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pindent.py
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#! /usr/bin/env python3 | |
# Via: https://github.com/python/cpython/blob/main/Tools/scripts/pindent.py | |
# See also: https://stackoverflow.com/a/118744/454773 | |
# 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 |
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