| # mako/pygen.py |
| # Copyright (C) 2006-2015 the Mako authors and contributors <see AUTHORS file> |
| # |
| # This module is part of Mako and is released under |
| # the MIT License: http://www.opensource.org/licenses/mit-license.php |
| |
| """utilities for generating and formatting literal Python code.""" |
| |
| import re |
| from mako import exceptions |
| |
| |
| class PythonPrinter(object): |
| |
| def __init__(self, stream): |
| # indentation counter |
| self.indent = 0 |
| |
| # a stack storing information about why we incremented |
| # the indentation counter, to help us determine if we |
| # should decrement it |
| self.indent_detail = [] |
| |
| # the string of whitespace multiplied by the indent |
| # counter to produce a line |
| self.indentstring = " " |
| |
| # the stream we are writing to |
| self.stream = stream |
| |
| # current line number |
| self.lineno = 1 |
| |
| # a list of lines that represents a buffered "block" of code, |
| # which can be later printed relative to an indent level |
| self.line_buffer = [] |
| |
| self.in_indent_lines = False |
| |
| self._reset_multi_line_flags() |
| |
| # mapping of generated python lines to template |
| # source lines |
| self.source_map = {} |
| |
| def _update_lineno(self, num): |
| self.lineno += num |
| |
| def start_source(self, lineno): |
| if self.lineno not in self.source_map: |
| self.source_map[self.lineno] = lineno |
| |
| def write_blanks(self, num): |
| self.stream.write("\n" * num) |
| self._update_lineno(num) |
| |
| def write_indented_block(self, block): |
| """print a line or lines of python which already contain indentation. |
| |
| The indentation of the total block of lines will be adjusted to that of |
| the current indent level.""" |
| self.in_indent_lines = False |
| for l in re.split(r'\r?\n', block): |
| self.line_buffer.append(l) |
| self._update_lineno(1) |
| |
| def writelines(self, *lines): |
| """print a series of lines of python.""" |
| for line in lines: |
| self.writeline(line) |
| |
| def writeline(self, line): |
| """print a line of python, indenting it according to the current |
| indent level. |
| |
| this also adjusts the indentation counter according to the |
| content of the line. |
| |
| """ |
| |
| if not self.in_indent_lines: |
| self._flush_adjusted_lines() |
| self.in_indent_lines = True |
| |
| if ( |
| line is None or |
| re.match(r"^\s*#", line) or |
| re.match(r"^\s*$", line) |
| ): |
| hastext = False |
| else: |
| hastext = True |
| |
| is_comment = line and len(line) and line[0] == '#' |
| |
| # see if this line should decrease the indentation level |
| if ( |
| not is_comment and |
| (not hastext or self._is_unindentor(line)) |
| ): |
| |
| if self.indent > 0: |
| self.indent -= 1 |
| # if the indent_detail stack is empty, the user |
| # probably put extra closures - the resulting |
| # module wont compile. |
| if len(self.indent_detail) == 0: |
| raise exceptions.SyntaxException( |
| "Too many whitespace closures") |
| self.indent_detail.pop() |
| |
| if line is None: |
| return |
| |
| # write the line |
| self.stream.write(self._indent_line(line) + "\n") |
| self._update_lineno(len(line.split("\n"))) |
| |
| # see if this line should increase the indentation level. |
| # note that a line can both decrase (before printing) and |
| # then increase (after printing) the indentation level. |
| |
| if re.search(r":[ \t]*(?:#.*)?$", line): |
| # increment indentation count, and also |
| # keep track of what the keyword was that indented us, |
| # if it is a python compound statement keyword |
| # where we might have to look for an "unindent" keyword |
| match = re.match(r"^\s*(if|try|elif|while|for|with)", line) |
| if match: |
| # its a "compound" keyword, so we will check for "unindentors" |
| indentor = match.group(1) |
| self.indent += 1 |
| self.indent_detail.append(indentor) |
| else: |
| indentor = None |
| # its not a "compound" keyword. but lets also |
| # test for valid Python keywords that might be indenting us, |
| # else assume its a non-indenting line |
| m2 = re.match(r"^\s*(def|class|else|elif|except|finally)", |
| line) |
| if m2: |
| self.indent += 1 |
| self.indent_detail.append(indentor) |
| |
| def close(self): |
| """close this printer, flushing any remaining lines.""" |
| self._flush_adjusted_lines() |
| |
| def _is_unindentor(self, line): |
| """return true if the given line is an 'unindentor', |
| relative to the last 'indent' event received. |
| |
| """ |
| |
| # no indentation detail has been pushed on; return False |
| if len(self.indent_detail) == 0: |
| return False |
| |
| indentor = self.indent_detail[-1] |
| |
| # the last indent keyword we grabbed is not a |
| # compound statement keyword; return False |
| if indentor is None: |
| return False |
| |
| # if the current line doesnt have one of the "unindentor" keywords, |
| # return False |
| match = re.match(r"^\s*(else|elif|except|finally).*\:", line) |
| if not match: |
| return False |
| |
| # whitespace matches up, we have a compound indentor, |
| # and this line has an unindentor, this |
| # is probably good enough |
| return True |
| |
| # should we decide that its not good enough, heres |
| # more stuff to check. |
| # keyword = match.group(1) |
| |
| # match the original indent keyword |
| # for crit in [ |
| # (r'if|elif', r'else|elif'), |
| # (r'try', r'except|finally|else'), |
| # (r'while|for', r'else'), |
| # ]: |
| # if re.match(crit[0], indentor) and re.match(crit[1], keyword): |
| # return True |
| |
| # return False |
| |
| def _indent_line(self, line, stripspace=''): |
| """indent the given line according to the current indent level. |
| |
| stripspace is a string of space that will be truncated from the |
| start of the line before indenting.""" |
| |
| return re.sub(r"^%s" % stripspace, self.indentstring |
| * self.indent, line) |
| |
| def _reset_multi_line_flags(self): |
| """reset the flags which would indicate we are in a backslashed |
| or triple-quoted section.""" |
| |
| self.backslashed, self.triplequoted = False, False |
| |
| def _in_multi_line(self, line): |
| """return true if the given line is part of a multi-line block, |
| via backslash or triple-quote.""" |
| |
| # we are only looking for explicitly joined lines here, not |
| # implicit ones (i.e. brackets, braces etc.). this is just to |
| # guard against the possibility of modifying the space inside of |
| # a literal multiline string with unfortunately placed |
| # whitespace |
| |
| current_state = (self.backslashed or self.triplequoted) |
| |
| if re.search(r"\\$", line): |
| self.backslashed = True |
| else: |
| self.backslashed = False |
| |
| triples = len(re.findall(r"\"\"\"|\'\'\'", line)) |
| if triples == 1 or triples % 2 != 0: |
| self.triplequoted = not self.triplequoted |
| |
| return current_state |
| |
| def _flush_adjusted_lines(self): |
| stripspace = None |
| self._reset_multi_line_flags() |
| |
| for entry in self.line_buffer: |
| if self._in_multi_line(entry): |
| self.stream.write(entry + "\n") |
| else: |
| entry = entry.expandtabs() |
| if stripspace is None and re.search(r"^[ \t]*[^# \t]", entry): |
| stripspace = re.match(r"^([ \t]*)", entry).group(1) |
| self.stream.write(self._indent_line(entry, stripspace) + "\n") |
| |
| self.line_buffer = [] |
| self._reset_multi_line_flags() |
| |
| |
| def adjust_whitespace(text): |
| """remove the left-whitespace margin of a block of Python code.""" |
| |
| state = [False, False] |
| (backslashed, triplequoted) = (0, 1) |
| |
| def in_multi_line(line): |
| start_state = (state[backslashed] or state[triplequoted]) |
| |
| if re.search(r"\\$", line): |
| state[backslashed] = True |
| else: |
| state[backslashed] = False |
| |
| def match(reg, t): |
| m = re.match(reg, t) |
| if m: |
| return m, t[len(m.group(0)):] |
| else: |
| return None, t |
| |
| while line: |
| if state[triplequoted]: |
| m, line = match(r"%s" % state[triplequoted], line) |
| if m: |
| state[triplequoted] = False |
| else: |
| m, line = match(r".*?(?=%s|$)" % state[triplequoted], line) |
| else: |
| m, line = match(r'#', line) |
| if m: |
| return start_state |
| |
| m, line = match(r"\"\"\"|\'\'\'", line) |
| if m: |
| state[triplequoted] = m.group(0) |
| continue |
| |
| m, line = match(r".*?(?=\"\"\"|\'\'\'|#|$)", line) |
| |
| return start_state |
| |
| def _indent_line(line, stripspace=''): |
| return re.sub(r"^%s" % stripspace, '', line) |
| |
| lines = [] |
| stripspace = None |
| |
| for line in re.split(r'\r?\n', text): |
| if in_multi_line(line): |
| lines.append(line) |
| else: |
| line = line.expandtabs() |
| if stripspace is None and re.search(r"^[ \t]*[^# \t]", line): |
| stripspace = re.match(r"^([ \t]*)", line).group(1) |
| lines.append(_indent_line(line, stripspace)) |
| return "\n".join(lines) |
