ref: 6b1d0a8102b9740990d3defca228dc2c7b9102d2
dir: /man/simplecpp/
#!/usr/bin/env python # # Copyright (c) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008 # Contributors to the Freedoom project. All rights reserved. # # Redistribution and use in source and binary forms, with or without # modification, are permitted provided that the following conditions are # met: # # * Redistributions of source code must retain the above copyright # notice, this list of conditions and the following disclaimer. # * Redistributions in binary form must reproduce the above copyright # notice, this list of conditions and the following disclaimer in the # documentation and/or other materials provided with the distribution. # * Neither the name of the freedoom project nor the names of its # contributors may be used to endorse or promote products derived from # this software without specific prior written permission. # # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS # IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED # TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A # PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER # OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, # EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, # PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR # PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF # LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING # NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS # SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. # # # simple cpp-style preprocessor # # Understands most features of the C preprocessor, including: # #if .. #elif .. #else .. #endif # - with expressions # #ifdef # #define # #include # import collections import io import sys import re debug = False defines = collections.defaultdict(lambda: False) command_re = re.compile(r"\#(\w+)(\s+(.*))?") include_re = re.compile(r"\s*\"(.*)\"\s*") define_re = re.compile(r"\s*(\S+)\s*(.*?)\s*$") def debug_msg(message): if debug: sys.stderr.write(message) # Parse command line options def parse_cmdline(): for arg in sys.argv[1:]: if not arg.startswith("-D"): continue name = arg[2:] if '=' in name: name, value = name.split('=', 1) else: value = True defines[name] = value def parse_stream(stream): result = read_block(stream, False) if result is not None: raise Exception("Mismatched #if in '%s'" % stream.name) def parse_file(filename): f = io.open(filename, encoding='UTF-8') try: parse_stream(f) finally: f.close() # Evaluate an expression using Python's eval() function. def eval_expr(expr): expr = expr.replace("||", " or ") \ .replace("&&", " and ") \ .replace("!", "not ") code = compile(expr, "", "eval") result = eval(code, {}, defines) return result # #include def cmd_include(arg): # Extract the filename match = include_re.match(arg) if not match: raise Exception("Invalid 'include' command") filename = match.group(1) # Open the file and process it parse_file(filename) # #define def cmd_define(arg): match = define_re.match(arg) name = match.group(1) value = match.group(2) if value == '': value = True defines[name] = value # #undef def cmd_undef(arg): if arg in defines: del defines[arg] # #ifdef/#ifndef def cmd_ifdef(arg, command, stream, ignore): # Get the define name debug_msg("%s %s >\n" % (command, arg)) # Should we ignore the contents of this block? sub_ignore = not eval_expr(arg) if "n" in command: sub_ignore = not sub_ignore # Parse the block result, newarg = read_block(stream, ignore or sub_ignore) debug_msg("%s %s < (%s)\n" % (command, arg, result)) # There may be a second "else" block to parse: if result == "else": debug_msg("%s %s else >\n" % (command, arg)) result, arg = read_block(stream, ignore or (not sub_ignore)) debug_msg("%s %s else < (%s)\n" % (command, arg, result)) if result == "elif": debug_msg("%s %s elif %s>\n" % (command, arg, newarg)) cmd_ifdef(newarg, "if", stream, ignore or (not sub_ignore)) result = "endif" # Should end in an endif: if result != "endif": raise Exception("'if' block did not end in an 'endif'") commands = { "include" : cmd_include, "define" : cmd_define, "undef" : cmd_undef, "if" : cmd_ifdef, "ifdef" : cmd_ifdef, "ifn" : cmd_ifdef, "ifndef" : cmd_ifdef, } # Recursive block reading function # if 'ignore' argument is 1, contents are ignored def read_block(stream, ignore): for line in stream: # Remove newline line = line[0:-1] # Check if this line has a command match = command_re.match(line) if match: command = match.group(1) arg = match.group(3) if command in ("else", "elif", "endif"): return (command, arg) elif command not in commands: raise Exception("Unknown command: '%s'" % \ command) # Get the callback function. func = commands[command] # Invoke the callback function. #ifdef commands # are a special case and need extra arguments. # Other commands are only executed if we are not # ignoring this block. if func == cmd_ifdef: cmd_ifdef(arg, command=command, stream=stream, ignore=ignore) elif not ignore: func(arg) else: if not ignore: for key, value in defines.items(): if isinstance(value, str): line = line.replace(key, value) print(line) parse_cmdline() parse_stream(sys.stdin)