mirror of
https://github.com/python/cpython
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312 lines
13 KiB
Python
312 lines
13 KiB
Python
"""Provide advanced parsing abilities for ParenMatch and other extensions.
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HyperParser uses PyParser. PyParser mostly gives information on the
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proper indentation of code. HyperParser gives additional information on
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the structure of code.
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"""
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from keyword import iskeyword
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import string
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from idlelib import pyparse
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# all ASCII chars that may be in an identifier
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_ASCII_ID_CHARS = frozenset(string.ascii_letters + string.digits + "_")
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# all ASCII chars that may be the first char of an identifier
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_ASCII_ID_FIRST_CHARS = frozenset(string.ascii_letters + "_")
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# lookup table for whether 7-bit ASCII chars are valid in a Python identifier
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_IS_ASCII_ID_CHAR = [(chr(x) in _ASCII_ID_CHARS) for x in range(128)]
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# lookup table for whether 7-bit ASCII chars are valid as the first
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# char in a Python identifier
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_IS_ASCII_ID_FIRST_CHAR = \
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[(chr(x) in _ASCII_ID_FIRST_CHARS) for x in range(128)]
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class HyperParser:
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def __init__(self, editwin, index):
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"To initialize, analyze the surroundings of the given index."
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self.editwin = editwin
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self.text = text = editwin.text
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parser = pyparse.Parser(editwin.indentwidth, editwin.tabwidth)
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def index2line(index):
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return int(float(index))
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lno = index2line(text.index(index))
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if not editwin.prompt_last_line:
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for context in editwin.num_context_lines:
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startat = max(lno - context, 1)
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startatindex = repr(startat) + ".0"
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stopatindex = "%d.end" % lno
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# We add the newline because PyParse requires a newline
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# at end. We add a space so that index won't be at end
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# of line, so that its status will be the same as the
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# char before it, if should.
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parser.set_code(text.get(startatindex, stopatindex)+' \n')
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bod = parser.find_good_parse_start(
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editwin._build_char_in_string_func(startatindex))
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if bod is not None or startat == 1:
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break
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parser.set_lo(bod or 0)
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else:
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r = text.tag_prevrange("console", index)
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if r:
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startatindex = r[1]
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else:
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startatindex = "1.0"
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stopatindex = "%d.end" % lno
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# We add the newline because PyParse requires it. We add a
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# space so that index won't be at end of line, so that its
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# status will be the same as the char before it, if should.
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parser.set_code(text.get(startatindex, stopatindex)+' \n')
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parser.set_lo(0)
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# We want what the parser has, minus the last newline and space.
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self.rawtext = parser.code[:-2]
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# Parser.code apparently preserves the statement we are in, so
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# that stopatindex can be used to synchronize the string with
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# the text box indices.
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self.stopatindex = stopatindex
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self.bracketing = parser.get_last_stmt_bracketing()
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# find which pairs of bracketing are openers. These always
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# correspond to a character of rawtext.
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self.isopener = [i>0 and self.bracketing[i][1] >
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self.bracketing[i-1][1]
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for i in range(len(self.bracketing))]
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self.set_index(index)
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def set_index(self, index):
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"""Set the index to which the functions relate.
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The index must be in the same statement.
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"""
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indexinrawtext = (len(self.rawtext) -
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len(self.text.get(index, self.stopatindex)))
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if indexinrawtext < 0:
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raise ValueError("Index %s precedes the analyzed statement"
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% index)
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self.indexinrawtext = indexinrawtext
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# find the rightmost bracket to which index belongs
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self.indexbracket = 0
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while (self.indexbracket < len(self.bracketing)-1 and
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self.bracketing[self.indexbracket+1][0] < self.indexinrawtext):
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self.indexbracket += 1
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if (self.indexbracket < len(self.bracketing)-1 and
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self.bracketing[self.indexbracket+1][0] == self.indexinrawtext and
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not self.isopener[self.indexbracket+1]):
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self.indexbracket += 1
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def is_in_string(self):
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"""Is the index given to the HyperParser in a string?"""
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# The bracket to which we belong should be an opener.
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# If it's an opener, it has to have a character.
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return (self.isopener[self.indexbracket] and
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self.rawtext[self.bracketing[self.indexbracket][0]]
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in ('"', "'"))
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def is_in_code(self):
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"""Is the index given to the HyperParser in normal code?"""
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return (not self.isopener[self.indexbracket] or
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self.rawtext[self.bracketing[self.indexbracket][0]]
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not in ('#', '"', "'"))
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def get_surrounding_brackets(self, openers='([{', mustclose=False):
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"""Return bracket indexes or None.
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If the index given to the HyperParser is surrounded by a
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bracket defined in openers (or at least has one before it),
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return the indices of the opening bracket and the closing
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bracket (or the end of line, whichever comes first).
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If it is not surrounded by brackets, or the end of line comes
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before the closing bracket and mustclose is True, returns None.
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"""
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bracketinglevel = self.bracketing[self.indexbracket][1]
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before = self.indexbracket
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while (not self.isopener[before] or
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self.rawtext[self.bracketing[before][0]] not in openers or
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self.bracketing[before][1] > bracketinglevel):
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before -= 1
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if before < 0:
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return None
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bracketinglevel = min(bracketinglevel, self.bracketing[before][1])
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after = self.indexbracket + 1
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while (after < len(self.bracketing) and
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self.bracketing[after][1] >= bracketinglevel):
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after += 1
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beforeindex = self.text.index("%s-%dc" %
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(self.stopatindex, len(self.rawtext)-self.bracketing[before][0]))
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if (after >= len(self.bracketing) or
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self.bracketing[after][0] > len(self.rawtext)):
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if mustclose:
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return None
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afterindex = self.stopatindex
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else:
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# We are after a real char, so it is a ')' and we give the
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# index before it.
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afterindex = self.text.index(
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"%s-%dc" % (self.stopatindex,
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len(self.rawtext)-(self.bracketing[after][0]-1)))
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return beforeindex, afterindex
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# the set of built-in identifiers which are also keywords,
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# i.e. keyword.iskeyword() returns True for them
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_ID_KEYWORDS = frozenset({"True", "False", "None"})
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@classmethod
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def _eat_identifier(cls, str, limit, pos):
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"""Given a string and pos, return the number of chars in the
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identifier which ends at pos, or 0 if there is no such one.
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This ignores non-identifier eywords are not identifiers.
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"""
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is_ascii_id_char = _IS_ASCII_ID_CHAR
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# Start at the end (pos) and work backwards.
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i = pos
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# Go backwards as long as the characters are valid ASCII
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# identifier characters. This is an optimization, since it
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# is faster in the common case where most of the characters
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# are ASCII.
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while i > limit and (
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ord(str[i - 1]) < 128 and
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is_ascii_id_char[ord(str[i - 1])]
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):
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i -= 1
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# If the above loop ended due to reaching a non-ASCII
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# character, continue going backwards using the most generic
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# test for whether a string contains only valid identifier
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# characters.
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if i > limit and ord(str[i - 1]) >= 128:
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while i - 4 >= limit and ('a' + str[i - 4:pos]).isidentifier():
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i -= 4
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if i - 2 >= limit and ('a' + str[i - 2:pos]).isidentifier():
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i -= 2
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if i - 1 >= limit and ('a' + str[i - 1:pos]).isidentifier():
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i -= 1
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# The identifier candidate starts here. If it isn't a valid
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# identifier, don't eat anything. At this point that is only
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# possible if the first character isn't a valid first
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# character for an identifier.
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if not str[i:pos].isidentifier():
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return 0
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elif i < pos:
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# All characters in str[i:pos] are valid ASCII identifier
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# characters, so it is enough to check that the first is
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# valid as the first character of an identifier.
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if not _IS_ASCII_ID_FIRST_CHAR[ord(str[i])]:
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return 0
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# All keywords are valid identifiers, but should not be
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# considered identifiers here, except for True, False and None.
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if i < pos and (
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iskeyword(str[i:pos]) and
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str[i:pos] not in cls._ID_KEYWORDS
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):
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return 0
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return pos - i
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# This string includes all chars that may be in a white space
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_whitespace_chars = " \t\n\\"
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def get_expression(self):
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"""Return a string with the Python expression which ends at the
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given index, which is empty if there is no real one.
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"""
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if not self.is_in_code():
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raise ValueError("get_expression should only be called "
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"if index is inside a code.")
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rawtext = self.rawtext
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bracketing = self.bracketing
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brck_index = self.indexbracket
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brck_limit = bracketing[brck_index][0]
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pos = self.indexinrawtext
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last_identifier_pos = pos
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postdot_phase = True
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while 1:
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# Eat whitespaces, comments, and if postdot_phase is False - a dot
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while 1:
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if pos>brck_limit and rawtext[pos-1] in self._whitespace_chars:
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# Eat a whitespace
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pos -= 1
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elif (not postdot_phase and
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pos > brck_limit and rawtext[pos-1] == '.'):
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# Eat a dot
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pos -= 1
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postdot_phase = True
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# The next line will fail if we are *inside* a comment,
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# but we shouldn't be.
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elif (pos == brck_limit and brck_index > 0 and
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rawtext[bracketing[brck_index-1][0]] == '#'):
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# Eat a comment
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brck_index -= 2
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brck_limit = bracketing[brck_index][0]
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pos = bracketing[brck_index+1][0]
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else:
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# If we didn't eat anything, quit.
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break
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if not postdot_phase:
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# We didn't find a dot, so the expression end at the
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# last identifier pos.
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break
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ret = self._eat_identifier(rawtext, brck_limit, pos)
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if ret:
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# There is an identifier to eat
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pos = pos - ret
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last_identifier_pos = pos
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# Now, to continue the search, we must find a dot.
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postdot_phase = False
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# (the loop continues now)
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elif pos == brck_limit:
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# We are at a bracketing limit. If it is a closing
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# bracket, eat the bracket, otherwise, stop the search.
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level = bracketing[brck_index][1]
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while brck_index > 0 and bracketing[brck_index-1][1] > level:
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brck_index -= 1
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if bracketing[brck_index][0] == brck_limit:
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# We were not at the end of a closing bracket
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break
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pos = bracketing[brck_index][0]
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brck_index -= 1
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brck_limit = bracketing[brck_index][0]
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last_identifier_pos = pos
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if rawtext[pos] in "([":
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# [] and () may be used after an identifier, so we
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# continue. postdot_phase is True, so we don't allow a dot.
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pass
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else:
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# We can't continue after other types of brackets
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if rawtext[pos] in "'\"":
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# Scan a string prefix
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while pos > 0 and rawtext[pos - 1] in "rRbBuU":
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pos -= 1
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last_identifier_pos = pos
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break
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else:
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# We've found an operator or something.
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break
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return rawtext[last_identifier_pos:self.indexinrawtext]
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if __name__ == '__main__':
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from unittest import main
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main('idlelib.idle_test.test_hyperparser', verbosity=2)
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