BPEG

BPEG is a parsing expression grammar tool for the command line. It's written in pure C with no dependencies.

Usage

bp [flags] <pattern> [<input files>...]

Flags

• -h --help print the usage and quit
• -v --verbose print verbose debugging info
• -i --ignore-case perform a case-insensitive match
• -I --inplace perform replacements or filtering in-place on files
• -e --explain print an explanation of the matches
• -j --json print matches as JSON objects
• -l --list-files print only filenames containing matches
• -d --define <name>:<def> define a grammar rule
• -D --define-string <name>:<def> define a grammar rule (string-pattern)
• -p --pattern <pat> provide a pattern (equivalent to bp '\(<pat>)')
• -P --pattern-string <pat> provide a string pattern (equivalent to bp '<pat>', but may be useful if '<pat>' begins with a '-')
• -r --replace <replacement> replace the input pattern with the given replacement
• -m --mode <mode> set the behavior mode (defult: find-all)
• -g --grammar <grammar file> use the specified file as a grammar

See man ./bp.1 for more details.

BPEG Patterns

BPEG patterns are a mixture of Parsing Expression Grammar and Regular Expression syntax, with a preference for prefix operators instead of suffix operators.

Pattern	Meaning
pat1 pat2	pat1 followed by pat2
pat1 / pat2	pat1 if it matches, otherwise pat2
...pat	Any text up to and including pat (including newlines)
..pat	Any text up to and including pat (except newlines)
.	Any single character (except newline)
$.	Any single character (including newline)
^^	The start of the input
^	The start of a line
$$	The end of the input
$	The end of a line
__	Zero or more whitespace characters (including newlines)
_	Zero or more whitespace characters (excluding newlines)
`c	The literal character c
`a-z	The character range a through z
`a,b	The character a or the character b
\n, \033, \x0A, etc.	An escape sequence character
\x00-xFF	An escape sequence range (byte 0x00 through 0xFF here)
!pat	pat does not match at the current position
[pat] or pat?	Zero or one occurrences of pat (optional pattern)
5 pat	Exactly 5 occurrences of pat
2-4 pat	Between 2 and 4 occurrences of pat (inclusive)
5+ pat	5 or more occurrences of pat
5+ pat % sep	5 or more occurrences of pat, separated by sep (e.g. 0+ int % "," matches 1,2,3)
*pat	0 or more occurrences of pat (shorthand for 0+pat)
+pat	1 or more occurrences of pat (shorthand for 1+pat)
<pat	pat matches just before the current position (backref)
>pat	pat matches just in front of the current position (lookahead)
@pat	Capture pat (used for text replacement and backreferences)
@foo=pat	Let foo be the text of pat (used for text replacement and backreferences)
{pat => "replacement"}	Match pat and replace it with replacement
{pat @other => "@1"}	Match pat followed by other and replace it with the text of other
{pat @keep=other => "@keep"}	Match pat followed by other and replace it with the text of other
pat1==pat2	pat1, assuming pat2 also matches with the same length
pat1!=pat2	pat1, unless pat2 also matches with the same length
#( block comment )#	A block comment
# line comment	A line comment

See man ./bp.1 for more details.

License

BPEG is provided under the MIT license with the Commons Clause (you can't sell this software without the developer's permission, but you're otherwise free to use, modify, and redistribute it free of charge). See LICENSE for details.