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pbot/applets/paren/paren.py
Pragmatic Software 3d97dc2c33 Rename "modules" to "applets"
"Applet" is a much better name for the external command-line
scripts and programs that can be loaded as PBot commands. They
will no longer be confused with Perl modules.

https://en.wikipedia.org/wiki/Applet
2021-11-19 18:05:50 -08:00

85 lines
2.6 KiB
Python
Executable File

#!/usr/bin/env python2
from __future__ import print_function
import sys
from pycparser import c_parser, c_generator, c_ast, plyparser
from pycparser.ply import yacc
with open("paren/stddef") as f:
STDDEF = f.read()
class CParser(c_parser.CParser):
def __init__(self, *a, **kw):
super(CParser, self).__init__(*a, **kw)
self.cparser = yacc.yacc(
module=self,
start='expression',
debug=kw.get('yacc_debug', False),
errorlog=yacc.NullLogger(),
optimize=kw.get('yacc_optimize', True),
tabmodule=kw.get('yacctab', 'yacctab'))
def parse(self, text, filename='', debuglevel=0):
self.clex.filename = filename
self.clex.reset_lineno()
self._scope_stack = [dict()]
self._last_yielded_token = None
for name in STDDEF.split('\n'):
if name:
self._add_typedef_name(name, None)
return self.cparser.parse(
input=text,
lexer=self.clex,
debug=debuglevel)
class CGenerator(c_generator.CGenerator):
def _is_simple_node(self, n):
return isinstance(n, (c_ast.Constant, c_ast.ID, c_ast.FuncCall))
def visit_UnaryOp(self, n):
# don't parenthesize an operand to sizeof if it's not a type
if n.op == 'sizeof':
if isinstance(n.expr, c_ast.Typename):
return 'sizeof (%s)' % self.visit(n.expr)
else:
return 'sizeof %s' % self._parenthesize_unless_simple(n.expr)
else:
operand = self.visit(n.expr)
if isinstance(n.expr, c_ast.ArrayRef) or not self._is_simple_node(n.expr):
operand = '(%s)' % operand
if n.op in ('p++', 'p--'):
return operand + n.op[1:]
else:
return n.op + operand
def visit_TernaryOp(self, n):
return '({0}) ? ({1}) : ({2})'.format(
self.visit(n.cond),
self.visit(n.iftrue),
self.visit(n.iffalse))
def visit_Assignment(self, n):
return '%s %s %s' % (self.visit(n.lvalue), n.op, self._parenthesize_unless_simple(n.rvalue))
def parenthesize(source):
parser = CParser(yacc_optimize=False)
try:
ast = parser.parse(source, '<input>')
except plyparser.ParseError as e:
print("Error: " + e.args[0])
return
generator = CGenerator()
print(generator.visit(ast))
if __name__ == "__main__":
if len(sys.argv) > 1:
parenthesize(' '.join(sys.argv[1:]).rstrip(';'))
elif len(sys.argv) == 1:
print("Usage: paren <expression>")
else:
print('error')