#
#
# 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