| import re |
| import sys |
| |
| # Reason last stmt 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) |
| |
| 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. |
| |
| _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 stmts 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 |
| |
| # Build translation table to map uninteresting chars to "x", open |
| # brackets to "(", and close brackets to ")". |
| |
| _tran = ['x'] * 256 |
| for ch in "({[": |
| _tran[ord(ch)] = '(' |
| for ch in ")}]": |
| _tran[ord(ch)] = ')' |
| for ch in "\"'\\\n#": |
| _tran[ord(ch)] = ch |
| _tran = ''.join(_tran) |
| del ch |
| |
| try: |
| UnicodeType = type(unicode("")) |
| except NameError: |
| UnicodeType = None |
| |
| class Parser: |
| |
| def __init__(self, indentwidth, tabwidth): |
| self.indentwidth = indentwidth |
| self.tabwidth = tabwidth |
| |
| def set_str(self, str): |
| assert len(str) == 0 or str[-1] == '\n' |
| if type(str) is UnicodeType: |
| # The parse functions have no idea what to do with Unicode, so |
| # replace all Unicode characters with "x". This is "safe" |
| # so long as the only characters germane to parsing the structure |
| # of Python are 7-bit ASCII. It's *necessary* because Unicode |
| # strings don't have a .translate() method that supports |
| # deletechars. |
| uniphooey = str |
| str = [] |
| push = str.append |
| for raw in map(ord, uniphooey): |
| push(raw < 127 and chr(raw) or "x") |
| str = "".join(str) |
| self.str = str |
| 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): |
| str, pos = self.str, None |
| |
| if not is_char_in_string: |
| # no clue -- make the caller pass everything |
| return 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(str) |
| for tries in range(5): |
| i = str.rfind(":\n", 0, limit) |
| if i < 0: |
| break |
| i = str.rfind('\n', 0, i) + 1 # start of colon line |
| m = _synchre(str, 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(str) |
| 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 1: |
| m = _synchre(str, i) |
| if m: |
| s, i = m.span() |
| if not is_char_in_string(s): |
| pos = s |
| else: |
| 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): |
| assert lo == 0 or self.str[lo-1] == '\n' |
| if lo > 0: |
| self.str = self.str[lo:] |
| |
| # As quickly as humanly possible <wink>, find the line numbers (0- |
| # based) of the non-continuation lines. |
| # Creates self.{goodlines, continuation}. |
| |
| def _study1(self): |
| 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. |
| str = self.str |
| str = str.translate(_tran) |
| str = str.replace('xxxxxxxx', 'x') |
| str = str.replace('xxxx', 'x') |
| 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 |
| |
| # 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(str) |
| while i < n: |
| ch = str[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 str[i-1:i+2] == quote * 3: |
| quote = quote * 3 |
| firstlno = lno |
| w = len(quote) - 1 |
| i = i+w |
| while i < n: |
| ch = str[i] |
| i = i+1 |
| |
| if ch == 'x': |
| continue |
| |
| if str[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 str[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 str, 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 = str.find('\n', i) |
| assert i >= 0 |
| continue |
| |
| assert ch == '\\' |
| assert i < n |
| if str[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 |
| |
| # 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): |
| if self.study_level >= 2: |
| return |
| self._study1() |
| self.study_level = 2 |
| |
| # 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 |
| while i: |
| assert p |
| # p is 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 = str.rfind('\n', 0, p-1) + 1 |
| # The stmt str[p:q] isn't a continuation, but may be blank |
| # or a non-indenting comment line. |
| if _junkre(str, 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(str, 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 str[i] in " \t\n": |
| i = i-1 |
| if i >= p: |
| lastch = str[i] |
| p = newp |
| if p >= q: |
| break |
| |
| ch = str[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(str, p, q).end() |
| bracketing.append((p, len(stack))) |
| continue |
| |
| if ch == '#': |
| # consume comment and trailing newline |
| bracketing.append((p, len(stack)+1)) |
| p = str.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 str[p] != '\n': |
| # the program is invalid, but can't complain |
| lastch = ch + str[p] |
| p = p+1 # beyond escaped char |
| |
| # end while p < q: |
| |
| self.lastch = lastch |
| if stack: |
| 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): |
| self._study2() |
| assert self.continuation == C_BRACKET |
| j = self.lastopenbracketpos |
| str = self.str |
| n = len(str) |
| origi = i = str.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(str, 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 = str.find('\n', j) + 1 |
| else: |
| # nothing interesting follows the bracket; |
| # reproduce the bracket line's indentation + a level |
| j = i = origi |
| while str[j] in " \t": |
| j = j+1 |
| 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): |
| 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): |
| self._study2() |
| assert self.continuation == C_BACKSLASH |
| str = self.str |
| i = self.stmt_start |
| while str[i] in " \t": |
| i = i+1 |
| startpos = i |
| |
| # See whether the initial line starts an assignment stmt; i.e., |
| # look for an = operator |
| endpos = str.find('\n', startpos) + 1 |
| found = level = 0 |
| while i < endpos: |
| ch = str[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(str, i, endpos).end() |
| elif ch == '#': |
| break |
| elif level == 0 and ch == '=' and \ |
| (i == 0 or str[i-1] not in "=<>!") and \ |
| str[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*\\", str[i:endpos]) is None |
| |
| if not found: |
| # oh well ... settle for moving beyond the first chunk |
| # of non-whitespace chars |
| i = startpos |
| while str[i] not in " \t\n": |
| i = i+1 |
| |
| 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): |
| self._study2() |
| i, n = self.stmt_start, self.stmt_end |
| j = i |
| str = self.str |
| while j < n and str[j] in " \t": |
| j = j + 1 |
| return str[i:j] |
| |
| # Did the last interesting stmt open a block? |
| |
| def is_block_opener(self): |
| self._study2() |
| return self.lastch == ':' |
| |
| # Did the last interesting stmt close a block? |
| |
| def is_block_closer(self): |
| self._study2() |
| return _closere(self.str, self.stmt_start) is not None |
| |
| # index of last open bracket ({[, or None if none |
| lastopenbracketpos = None |
| |
| def get_last_open_bracket_pos(self): |
| 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 |
| stmt_bracketing = None |
| |
| def get_last_stmt_bracketing(self): |
| self._study2() |
| return self.stmt_bracketing |
