| #! /usr/bin/env python3 |
| |
| # This file contains a class and a main program that perform three |
| # related (though complimentary) formatting operations on Python |
| # programs. When called as "pindent -c", it takes a valid Python |
| # program as input and outputs a version augmented with block-closing |
| # comments. When called as "pindent -d", it assumes its input is a |
| # Python program with block-closing comments and outputs a commentless |
| # version. When called as "pindent -r" it assumes its input is a |
| # Python program with block-closing comments but with its indentation |
| # messed up, and outputs a properly indented version. |
| |
| # A "block-closing comment" is a comment of the form '# end <keyword>' |
| # where <keyword> is the keyword that opened the block. If the |
| # opening keyword is 'def' or 'class', the function or class name may |
| # be repeated in the block-closing comment as well. Here is an |
| # example of a program fully augmented with block-closing comments: |
| |
| # def foobar(a, b): |
| # if a == b: |
| # a = a+1 |
| # elif a < b: |
| # b = b-1 |
| # if b > a: a = a-1 |
| # # end if |
| # else: |
| # print 'oops!' |
| # # end if |
| # # end def foobar |
| |
| # Note that only the last part of an if...elif...else... block needs a |
| # block-closing comment; the same is true for other compound |
| # statements (e.g. try...except). Also note that "short-form" blocks |
| # like the second 'if' in the example must be closed as well; |
| # otherwise the 'else' in the example would be ambiguous (remember |
| # that indentation is not significant when interpreting block-closing |
| # comments). |
| |
| # The operations are idempotent (i.e. applied to their own output |
| # they yield an identical result). Running first "pindent -c" and |
| # then "pindent -r" on a valid Python program produces a program that |
| # is semantically identical to the input (though its indentation may |
| # be different). Running "pindent -e" on that output produces a |
| # program that only differs from the original in indentation. |
| |
| # Other options: |
| # -s stepsize: set the indentation step size (default 8) |
| # -t tabsize : set the number of spaces a tab character is worth (default 8) |
| # -e : expand TABs into spaces |
| # file ... : input file(s) (default standard input) |
| # The results always go to standard output |
| |
| # Caveats: |
| # - comments ending in a backslash will be mistaken for continued lines |
| # - continuations using backslash are always left unchanged |
| # - continuations inside parentheses are not extra indented by -r |
| # but must be indented for -c to work correctly (this breaks |
| # idempotency!) |
| # - continued lines inside triple-quoted strings are totally garbled |
| |
| # Secret feature: |
| # - On input, a block may also be closed with an "end statement" -- |
| # this is a block-closing comment without the '#' sign. |
| |
| # Possible improvements: |
| # - check syntax based on transitions in 'next' table |
| # - better error reporting |
| # - better error recovery |
| # - check identifier after class/def |
| |
| # The following wishes need a more complete tokenization of the source: |
| # - Don't get fooled by comments ending in backslash |
| # - reindent continuation lines indicated by backslash |
| # - handle continuation lines inside parentheses/braces/brackets |
| # - handle triple quoted strings spanning lines |
| # - realign comments |
| # - optionally do much more thorough reformatting, a la C indent |
| |
| # Defaults |
| STEPSIZE = 8 |
| TABSIZE = 8 |
| EXPANDTABS = False |
| |
| import io |
| import re |
| import sys |
| |
| next = {} |
| next['if'] = next['elif'] = 'elif', 'else', 'end' |
| next['while'] = next['for'] = 'else', 'end' |
| next['try'] = 'except', 'finally' |
| next['except'] = 'except', 'else', 'finally', 'end' |
| next['else'] = next['finally'] = next['with'] = \ |
| next['def'] = next['class'] = 'end' |
| next['end'] = () |
| start = 'if', 'while', 'for', 'try', 'with', 'def', 'class' |
| |
| class PythonIndenter: |
| |
| def __init__(self, fpi = sys.stdin, fpo = sys.stdout, |
| indentsize = STEPSIZE, tabsize = TABSIZE, expandtabs = EXPANDTABS): |
| self.fpi = fpi |
| self.fpo = fpo |
| self.indentsize = indentsize |
| self.tabsize = tabsize |
| self.lineno = 0 |
| self.expandtabs = expandtabs |
| self._write = fpo.write |
| self.kwprog = re.compile( |
| r'^(?:\s|\\\n)*(?P<kw>[a-z]+)' |
| r'((?:\s|\\\n)+(?P<id>[a-zA-Z_]\w*))?' |
| r'[^\w]') |
| self.endprog = re.compile( |
| r'^(?:\s|\\\n)*#?\s*end\s+(?P<kw>[a-z]+)' |
| r'(\s+(?P<id>[a-zA-Z_]\w*))?' |
| r'[^\w]') |
| self.wsprog = re.compile(r'^[ \t]*') |
| # end def __init__ |
| |
| def write(self, line): |
| if self.expandtabs: |
| self._write(line.expandtabs(self.tabsize)) |
| else: |
| self._write(line) |
| # end if |
| # end def write |
| |
| def readline(self): |
| line = self.fpi.readline() |
| if line: self.lineno += 1 |
| # end if |
| return line |
| # end def readline |
| |
| def error(self, fmt, *args): |
| if args: fmt = fmt % args |
| # end if |
| sys.stderr.write('Error at line %d: %s\n' % (self.lineno, fmt)) |
| self.write('### %s ###\n' % fmt) |
| # end def error |
| |
| def getline(self): |
| line = self.readline() |
| while line[-2:] == '\\\n': |
| line2 = self.readline() |
| if not line2: break |
| # end if |
| line += line2 |
| # end while |
| return line |
| # end def getline |
| |
| def putline(self, line, indent): |
| tabs, spaces = divmod(indent*self.indentsize, self.tabsize) |
| i = self.wsprog.match(line).end() |
| line = line[i:] |
| if line[:1] not in ('\n', '\r', ''): |
| line = '\t'*tabs + ' '*spaces + line |
| # end if |
| self.write(line) |
| # end def putline |
| |
| def reformat(self): |
| stack = [] |
| while True: |
| line = self.getline() |
| if not line: break # EOF |
| # end if |
| m = self.endprog.match(line) |
| if m: |
| kw = 'end' |
| kw2 = m.group('kw') |
| if not stack: |
| self.error('unexpected end') |
| elif stack.pop()[0] != kw2: |
| self.error('unmatched end') |
| # end if |
| self.putline(line, len(stack)) |
| continue |
| # end if |
| m = self.kwprog.match(line) |
| if m: |
| kw = m.group('kw') |
| if kw in start: |
| self.putline(line, len(stack)) |
| stack.append((kw, kw)) |
| continue |
| # end if |
| if kw in next and stack: |
| self.putline(line, len(stack)-1) |
| kwa, kwb = stack[-1] |
| stack[-1] = kwa, kw |
| continue |
| # end if |
| # end if |
| self.putline(line, len(stack)) |
| # end while |
| if stack: |
| self.error('unterminated keywords') |
| for kwa, kwb in stack: |
| self.write('\t%s\n' % kwa) |
| # end for |
| # end if |
| # end def reformat |
| |
| def delete(self): |
| begin_counter = 0 |
| end_counter = 0 |
| while True: |
| line = self.getline() |
| if not line: break # EOF |
| # end if |
| m = self.endprog.match(line) |
| if m: |
| end_counter += 1 |
| continue |
| # end if |
| m = self.kwprog.match(line) |
| if m: |
| kw = m.group('kw') |
| if kw in start: |
| begin_counter += 1 |
| # end if |
| # end if |
| self.write(line) |
| # end while |
| if begin_counter - end_counter < 0: |
| sys.stderr.write('Warning: input contained more end tags than expected\n') |
| elif begin_counter - end_counter > 0: |
| sys.stderr.write('Warning: input contained less end tags than expected\n') |
| # end if |
| # end def delete |
| |
| def complete(self): |
| stack = [] |
| todo = [] |
| currentws = thisid = firstkw = lastkw = topid = '' |
| while True: |
| line = self.getline() |
| i = self.wsprog.match(line).end() |
| m = self.endprog.match(line) |
| if m: |
| thiskw = 'end' |
| endkw = m.group('kw') |
| thisid = m.group('id') |
| else: |
| m = self.kwprog.match(line) |
| if m: |
| thiskw = m.group('kw') |
| if thiskw not in next: |
| thiskw = '' |
| # end if |
| if thiskw in ('def', 'class'): |
| thisid = m.group('id') |
| else: |
| thisid = '' |
| # end if |
| elif line[i:i+1] in ('\n', '#'): |
| todo.append(line) |
| continue |
| else: |
| thiskw = '' |
| # end if |
| # end if |
| indentws = line[:i] |
| indent = len(indentws.expandtabs(self.tabsize)) |
| current = len(currentws.expandtabs(self.tabsize)) |
| while indent < current: |
| if firstkw: |
| if topid: |
| s = '# end %s %s\n' % ( |
| firstkw, topid) |
| else: |
| s = '# end %s\n' % firstkw |
| # end if |
| self.write(currentws + s) |
| firstkw = lastkw = '' |
| # end if |
| currentws, firstkw, lastkw, topid = stack.pop() |
| current = len(currentws.expandtabs(self.tabsize)) |
| # end while |
| if indent == current and firstkw: |
| if thiskw == 'end': |
| if endkw != firstkw: |
| self.error('mismatched end') |
| # end if |
| firstkw = lastkw = '' |
| elif not thiskw or thiskw in start: |
| if topid: |
| s = '# end %s %s\n' % ( |
| firstkw, topid) |
| else: |
| s = '# end %s\n' % firstkw |
| # end if |
| self.write(currentws + s) |
| firstkw = lastkw = topid = '' |
| # end if |
| # end if |
| if indent > current: |
| stack.append((currentws, firstkw, lastkw, topid)) |
| if thiskw and thiskw not in start: |
| # error |
| thiskw = '' |
| # end if |
| currentws, firstkw, lastkw, topid = \ |
| indentws, thiskw, thiskw, thisid |
| # end if |
| if thiskw: |
| if thiskw in start: |
| firstkw = lastkw = thiskw |
| topid = thisid |
| else: |
| lastkw = thiskw |
| # end if |
| # end if |
| for l in todo: self.write(l) |
| # end for |
| todo = [] |
| if not line: break |
| # end if |
| self.write(line) |
| # end while |
| # end def complete |
| # end class PythonIndenter |
| |
| # Simplified user interface |
| # - xxx_filter(input, output): read and write file objects |
| # - xxx_string(s): take and return string object |
| # - xxx_file(filename): process file in place, return true iff changed |
| |
| def complete_filter(input = sys.stdin, output = sys.stdout, |
| stepsize = STEPSIZE, tabsize = TABSIZE, expandtabs = EXPANDTABS): |
| pi = PythonIndenter(input, output, stepsize, tabsize, expandtabs) |
| pi.complete() |
| # end def complete_filter |
| |
| def delete_filter(input= sys.stdin, output = sys.stdout, |
| stepsize = STEPSIZE, tabsize = TABSIZE, expandtabs = EXPANDTABS): |
| pi = PythonIndenter(input, output, stepsize, tabsize, expandtabs) |
| pi.delete() |
| # end def delete_filter |
| |
| def reformat_filter(input = sys.stdin, output = sys.stdout, |
| stepsize = STEPSIZE, tabsize = TABSIZE, expandtabs = EXPANDTABS): |
| pi = PythonIndenter(input, output, stepsize, tabsize, expandtabs) |
| pi.reformat() |
| # end def reformat_filter |
| |
| def complete_string(source, stepsize = STEPSIZE, tabsize = TABSIZE, expandtabs = EXPANDTABS): |
| input = io.StringIO(source) |
| output = io.StringIO() |
| pi = PythonIndenter(input, output, stepsize, tabsize, expandtabs) |
| pi.complete() |
| return output.getvalue() |
| # end def complete_string |
| |
| def delete_string(source, stepsize = STEPSIZE, tabsize = TABSIZE, expandtabs = EXPANDTABS): |
| input = io.StringIO(source) |
| output = io.StringIO() |
| pi = PythonIndenter(input, output, stepsize, tabsize, expandtabs) |
| pi.delete() |
| return output.getvalue() |
| # end def delete_string |
| |
| def reformat_string(source, stepsize = STEPSIZE, tabsize = TABSIZE, expandtabs = EXPANDTABS): |
| input = io.StringIO(source) |
| output = io.StringIO() |
| pi = PythonIndenter(input, output, stepsize, tabsize, expandtabs) |
| pi.reformat() |
| return output.getvalue() |
| # end def reformat_string |
| |
| def make_backup(filename): |
| import os, os.path |
| backup = filename + '~' |
| if os.path.lexists(backup): |
| try: |
| os.remove(backup) |
| except OSError: |
| print("Can't remove backup %r" % (backup,), file=sys.stderr) |
| # end try |
| # end if |
| try: |
| os.rename(filename, backup) |
| except OSError: |
| print("Can't rename %r to %r" % (filename, backup), file=sys.stderr) |
| # end try |
| # end def make_backup |
| |
| def complete_file(filename, stepsize = STEPSIZE, tabsize = TABSIZE, expandtabs = EXPANDTABS): |
| with open(filename, 'r') as f: |
| source = f.read() |
| # end with |
| result = complete_string(source, stepsize, tabsize, expandtabs) |
| if source == result: return 0 |
| # end if |
| make_backup(filename) |
| with open(filename, 'w') as f: |
| f.write(result) |
| # end with |
| return 1 |
| # end def complete_file |
| |
| def delete_file(filename, stepsize = STEPSIZE, tabsize = TABSIZE, expandtabs = EXPANDTABS): |
| with open(filename, 'r') as f: |
| source = f.read() |
| # end with |
| result = delete_string(source, stepsize, tabsize, expandtabs) |
| if source == result: return 0 |
| # end if |
| make_backup(filename) |
| with open(filename, 'w') as f: |
| f.write(result) |
| # end with |
| return 1 |
| # end def delete_file |
| |
| def reformat_file(filename, stepsize = STEPSIZE, tabsize = TABSIZE, expandtabs = EXPANDTABS): |
| with open(filename, 'r') as f: |
| source = f.read() |
| # end with |
| result = reformat_string(source, stepsize, tabsize, expandtabs) |
| if source == result: return 0 |
| # end if |
| make_backup(filename) |
| with open(filename, 'w') as f: |
| f.write(result) |
| # end with |
| return 1 |
| # end def reformat_file |
| |
| # Test program when called as a script |
| |
| usage = """ |
| usage: pindent (-c|-d|-r) [-s stepsize] [-t tabsize] [-e] [file] ... |
| -c : complete a correctly indented program (add #end directives) |
| -d : delete #end directives |
| -r : reformat a completed program (use #end directives) |
| -s stepsize: indentation step (default %(STEPSIZE)d) |
| -t tabsize : the worth in spaces of a tab (default %(TABSIZE)d) |
| -e : expand TABs into spaces (default OFF) |
| [file] ... : files are changed in place, with backups in file~ |
| If no files are specified or a single - is given, |
| the program acts as a filter (reads stdin, writes stdout). |
| """ % vars() |
| |
| def error_both(op1, op2): |
| sys.stderr.write('Error: You can not specify both '+op1+' and -'+op2[0]+' at the same time\n') |
| sys.stderr.write(usage) |
| sys.exit(2) |
| # end def error_both |
| |
| def test(): |
| import getopt |
| try: |
| opts, args = getopt.getopt(sys.argv[1:], 'cdrs:t:e') |
| except getopt.error as msg: |
| sys.stderr.write('Error: %s\n' % msg) |
| sys.stderr.write(usage) |
| sys.exit(2) |
| # end try |
| action = None |
| stepsize = STEPSIZE |
| tabsize = TABSIZE |
| expandtabs = EXPANDTABS |
| for o, a in opts: |
| if o == '-c': |
| if action: error_both(o, action) |
| # end if |
| action = 'complete' |
| elif o == '-d': |
| if action: error_both(o, action) |
| # end if |
| action = 'delete' |
| elif o == '-r': |
| if action: error_both(o, action) |
| # end if |
| action = 'reformat' |
| elif o == '-s': |
| stepsize = int(a) |
| elif o == '-t': |
| tabsize = int(a) |
| elif o == '-e': |
| expandtabs = True |
| # end if |
| # end for |
| if not action: |
| sys.stderr.write( |
| 'You must specify -c(omplete), -d(elete) or -r(eformat)\n') |
| sys.stderr.write(usage) |
| sys.exit(2) |
| # end if |
| if not args or args == ['-']: |
| action = eval(action + '_filter') |
| action(sys.stdin, sys.stdout, stepsize, tabsize, expandtabs) |
| else: |
| action = eval(action + '_file') |
| for filename in args: |
| action(filename, stepsize, tabsize, expandtabs) |
| # end for |
| # end if |
| # end def test |
| |
| if __name__ == '__main__': |
| test() |
| # end if |