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Diffstat (limited to 'nimlib/pure/regexprs.nim')
| -rwxr-xr-x | nimlib/pure/regexprs.nim | 177 |
1 files changed, 177 insertions, 0 deletions
diff --git a/nimlib/pure/regexprs.nim b/nimlib/pure/regexprs.nim new file mode 100755 index 000000000..cff3152cf --- /dev/null +++ b/nimlib/pure/regexprs.nim @@ -0,0 +1,177 @@ +# +# +# Nimrod's Runtime Library +# (c) Copyright 2009 Andreas Rumpf +# +# See the file "copying.txt", included in this +# distribution, for details about the copyright. +# + +## Regular expression support for Nimrod. +## Currently this module is implemented by providing a wrapper around the +## `PRCE (Perl-Compatible Regular Expressions) <http://www.pcre.org>`_ +## C library. This means that your application will depend on the PRCE +## library's licence when using this module, which should not be a problem +## though. +## PRCE's licence follows: +## +## .. include:: ../doc/regexprs.txt +## + +# This is not just a convenient wrapper for the pcre library; the +# API will stay the same if the implementation should change. + +import + pcre, strutils + +type + EInvalidRegEx* = object of EInvalidValue + ## is raised if the pattern is no valid regular expression. + +const + MaxSubpatterns* = 10 + ## defines the maximum number of subpatterns that can be captured. + ## More subpatterns cannot be captured! + +proc match*(s, pattern: string, matches: var openarray[string], + start: int = 0): bool + ## returns ``true`` if ``s[start..]`` matches the ``pattern`` and + ## the captured substrings in the array ``matches``. If it does not + ## match, nothing is written into ``matches`` and ``false`` is + ## returned. + +proc match*(s, pattern: string, start: int = 0): bool + ## returns ``true`` if ``s`` matches the ``pattern`` beginning from ``start``. + +proc matchLen*(s, pattern: string, matches: var openarray[string], + start: int = 0): int + ## the same as ``match``, but it returns the length of the match, + ## if there is no match, -1 is returned. Note that a match length + ## of zero can happen. + +proc find*(s, pattern: string, matches: var openarray[string], + start: int = 0): bool + ## returns ``true`` if ``pattern`` occurs in ``s`` and the captured + ## substrings in the array ``matches``. If it does not match, nothing + ## is written into ``matches``. + +proc find*(s, pattern: string, start: int = 0): bool + ## returns ``true`` if ``pattern`` occurs in ``s``. + +proc rawCompile(pattern: string, flags: cint): PPcre = + var + msg: CString + offset: int + com = pcreCompile(pattern, flags, addr(msg), addr(offset), nil) + if com == nil: + var e: ref EInvalidRegEx + new(e) + e.msg = $msg & "\n" & pattern & "\n" & repeatChar(offset) & "^\n" + raise e + return com + +proc matchOrFind(s: string, pattern: PPcre, matches: var openarray[string], + start: cint): cint = + var + rawMatches: array [0..maxSubpatterns * 3 - 1, cint] + res = int(pcreExec(pattern, nil, s, len(s), start, 0, + cast[ptr cint](addr(rawMatches)), maxSubpatterns * 3)) + dealloc(pattern) + if res < 0: return res + for i in 0..res-1: + var + a = rawMatches[i * 2] + b = rawMatches[i * 2 + 1] + if a >= 0'i32: matches[i] = copy(s, a, int(b)-1) + else: matches[i] = "" + return res + +proc matchOrFind(s: string, pattern: PPcre, start: cint): cint = + var + rawMatches: array [0..maxSubpatterns * 3 - 1, cint] + res = pcreExec(pattern, nil, s, len(s), start, 0, + cast[ptr cint](addr(rawMatches)), maxSubpatterns * 3) + dealloc(pattern) + return res + +proc match(s, pattern: string, matches: var openarray[string], + start: int = 0): bool = + return matchOrFind(s, rawCompile(pattern, PCRE_ANCHORED), + matches, start) >= 0'i32 + +proc matchLen(s, pattern: string, matches: var openarray[string], + start: int = 0): int = + return matchOrFind(s, rawCompile(pattern, PCRE_ANCHORED), matches, start) + +proc find(s, pattern: string, matches: var openarray[string], + start: int = 0): bool = + return matchOrFind(s, rawCompile(pattern, PCRE_MULTILINE), + matches, start) >= 0'i32 + +proc match(s, pattern: string, start: int = 0): bool = + return matchOrFind(s, rawCompile(pattern, PCRE_ANCHORED), start) >= 0'i32 + +proc find(s, pattern: string, start: int = 0): bool = + return matchOrFind(s, rawCompile(pattern, PCRE_MULTILINE), start) >= 0'i32 + +template `=~` *(s, pattern: expr): expr = + ## This calls ``match`` with an implicit declared ``matches`` array that + ## can be used in the scope of the ``=~`` call: + ## + ## .. code-block:: nimrod + ## + ## if line =~ r"\s*(\w+)\s*\=\s*(\w+)": + ## # matches a key=value pair: + ## echo("Key: ", matches[1]) + ## echo("Value: ", matches[2]) + ## elif line =~ r"\s*(\#.*)": + ## # matches a comment + ## # note that the implicit ``matches`` array is different from the + ## # ``matches`` array of the first branch + ## echo("comment: ", matches[1]) + ## else: + ## echo("syntax error") + ## + when not definedInScope(matches): + var matches: array[0..maxSubPatterns-1, string] + match(s, pattern, matches) + + +const ## common regular expressions + reIdentifier* = r"\b[a-zA-Z_][a-zA-Z_0-9]*\b" ## describes an identifier + reNatural* = r"\b\d+\b" ## describes a natural number + reInteger* = r"\b[-+]?\d+\b" ## describes an integer + reHex* = r"\b0[xX][0-9a-fA-F]+\b" ## describes a hexadecimal number + reBinary* = r"\b0[bB][01]+\b" ## describes a binary number (example: 0b11101) + reOctal* = r"\b0[oO][0-7]+\b" ## describes an octal number (example: 0o777) + reFloat* = r"\b[-+]?[0-9]*\.?[0-9]+([eE][-+]?[0-9]+)?\b" + ## describes a floating point number + reEmail* = r"\b[a-zA-Z0-9!#$%&'*+/=?^_`{|}~\-]+(?:\.[a-zA-Z0-9!#$%&'*+/=?^_`{|}~-]+)" & + r"*@(?:[a-zA-Z0-9](?:[a-zA-Z0-9-]*[a-zA-Z0-9])?\.)+(?:[a-zA-Z]{2}|com|org|" & + r"net|gov|mil|biz|info|mobi|name|aero|jobs|museum)\b" + ## describes a common email address + reURL* = r"\b(http(s)?|ftp|gopher|telnet|file|notes|ms\-help):" & + r"((//)|(\\\\))+[\w\d:#@%/;$()~_?\+\-\=\\\.\&]*\b" + ## describes an URL + +proc verbose*(pattern: string): string {.noSideEffect.} = + ## deletes whitespace from a pattern that is not escaped or in a character + ## class. This is modelled after Perl's ``/x`` modifier. + result = "" + var i = 0 + while i < pattern.len: + case pattern[i] + of ' ', '\t': + inc i + of '\\': + add result, '\\' + add result, pattern[i+1] + inc i, 2 + of '[': + while pattern[i] != ']' and pattern[i] != '\0': + add result, pattern[i] + inc i + else: + add result, pattern[i] + inc i + |