mirror of
https://github.com/python/cpython.git
synced 2024-11-21 21:09:37 +01:00
590 lines
19 KiB
Python
590 lines
19 KiB
Python
"""Define partial Python code Parser used by editor and hyperparser.
|
|
|
|
Instances of ParseMap 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.
|
|
"""
|
|
import re
|
|
|
|
# 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)
|
|
|
|
# Find what looks like the start of a popular statement.
|
|
|
|
_synchre = re.compile(r"""
|
|
^
|
|
[ \t]*
|
|
(?: while
|
|
| else
|
|
| def
|
|
| return
|
|
| assert
|
|
| break
|
|
| class
|
|
| continue
|
|
| elif
|
|
| try
|
|
| except
|
|
| raise
|
|
| import
|
|
| yield
|
|
)
|
|
\b
|
|
""", re.VERBOSE | re.MULTILINE).search
|
|
|
|
# Match blank line or non-indenting comment line.
|
|
|
|
_junkre = re.compile(r"""
|
|
[ \t]*
|
|
(?: \# \S .* )?
|
|
\n
|
|
""", re.VERBOSE).match
|
|
|
|
# Match any flavor of string; the terminating quote is optional
|
|
# so that we're robust in the face of incomplete program text.
|
|
|
|
_match_stringre = re.compile(r"""
|
|
\""" [^"\\]* (?:
|
|
(?: \\. | "(?!"") )
|
|
[^"\\]*
|
|
)*
|
|
(?: \""" )?
|
|
|
|
| " [^"\\\n]* (?: \\. [^"\\\n]* )* "?
|
|
|
|
| ''' [^'\\]* (?:
|
|
(?: \\. | '(?!'') )
|
|
[^'\\]*
|
|
)*
|
|
(?: ''' )?
|
|
|
|
| ' [^'\\\n]* (?: \\. [^'\\\n]* )* '?
|
|
""", re.VERBOSE | re.DOTALL).match
|
|
|
|
# Match a line that starts with something interesting;
|
|
# used to find the first item of a bracket structure.
|
|
|
|
_itemre = re.compile(r"""
|
|
[ \t]*
|
|
[^\s#\\] # if we match, m.end()-1 is the interesting char
|
|
""", re.VERBOSE).match
|
|
|
|
# Match start of statements that should be followed by a dedent.
|
|
|
|
_closere = re.compile(r"""
|
|
\s*
|
|
(?: return
|
|
| break
|
|
| continue
|
|
| raise
|
|
| pass
|
|
)
|
|
\b
|
|
""", re.VERBOSE).match
|
|
|
|
# Chew up non-special chars as quickly as possible. If match is
|
|
# successful, m.end() less 1 is the index of the last boring char
|
|
# matched. If match is unsuccessful, the string starts with an
|
|
# interesting char.
|
|
|
|
_chew_ordinaryre = re.compile(r"""
|
|
[^[\](){}#'"\\]+
|
|
""", re.VERBOSE).match
|
|
|
|
|
|
class ParseMap(dict):
|
|
r"""Dict subclass that maps anything not in dict to 'x'.
|
|
|
|
This is designed to be used with str.translate in study1.
|
|
Anything not specifically mapped otherwise becomes 'x'.
|
|
Example: replace everything except whitespace with 'x'.
|
|
|
|
>>> keepwhite = ParseMap((ord(c), ord(c)) for c in ' \t\n\r')
|
|
>>> "a + b\tc\nd".translate(keepwhite)
|
|
'x x x\tx\nx'
|
|
"""
|
|
# Calling this triples access time; see bpo-32940
|
|
def __missing__(self, key):
|
|
return 120 # ord('x')
|
|
|
|
|
|
# Map all ascii to 120 to avoid __missing__ call, then replace some.
|
|
trans = ParseMap.fromkeys(range(128), 120)
|
|
trans.update((ord(c), ord('(')) for c in "({[") # open brackets => '(';
|
|
trans.update((ord(c), ord(')')) for c in ")}]") # close brackets => ')'.
|
|
trans.update((ord(c), ord(c)) for c in "\"'\\\n#") # Keep these.
|
|
|
|
|
|
class Parser:
|
|
|
|
def __init__(self, indentwidth, tabwidth):
|
|
self.indentwidth = indentwidth
|
|
self.tabwidth = tabwidth
|
|
|
|
def set_code(self, s):
|
|
assert len(s) == 0 or s[-1] == '\n'
|
|
self.code = s
|
|
self.study_level = 0
|
|
|
|
def find_good_parse_start(self, is_char_in_string):
|
|
"""
|
|
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.
|
|
"""
|
|
code, pos = self.code, None
|
|
|
|
# Peek back from the end for a good place to start,
|
|
# but don't try too often; pos will be left None, or
|
|
# bumped to a legitimate synch point.
|
|
limit = len(code)
|
|
for tries in range(5):
|
|
i = code.rfind(":\n", 0, limit)
|
|
if i < 0:
|
|
break
|
|
i = code.rfind('\n', 0, i) + 1 # start of colon line (-1+1=0)
|
|
m = _synchre(code, i, limit)
|
|
if m and not is_char_in_string(m.start()):
|
|
pos = m.start()
|
|
break
|
|
limit = i
|
|
if pos is None:
|
|
# Nothing looks like a block-opener, or stuff does
|
|
# but is_char_in_string keeps returning true; most likely
|
|
# we're in or near a giant string, the colorizer hasn't
|
|
# caught up enough to be helpful, or there simply *aren't*
|
|
# any interesting stmts. In any of these cases we're
|
|
# going to have to parse the whole thing to be sure, so
|
|
# give it one last try from the start, but stop wasting
|
|
# time here regardless of the outcome.
|
|
m = _synchre(code)
|
|
if m and not is_char_in_string(m.start()):
|
|
pos = m.start()
|
|
return pos
|
|
|
|
# Peeking back worked; look forward until _synchre no longer
|
|
# matches.
|
|
i = pos + 1
|
|
while m := _synchre(code, i):
|
|
s, i = m.span()
|
|
if not is_char_in_string(s):
|
|
pos = s
|
|
return pos
|
|
|
|
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.code[lo-1] == '\n'
|
|
if lo > 0:
|
|
self.code = self.code[lo:]
|
|
|
|
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
|
|
|
|
# Map all uninteresting characters to "x", all open brackets
|
|
# to "(", all close brackets to ")", then collapse runs of
|
|
# uninteresting characters. This can cut the number of chars
|
|
# by a factor of 10-40, and so greatly speed the following loop.
|
|
code = self.code
|
|
code = code.translate(trans)
|
|
code = code.replace('xxxxxxxx', 'x')
|
|
code = code.replace('xxxx', 'x')
|
|
code = code.replace('xx', 'x')
|
|
code = code.replace('xx', 'x')
|
|
code = code.replace('\nx', '\n')
|
|
# 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
|
|
# whether & why the last stmt is a continuation.
|
|
continuation = C_NONE
|
|
level = lno = 0 # level is nesting level; lno is line number
|
|
self.goodlines = goodlines = [0]
|
|
push_good = goodlines.append
|
|
i, n = 0, len(code)
|
|
while i < n:
|
|
ch = code[i]
|
|
i = i+1
|
|
|
|
# cases are checked in decreasing order of frequency
|
|
if ch == 'x':
|
|
continue
|
|
|
|
if ch == '\n':
|
|
lno = lno + 1
|
|
if level == 0:
|
|
push_good(lno)
|
|
# else we're in an unclosed bracket structure
|
|
continue
|
|
|
|
if ch == '(':
|
|
level = level + 1
|
|
continue
|
|
|
|
if ch == ')':
|
|
if level:
|
|
level = level - 1
|
|
# else the program is invalid, but we can't complain
|
|
continue
|
|
|
|
if ch == '"' or ch == "'":
|
|
# consume the string
|
|
quote = ch
|
|
if code[i-1:i+2] == quote * 3:
|
|
quote = quote * 3
|
|
firstlno = lno
|
|
w = len(quote) - 1
|
|
i = i+w
|
|
while i < n:
|
|
ch = code[i]
|
|
i = i+1
|
|
|
|
if ch == 'x':
|
|
continue
|
|
|
|
if code[i-1:i+w] == quote:
|
|
i = i+w
|
|
break
|
|
|
|
if ch == '\n':
|
|
lno = lno + 1
|
|
if w == 0:
|
|
# unterminated single-quoted string
|
|
if level == 0:
|
|
push_good(lno)
|
|
break
|
|
continue
|
|
|
|
if ch == '\\':
|
|
assert i < n
|
|
if code[i] == '\n':
|
|
lno = lno + 1
|
|
i = i+1
|
|
continue
|
|
|
|
# else comment char or paren inside string
|
|
|
|
else:
|
|
# didn't break out of the loop, so we're still
|
|
# inside a string
|
|
if (lno - 1) == firstlno:
|
|
# before the previous \n in code, we were in the first
|
|
# line of the string
|
|
continuation = C_STRING_FIRST_LINE
|
|
else:
|
|
continuation = C_STRING_NEXT_LINES
|
|
continue # with outer loop
|
|
|
|
if ch == '#':
|
|
# consume the comment
|
|
i = code.find('\n', i)
|
|
assert i >= 0
|
|
continue
|
|
|
|
assert ch == '\\'
|
|
assert i < n
|
|
if code[i] == '\n':
|
|
lno = lno + 1
|
|
if i+1 == n:
|
|
continuation = C_BACKSLASH
|
|
i = i+1
|
|
|
|
# The last stmt may be continued for all 3 reasons.
|
|
# String continuation takes precedence over bracket
|
|
# continuation, which beats backslash continuation.
|
|
if (continuation != C_STRING_FIRST_LINE
|
|
and continuation != C_STRING_NEXT_LINES and level > 0):
|
|
continuation = C_BRACKET
|
|
self.continuation = continuation
|
|
|
|
# Push the final line number as a sentinel value, regardless of
|
|
# whether it's continued.
|
|
assert (continuation == C_NONE) == (goodlines[-1] == lno)
|
|
if goodlines[-1] != lno:
|
|
push_good(lno)
|
|
|
|
def get_continuation_type(self):
|
|
self._study1()
|
|
return self.continuation
|
|
|
|
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()
|
|
self.study_level = 2
|
|
|
|
# Set p and q to slice indices of last interesting stmt.
|
|
code, goodlines = self.code, self.goodlines
|
|
i = len(goodlines) - 1 # Index of newest line.
|
|
p = len(code) # End of goodlines[i]
|
|
while i:
|
|
assert p
|
|
# 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]):
|
|
# tricky: sets p to 0 if no preceding newline
|
|
p = code.rfind('\n', 0, p-1) + 1
|
|
# The stmt code[p:q] isn't a continuation, but may be blank
|
|
# or a non-indenting comment line.
|
|
if _junkre(code, p):
|
|
i = i-1
|
|
else:
|
|
break
|
|
if i == 0:
|
|
# nothing but junk!
|
|
assert p == 0
|
|
q = p
|
|
self.stmt_start, self.stmt_end = p, q
|
|
|
|
# Analyze this stmt, to find the last open bracket (if any)
|
|
# and last interesting character (if any).
|
|
lastch = ""
|
|
stack = [] # stack of open bracket indices
|
|
push_stack = stack.append
|
|
bracketing = [(p, 0)]
|
|
while p < q:
|
|
# suck up all except ()[]{}'"#\\
|
|
m = _chew_ordinaryre(code, p, q)
|
|
if m:
|
|
# we skipped at least one boring char
|
|
newp = m.end()
|
|
# back up over totally boring whitespace
|
|
i = newp - 1 # index of last boring char
|
|
while i >= p and code[i] in " \t\n":
|
|
i = i-1
|
|
if i >= p:
|
|
lastch = code[i]
|
|
p = newp
|
|
if p >= q:
|
|
break
|
|
|
|
ch = code[p]
|
|
|
|
if ch in "([{":
|
|
push_stack(p)
|
|
bracketing.append((p, len(stack)))
|
|
lastch = ch
|
|
p = p+1
|
|
continue
|
|
|
|
if ch in ")]}":
|
|
if stack:
|
|
del stack[-1]
|
|
lastch = ch
|
|
p = p+1
|
|
bracketing.append((p, len(stack)))
|
|
continue
|
|
|
|
if ch == '"' or ch == "'":
|
|
# consume string
|
|
# Note that study1 did this with a Python loop, but
|
|
# we use a regexp here; the reason is speed in both
|
|
# cases; the string may be huge, but study1 pre-squashed
|
|
# strings to a couple of characters per line. study1
|
|
# also needed to keep track of newlines, and we don't
|
|
# have to.
|
|
bracketing.append((p, len(stack)+1))
|
|
lastch = ch
|
|
p = _match_stringre(code, p, q).end()
|
|
bracketing.append((p, len(stack)))
|
|
continue
|
|
|
|
if ch == '#':
|
|
# consume comment and trailing newline
|
|
bracketing.append((p, len(stack)+1))
|
|
p = code.find('\n', p, q) + 1
|
|
assert p > 0
|
|
bracketing.append((p, len(stack)))
|
|
continue
|
|
|
|
assert ch == '\\'
|
|
p = p+1 # beyond backslash
|
|
assert p < q
|
|
if code[p] != '\n':
|
|
# the program is invalid, but can't complain
|
|
lastch = ch + code[p]
|
|
p = p+1 # beyond escaped char
|
|
|
|
# end while p < q:
|
|
|
|
self.lastch = lastch
|
|
self.lastopenbracketpos = stack[-1] if stack else None
|
|
self.stmt_bracketing = tuple(bracketing)
|
|
|
|
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
|
|
code = self.code
|
|
n = len(code)
|
|
origi = i = code.rfind('\n', 0, j) + 1
|
|
j = j+1 # one beyond open bracket
|
|
# find first list item; set i to start of its line
|
|
while j < n:
|
|
m = _itemre(code, j)
|
|
if m:
|
|
j = m.end() - 1 # index of first interesting char
|
|
extra = 0
|
|
break
|
|
else:
|
|
# this line is junk; advance to next line
|
|
i = j = code.find('\n', j) + 1
|
|
else:
|
|
# nothing interesting follows the bracket;
|
|
# reproduce the bracket line's indentation + a level
|
|
j = i = origi
|
|
while code[j] in " \t":
|
|
j = j+1
|
|
extra = self.indentwidth
|
|
return len(code[i:j].expandtabs(self.tabwidth)) + extra
|
|
|
|
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]
|
|
|
|
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
|
|
code = self.code
|
|
i = self.stmt_start
|
|
while code[i] in " \t":
|
|
i = i+1
|
|
startpos = i
|
|
|
|
# See whether the initial line starts an assignment stmt; i.e.,
|
|
# look for an = operator
|
|
endpos = code.find('\n', startpos) + 1
|
|
found = level = 0
|
|
while i < endpos:
|
|
ch = code[i]
|
|
if ch in "([{":
|
|
level = level + 1
|
|
i = i+1
|
|
elif ch in ")]}":
|
|
if level:
|
|
level = level - 1
|
|
i = i+1
|
|
elif ch == '"' or ch == "'":
|
|
i = _match_stringre(code, 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 code[i-1] not in "=<>!") and \
|
|
code[i+1] != '=':
|
|
found = 1
|
|
break
|
|
else:
|
|
i = i+1
|
|
|
|
if found:
|
|
# found a legit =, but it may be the last interesting
|
|
# thing on the line
|
|
i = i+1 # move beyond the =
|
|
found = re.match(r"\s*\\", code[i:endpos]) is None
|
|
|
|
if not found:
|
|
# oh well ... settle for moving beyond the first chunk
|
|
# of non-whitespace chars
|
|
i = startpos
|
|
while code[i] not in " \t\n":
|
|
i = i+1
|
|
|
|
return len(code[self.stmt_start:i].expandtabs(\
|
|
self.tabwidth)) + 1
|
|
|
|
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
|
|
code = self.code
|
|
while j < n and code[j] in " \t":
|
|
j = j + 1
|
|
return code[i:j]
|
|
|
|
def is_block_opener(self):
|
|
"Return True if the last interesting statement opens a block."
|
|
self._study2()
|
|
return self.lastch == ':'
|
|
|
|
def is_block_closer(self):
|
|
"Return True if the last interesting statement closes a block."
|
|
self._study2()
|
|
return _closere(self.code, self.stmt_start) is not None
|
|
|
|
def get_last_stmt_bracketing(self):
|
|
"""Return bracketing structure of the last interesting statement.
|
|
|
|
The returned tuple is in the format defined in _study2().
|
|
"""
|
|
self._study2()
|
|
return self.stmt_bracketing
|
|
|
|
|
|
if __name__ == '__main__':
|
|
from unittest import main
|
|
main('idlelib.idle_test.test_pyparse', verbosity=2)
|