Fork of yml2 for pypi maintenance
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# YPL parser 1.5
# written by VB.
import re
import sys, codecs
class keyword(str): pass
class code(str): pass
class ignore(object):
def __init__(self, regex_text, *args):
self.regex = re.compile(regex_text, *args)
class _and(object):
def __init__(self, something):
self.obj = something
class _not(_and): pass
class Name(str):
def __init__(self, *args):
self.line = 0
self.file = ""
class Symbol(list):
def __init__(self, name, what):
self.__name__ = name
self.append(name)
self.what = what
self.append(what)
def __call__(self):
return self.what
def __str__(self):
return 'Symbol(' + repr(self.__name__) + ', ' + repr(self.what) + ')'
def __repr__(self):
return str(self)
word_regex = re.compile(r"\w+")
rest_regex = re.compile(r".*")
print_trace = False
def skip(skipper, text, skipWS, skipComments):
if skipWS:
t = text.lstrip()
else:
t = text
if skipComments:
try:
while True:
skip, t = skipper.parseLine(t, skipComments, [], skipWS, None)
if skipWS:
t = t.lstrip()
except: pass
return t
class parser(object):
def __init__(self, another = False, p = False):
self.restlen = -1
if not(another):
self.skipper = parser(True, p)
self.skipper.packrat = p
else:
self.skipper = self
self.lines = None
self.textlen = 0
self.memory = {}
self.packrat = p
# parseLine():
# textline: text to parse
# pattern: pyPEG language description
# resultSoFar: parsing result so far (default: blank list [])
# skipWS: Flag if whitespace should be skipped (default: True)
# skipComments: Python functions returning pyPEG for matching comments
#
# returns: pyAST, textrest
#
# raises: SyntaxError(reason) if textline is detected not being in language
# described by pattern
#
# SyntaxError(reason) if pattern is an illegal language description
def parseLine(self, textline, pattern, resultSoFar = [], skipWS = True, skipComments = None):
name = None
_textline = textline
_pattern = pattern
def R(result, text):
if __debug__:
if print_trace:
try:
if _pattern.__name__ != "comment":
sys.stderr.write("match: " + _pattern.__name__ + "\n")
except: pass
if self.restlen == -1:
self.restlen = len(text)
else:
self.restlen = min(self.restlen, len(text))
res = resultSoFar
if name and result:
name.line = self.lineNo()
res.append(Symbol(name, result))
elif name:
name.line = self.lineNo()
res.append(Symbol(name, []))
elif result:
if type(result) is type([]):
res.extend(result)
else:
res.extend([result])
if self.packrat:
self.memory[(len(_textline), id(_pattern))] = (res, text)
return res, text
def syntaxError():
if self.packrat:
self.memory[(len(_textline), id(_pattern))] = False
raise SyntaxError()
if self.packrat:
try:
result = self.memory[(len(textline), id(pattern))]
if result:
return result
else:
raise SyntaxError()
except: pass
if callable(pattern):
if __debug__:
if print_trace:
try:
if pattern.__name__ != "comment":
sys.stderr.write("testing with " + pattern.__name__ + ": " + textline[:40] + "\n")
except: pass
if pattern.__name__[0] != "_":
name = Name(pattern.__name__)
pattern = pattern()
if callable(pattern):
pattern = (pattern,)
text = skip(self.skipper, textline, skipWS, skipComments)
pattern_type = type(pattern)
if pattern_type is str:
if text[:len(pattern)] == pattern:
text = skip(self.skipper, text[len(pattern):], skipWS, skipComments)
return R(None, text)
else:
syntaxError()
elif pattern_type is keyword:
m = word_regex.match(text)
if m:
if m.group(0) == pattern:
text = skip(self.skipper, text[len(pattern):], skipWS, skipComments)
return R(None, text)
else:
syntaxError()
else:
syntaxError()
elif pattern_type is _not:
try:
r, t = self.parseLine(text, pattern.obj, [], skipWS, skipComments)
except:
return resultSoFar, textline
syntaxError()
elif pattern_type is _and:
r, t = self.parseLine(text, pattern.obj, [], skipWS, skipComments)
return resultSoFar, textline
elif pattern_type is type(word_regex) or pattern_type is ignore:
if pattern_type is ignore:
pattern = pattern.regex
m = pattern.match(text)
if m:
text = skip(self.skipper, text[len(m.group(0)):], skipWS, skipComments)
if pattern_type is ignore:
return R(None, text)
else:
return R(m.group(0), text)
else:
syntaxError()
elif pattern_type is tuple:
result = []
n = 1
for p in pattern:
if type(p) is type(0):
n = p
else:
if n>0:
for i in range(n):
result, text = self.parseLine(text, p, result, skipWS, skipComments)
elif n==0:
if text == "":
pass
else:
try:
newResult, newText = self.parseLine(text, p, result, skipWS, skipComments)
result, text = newResult, newText
except SyntaxError:
pass
elif n<0:
found = False
while True:
try:
newResult, newText = self.parseLine(text, p, result, skipWS, skipComments)
result, text, found = newResult, newText, True
except SyntaxError:
break
if n == -2 and not(found):
syntaxError()
n = 1
return R(result, text)
elif pattern_type is list:
result = []
found = False
for p in pattern:
try:
result, text = self.parseLine(text, p, result, skipWS, skipComments)
found = True
except SyntaxError:
pass
if found:
break
if found:
return R(result, text)
else:
syntaxError()
else:
raise SyntaxError("illegal type in grammar: " + pattern_type)
def lineNo(self):
if not(self.lines): return ""
if self.restlen == -1: return ""
parsed = self.textlen - self.restlen
left, right = 0, len(self.lines)
while True:
mid = int((right + left) / 2)
if self.lines[mid][0] <= parsed:
try:
if self.lines[mid + 1][0] >= parsed:
try:
return self.lines[mid + 1][1] + ":" + self.lines[mid + 1][2]
except:
return ""
else:
left = mid + 1
except:
try:
return self.lines[mid + 1][1] + ":" + self.lines[mid + 1][2]
except:
return ""
else:
right = mid - 1
if left > right:
return ""
# plain module API
def parseLine(textline, pattern, resultSoFar = [], skipWS = True, skipComments = None, packrat = False):
p = parser(p=packrat)
text = skip(p.skipper, textline, skipWS, skipComments)
ast, text = p.parseLine(text, pattern, resultSoFar, skipWS, skipComments)
return ast, text
# parse():
# language: pyPEG language description
# lineSource: a fileinput.FileInput object
# skipWS: Flag if whitespace should be skipped (default: True)
# skipComments: Python function which returns pyPEG for matching comments
# packrat: use memoization
# lineCount: add line number information to AST
#
# returns: pyAST
#
# raises: SyntaxError(reason), if a parsed line is not in language
# SyntaxError(reason), if the language description is illegal
def parse(language, lineSource, skipWS = True, skipComments = None, packrat = False, lineCount = True):
lines, lineNo = [], 0
while callable(language):
language = language()
orig, ld = "", 0
for line in lineSource:
if lineSource.isfirstline():
ld = 1
else:
ld += 1
lines.append((len(orig), lineSource.filename(), lineSource.lineno() - 1))
orig += line
textlen = len(orig)
try:
p = parser(p=packrat)
p.textlen = len(orig)
if lineCount:
p.lines = lines
else:
p.line = None
text = skip(p.skipper, orig, skipWS, skipComments)
result, text = p.parseLine(text, language, [], skipWS, skipComments)
if text:
raise SyntaxError()
except SyntaxError as msg:
parsed = textlen - p.restlen
textlen = 0
nn, lineNo, file = 0, 0, ""
for n, ld, l in lines:
if n >= parsed:
break
else:
lineNo = l
nn += 1
file = ld
lineNo += 1
nn -= 1
lineCont = orig.splitlines()[nn]
raise SyntaxError("syntax error in " + file + ":" + lineNo + ": " + lineCont)
return result