : /usr/sbin:/usr/bin:/bin
▶ /usr/sbin
▶ /usr/bin:/bin

quote

re:quote $string

Quote $string. Examples:

~> re:quote a.txt
▶ a\.txt
~> re:quote '(*)'
▶ '\(\*\)'

February 8, 2019

Elvish 0.12