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bpo-32874: IDLE: add tests for pyparse (GH-5755)

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There are no code changes other than comments and docstrings.
This commit is contained in:
Cheryl Sabella 2018-02-21 22:48:36 -05:00 • committed by Terry Jan Reedy
parent ba518804bf
commit c84cf6c03f
3 changed files with 619 additions and 66 deletions
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161
Lib/idlelib/pyparse.py
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@ -1,8 +1,20 @@
"""Define partial Python code Parser used by editor and hyperparser.
Instances of StringTranslatePseudoMapping are used with str.translate.
The following bound search and match functions are defined:
_synchre - start of popular statement;
_junkre - whitespace or comment line;
_match_stringre: string, possibly without closer;
_itemre - line that may have bracket structure start;
_closere - line that must be followed by dedent.
_chew_ordinaryre - non-special characters.
"""
from collections.abc import Mapping
import re
import sys
# Reason last stmt is continued (or C_NONE if it's not).
# Reason last statement is continued (or C_NONE if it's not).
(C_NONE, C_BACKSLASH, C_STRING_FIRST_LINE,
C_STRING_NEXT_LINES, C_BRACKET) = range(5)
@ -10,7 +22,7 @@ if 0: # for throwaway debugging output
def dump(*stuff):
sys.__stdout__.write(" ".join(map(str, stuff)) + "\n")
# Find what looks like the start of a popular stmt.
# Find what looks like the start of a popular statement.
_synchre = re.compile(r"""
^
@ -70,7 +82,7 @@ _itemre = re.compile(r"""
[^\s#\\] # if we match, m.end()-1 is the interesting char
""", re.VERBOSE).match
# Match start of stmts that should be followed by a dedent.
# Match start of statements that should be followed by a dedent.
_closere = re.compile(r"""
\s*
@ -146,19 +158,20 @@ class Parser:
self.str = s
self.study_level = 0
# Return index of a good place to begin parsing, as close to the
# end of the string as possible. This will be the start of some
# popular stmt like "if" or "def". Return None if none found:
# the caller should pass more prior context then, if possible, or
# if not (the entire program text up until the point of interest
# has already been tried) pass 0 to set_lo.
#
# This will be reliable iff given a reliable is_char_in_string
# function, meaning that when it says "no", it's absolutely
# guaranteed that the char is not in a string.
def find_good_parse_start(self, is_char_in_string=None,
_synchre=_synchre):
"""
Return index of a good place to begin parsing, as close to the
end of the string as possible. This will be the start of some
popular stmt like "if" or "def". Return None if none found:
the caller should pass more prior context then, if possible, or
if not (the entire program text up until the point of interest
has already been tried) pass 0 to set_lo().
This will be reliable iff given a reliable is_char_in_string()
function, meaning that when it says "no", it's absolutely
guaranteed that the char is not in a string.
"""
str, pos = self.str, None
if not is_char_in_string:
@ -173,7 +186,7 @@ class Parser:
i = str.rfind(":\n", 0, limit)
if i < 0:
break
i = str.rfind('\n', 0, i) + 1 # start of colon line
i = str.rfind('\n', 0, i) + 1 # start of colon line (-1+1=0)
m = _synchre(str, i, limit)
if m and not is_char_in_string(m.start()):
pos = m.start()
@ -206,10 +219,11 @@ class Parser:
break
return pos
# Throw away the start of the string. Intended to be called with
# find_good_parse_start's result.
def set_lo(self, lo):
""" Throw away the start of the string.
Intended to be called with the result of find_good_parse_start().
"""
assert lo == 0 or self.str[lo-1] == '\n'
if lo > 0:
self.str = self.str[lo:]
@ -224,11 +238,13 @@ class Parser:
_tran.update((ord(c), ord(c)) for c in "\"'\\\n#")
_tran = StringTranslatePseudoMapping(_tran, default_value=ord('x'))
# As quickly as humanly possible <wink>, find the line numbers (0-
# based) of the non-continuation lines.
# Creates self.{goodlines, continuation}.
def _study1(self):
"""Find the line numbers of non-continuation lines.
As quickly as humanly possible <wink>, find the line numbers (0-
based) of the non-continuation lines.
Creates self.{goodlines, continuation}.
"""
if self.study_level >= 1:
return
self.study_level = 1
@ -244,8 +260,8 @@ class Parser:
str = str.replace('xx', 'x')
str = str.replace('xx', 'x')
str = str.replace('\nx', '\n')
# note that replacing x\n with \n would be incorrect, because
# x may be preceded by a backslash
# Replacing x\n with \n would be incorrect because
# x may be preceded by a backslash.
# March over the squashed version of the program, accumulating
# the line numbers of non-continued stmts, and determining
@ -360,24 +376,25 @@ class Parser:
self._study1()
return self.continuation
# study1 was sufficient to determine the continuation status,
# but doing more requires looking at every character. study2
# does this for the last interesting statement in the block.
# Creates:
# self.stmt_start, stmt_end
# slice indices of last interesting stmt
# self.stmt_bracketing
# the bracketing structure of the last interesting stmt;
# for example, for the statement "say(boo) or die", stmt_bracketing
# will be [(0, 0), (3, 1), (8, 0)]. Strings and comments are
# treated as brackets, for the matter.
# self.lastch
# last non-whitespace character before optional trailing
# comment
# self.lastopenbracketpos
# if continuation is C_BRACKET, index of last open bracket
def _study2(self):
"""
study1 was sufficient to determine the continuation status,
but doing more requires looking at every character. study2
does this for the last interesting statement in the block.
Creates:
self.stmt_start, stmt_end
slice indices of last interesting stmt
self.stmt_bracketing
the bracketing structure of the last interesting stmt; for
example, for the statement "say(boo) or die",
stmt_bracketing will be ((0, 0), (0, 1), (2, 0), (2, 1),
(4, 0)). Strings and comments are treated as brackets, for
the matter.
self.lastch
last interesting character before optional trailing comment
self.lastopenbracketpos
if continuation is C_BRACKET, index of last open bracket
"""
if self.study_level >= 2:
return
self._study1()
@ -385,11 +402,11 @@ class Parser:
# Set p and q to slice indices of last interesting stmt.
str, goodlines = self.str, self.goodlines
i = len(goodlines) - 1
p = len(str) # index of newest line
i = len(goodlines) - 1 # Index of newest line.
p = len(str) # End of goodlines[i]
while i:
assert p
# p is the index of the stmt at line number goodlines[i].
# Make p be the index of the stmt at line number goodlines[i].
# Move p back to the stmt at line number goodlines[i-1].
q = p
for nothing in range(goodlines[i-1], goodlines[i]):
@ -483,10 +500,11 @@ class Parser:
self.lastopenbracketpos = stack[-1]
self.stmt_bracketing = tuple(bracketing)
# Assuming continuation is C_BRACKET, return the number
# of spaces the next line should be indented.
def compute_bracket_indent(self):
"""Return number of spaces the next line should be indented.
Line continuation must be C_BRACKET.
"""
self._study2()
assert self.continuation == C_BRACKET
j = self.lastopenbracketpos
@ -513,20 +531,22 @@ class Parser:
extra = self.indentwidth
return len(str[i:j].expandtabs(self.tabwidth)) + extra
# Return number of physical lines in last stmt (whether or not
# it's an interesting stmt! this is intended to be called when
# continuation is C_BACKSLASH).
def get_num_lines_in_stmt(self):
"""Return number of physical lines in last stmt.
The statement doesn't have to be an interesting statement. This is
intended to be called when continuation is C_BACKSLASH.
"""
self._study1()
goodlines = self.goodlines
return goodlines[-1] - goodlines[-2]
# Assuming continuation is C_BACKSLASH, return the number of spaces
# the next line should be indented. Also assuming the new line is
# the first one following the initial line of the stmt.
def compute_backslash_indent(self):
"""Return number of spaces the next line should be indented.
Line continuation must be C_BACKSLASH. Also assume that the new
line is the first one following the initial line of the stmt.
"""
self._study2()
assert self.continuation == C_BACKSLASH
str = self.str
@ -551,6 +571,8 @@ class Parser:
elif ch == '"' or ch == "'":
i = _match_stringre(str, i, endpos).end()
elif ch == '#':
# This line is unreachable because the # makes a comment of
# everything after it.
break
elif level == 0 and ch == '=' and \
(i == 0 or str[i-1] not in "=<>!") and \
@ -576,10 +598,10 @@ class Parser:
return len(str[self.stmt_start:i].expandtabs(\
self.tabwidth)) + 1
# Return the leading whitespace on the initial line of the last
# interesting stmt.
def get_base_indent_string(self):
"""Return the leading whitespace on the initial line of the last
interesting stmt.
"""
self._study2()
i, n = self.stmt_start, self.stmt_end
j = i
@ -588,30 +610,37 @@ class Parser:
j = j + 1
return str[i:j]
# Did the last interesting stmt open a block?
def is_block_opener(self):
"Return True if the last interesting statemtent opens a block."
self._study2()
return self.lastch == ':'
# Did the last interesting stmt close a block?
def is_block_closer(self):
"Return True if the last interesting statement closes a block."
self._study2()
return _closere(self.str, self.stmt_start) is not None
# index of last open bracket ({[, or None if none
# XXX - is this used?
lastopenbracketpos = None
def get_last_open_bracket_pos(self):
"Return index of last open bracket or None."
self._study2()
return self.lastopenbracketpos
# the structure of the bracketing of the last interesting statement,
# in the format defined in _study2, or None if the text didn't contain
# anything
# XXX - is this used?
stmt_bracketing = None
def get_last_stmt_bracketing(self):
"""Return a tuple of the structure of the bracketing of the last
interesting statement.
Tuple is in the format defined in _study2().
"""
self._study2()
return self.stmt_bracketing
if __name__ == '__main__': #pragma: nocover
import unittest
unittest.main('idlelib.idle_test.test_pyparse', verbosity=2)