0xshamil / lua-re2

RE2's C and Lua interface

C and Lua wrappers for RE2

C and Lua wrapper for RE2 regular expression library. The Lua wrapper is built on top of C wrapper.

Lua Functions

The Lua wrapper (lua-re2.lua) exposes following functions:

new

syntax: instance = new()

Create an instance which pre-allocate some data structures for captures, to obviate the need of allocating them each time match is called.

The default value of the parameter max-capture is 40.

compile

syntax: pattern, capture_num, err_msg = compile(pattern, [options, max_mem])

Pre-compile the pattern string. Additional options for the regex engine can be passed by the options and max_mem; they are corresponding to RE2's re2::RE2::Options except that the options is using single character, instead of bitmask, to pass the boolean options. The respondance between options and RE2's re2::RE2::Options are following:

option char	re2::RE2::Options	meaning	default value
u	utf8	text and pattern are UTF-8; otherwise Latin-1	true
a	longest_match	search for longest match, not first match	false
e	log_errors	log syntax and execution errors to ERROR	true
l	literal	interpret string as literal, not regexp	false
n	never_nl	never match \n, even if it is in regexp	false
s	dot_nl	dot matches everything including new line	false
c	never_capture	parse all parens as non-capturing	false
i	case_sensitive	match is case-sensitive (regexp can override with (?i) unless in posix_syntax mode)	true
m	multi-line-mode	^ match after any newline, and $ match any before newline	false

match

syntax: captures, errmsg = match(instance, pattern, text, cap_idx)

Match the given pre-compiled pattern against the text. It returns three variables:

| captures | the specified capture(s), see bellow | | errmsg | error message if something wrong took place |

The input parameter cap_idx can take one of the following values: | -1 | return all captures in an array, i-th (i>=0) element contains i-th capture, and 0-th element is the sub-string which tighly matches the entire pattern| | 1 .. the-number-of-capture | return particular capture |

find

syntax: match_or_not = find(pattern, text) return non-nil if match, nil otherwise

match_r

syntax: captures = match_r(instance, pattern, text)

Match the given pre-compiled pattern repeatedly through the full text. It returns all captures in an array if match, nil otherwise.

C Funtions

The interface functions are self-descriptive. Please check the re2c_c.h for details.