/Demo/parser/unparse.py
http://unladen-swallow.googlecode.com/ · Python · 518 lines · 429 code · 70 blank · 19 comment · 81 complexity · 1931bab04f70736294ae846c3265878c MD5 · raw file
- "Usage: unparse.py <path to source file>"
- import sys
- import _ast
- import cStringIO
- import os
- def interleave(inter, f, seq):
- """Call f on each item in seq, calling inter() in between.
- """
- seq = iter(seq)
- try:
- f(seq.next())
- except StopIteration:
- pass
- else:
- for x in seq:
- inter()
- f(x)
- class Unparser:
- """Methods in this class recursively traverse an AST and
- output source code for the abstract syntax; original formatting
- is disregarged. """
- def __init__(self, tree, file = sys.stdout):
- """Unparser(tree, file=sys.stdout) -> None.
- Print the source for tree to file."""
- self.f = file
- self._indent = 0
- self.dispatch(tree)
- print >>self.f,""
- self.f.flush()
- def fill(self, text = ""):
- "Indent a piece of text, according to the current indentation level"
- self.f.write("\n"+" "*self._indent + text)
- def write(self, text):
- "Append a piece of text to the current line."
- self.f.write(text)
- def enter(self):
- "Print ':', and increase the indentation."
- self.write(":")
- self._indent += 1
- def leave(self):
- "Decrease the indentation level."
- self._indent -= 1
- def dispatch(self, tree):
- "Dispatcher function, dispatching tree type T to method _T."
- if isinstance(tree, list):
- for t in tree:
- self.dispatch(t)
- return
- meth = getattr(self, "_"+tree.__class__.__name__)
- meth(tree)
- ############### Unparsing methods ######################
- # There should be one method per concrete grammar type #
- # Constructors should be grouped by sum type. Ideally, #
- # this would follow the order in the grammar, but #
- # currently doesn't. #
- ########################################################
- def _Module(self, tree):
- for stmt in tree.body:
- self.dispatch(stmt)
- # stmt
- def _Expr(self, tree):
- self.fill()
- self.dispatch(tree.value)
- def _Import(self, t):
- self.fill("import ")
- interleave(lambda: self.write(", "), self.dispatch, t.names)
- def _ImportFrom(self, t):
- self.fill("from ")
- self.write(t.module)
- self.write(" import ")
- interleave(lambda: self.write(", "), self.dispatch, t.names)
- # XXX(jpe) what is level for?
- def _Assign(self, t):
- self.fill()
- for target in t.targets:
- self.dispatch(target)
- self.write(" = ")
- self.dispatch(t.value)
- def _AugAssign(self, t):
- self.fill()
- self.dispatch(t.target)
- self.write(" "+self.binop[t.op.__class__.__name__]+"= ")
- self.dispatch(t.value)
- def _Return(self, t):
- self.fill("return")
- if t.value:
- self.write(" ")
- self.dispatch(t.value)
- def _Pass(self, t):
- self.fill("pass")
- def _Break(self, t):
- self.fill("break")
- def _Continue(self, t):
- self.fill("continue")
- def _Delete(self, t):
- self.fill("del ")
- self.dispatch(t.targets)
- def _Assert(self, t):
- self.fill("assert ")
- self.dispatch(t.test)
- if t.msg:
- self.write(", ")
- self.dispatch(t.msg)
- def _Exec(self, t):
- self.fill("exec ")
- self.dispatch(t.body)
- if t.globals:
- self.write(" in ")
- self.dispatch(t.globals)
- if t.locals:
- self.write(", ")
- self.dispatch(t.locals)
- def _Print(self, t):
- self.fill("print ")
- do_comma = False
- if t.dest:
- self.write(">>")
- self.dispatch(t.dest)
- do_comma = True
- for e in t.values:
- if do_comma:self.write(", ")
- else:do_comma=True
- self.dispatch(e)
- if not t.nl:
- self.write(",")
- def _Global(self, t):
- self.fill("global ")
- interleave(lambda: self.write(", "), self.write, t.names)
- def _Yield(self, t):
- self.write("(")
- self.write("yield")
- if t.value:
- self.write(" ")
- self.dispatch(t.value)
- self.write(")")
- def _Raise(self, t):
- self.fill('raise ')
- if t.type:
- self.dispatch(t.type)
- if t.inst:
- self.write(", ")
- self.dispatch(t.inst)
- if t.tback:
- self.write(", ")
- self.dispatch(t.tback)
- def _TryExcept(self, t):
- self.fill("try")
- self.enter()
- self.dispatch(t.body)
- self.leave()
- for ex in t.handlers:
- self.dispatch(ex)
- if t.orelse:
- self.fill("else")
- self.enter()
- self.dispatch(t.orelse)
- self.leave()
- def _TryFinally(self, t):
- self.fill("try")
- self.enter()
- self.dispatch(t.body)
- self.leave()
- self.fill("finally")
- self.enter()
- self.dispatch(t.finalbody)
- self.leave()
- def _ExceptHandler(self, t):
- self.fill("except")
- if t.type:
- self.write(" ")
- self.dispatch(t.type)
- if t.name:
- self.write(", ")
- self.dispatch(t.name)
- self.enter()
- self.dispatch(t.body)
- self.leave()
- def _ClassDef(self, t):
- self.write("\n")
- self.fill("class "+t.name)
- if t.bases:
- self.write("(")
- for a in t.bases:
- self.dispatch(a)
- self.write(", ")
- self.write(")")
- self.enter()
- self.dispatch(t.body)
- self.leave()
- def _FunctionDef(self, t):
- self.write("\n")
- for deco in t.decorator_list:
- self.fill("@")
- self.dispatch(deco)
- self.fill("def "+t.name + "(")
- self.dispatch(t.args)
- self.write(")")
- self.enter()
- self.dispatch(t.body)
- self.leave()
- def _For(self, t):
- self.fill("for ")
- self.dispatch(t.target)
- self.write(" in ")
- self.dispatch(t.iter)
- self.enter()
- self.dispatch(t.body)
- self.leave()
- if t.orelse:
- self.fill("else")
- self.enter()
- self.dispatch(t.orelse)
- self.leave
- def _If(self, t):
- self.fill("if ")
- self.dispatch(t.test)
- self.enter()
- # XXX elif?
- self.dispatch(t.body)
- self.leave()
- if t.orelse:
- self.fill("else")
- self.enter()
- self.dispatch(t.orelse)
- self.leave()
- def _While(self, t):
- self.fill("while ")
- self.dispatch(t.test)
- self.enter()
- self.dispatch(t.body)
- self.leave()
- if t.orelse:
- self.fill("else")
- self.enter()
- self.dispatch(t.orelse)
- self.leave
- def _With(self, t):
- self.fill("with ")
- self.dispatch(t.context_expr)
- if t.optional_vars:
- self.write(" as ")
- self.dispatch(t.optional_vars)
- self.enter()
- self.dispatch(t.body)
- self.leave()
- # expr
- def _Str(self, tree):
- self.write(repr(tree.s))
- def _Name(self, t):
- self.write(t.id)
- def _Repr(self, t):
- self.write("`")
- self.dispatch(t.value)
- self.write("`")
- def _Num(self, t):
- self.write(repr(t.n))
- def _List(self, t):
- self.write("[")
- interleave(lambda: self.write(", "), self.dispatch, t.elts)
- self.write("]")
- def _ListComp(self, t):
- self.write("[")
- self.dispatch(t.elt)
- for gen in t.generators:
- self.dispatch(gen)
- self.write("]")
- def _GeneratorExp(self, t):
- self.write("(")
- self.dispatch(t.elt)
- for gen in t.generators:
- self.dispatch(gen)
- self.write(")")
- def _comprehension(self, t):
- self.write(" for ")
- self.dispatch(t.target)
- self.write(" in ")
- self.dispatch(t.iter)
- for if_clause in t.ifs:
- self.write(" if ")
- self.dispatch(if_clause)
- def _IfExp(self, t):
- self.write("(")
- self.dispatch(t.body)
- self.write(" if ")
- self.dispatch(t.test)
- self.write(" else ")
- self.dispatch(t.orelse)
- self.write(")")
- def _Dict(self, t):
- self.write("{")
- def writem((k, v)):
- self.dispatch(k)
- self.write(": ")
- self.dispatch(v)
- interleave(lambda: self.write(", "), writem, zip(t.keys, t.values))
- self.write("}")
- def _Tuple(self, t):
- self.write("(")
- if len(t.elts) == 1:
- (elt,) = t.elts
- self.dispatch(elt)
- self.write(",")
- else:
- interleave(lambda: self.write(", "), self.dispatch, t.elts)
- self.write(")")
- unop = {"Invert":"~", "Not": "not", "UAdd":"+", "USub":"-"}
- def _UnaryOp(self, t):
- self.write(self.unop[t.op.__class__.__name__])
- self.write("(")
- self.dispatch(t.operand)
- self.write(")")
- binop = { "Add":"+", "Sub":"-", "Mult":"*", "Div":"/", "Mod":"%",
- "LShift":">>", "RShift":"<<", "BitOr":"|", "BitXor":"^", "BitAnd":"&",
- "FloorDiv":"//", "Pow": "**"}
- def _BinOp(self, t):
- self.write("(")
- self.dispatch(t.left)
- self.write(" " + self.binop[t.op.__class__.__name__] + " ")
- self.dispatch(t.right)
- self.write(")")
- cmpops = {"Eq":"==", "NotEq":"!=", "Lt":"<", "LtE":"<=", "Gt":">", "GtE":">=",
- "Is":"is", "IsNot":"is not", "In":"in", "NotIn":"not in"}
- def _Compare(self, t):
- self.write("(")
- self.dispatch(t.left)
- for o, e in zip(t.ops, t.comparators):
- self.write(" " + self.cmpops[o.__class__.__name__] + " ")
- self.dispatch(e)
- self.write(")")
- boolops = {_ast.And: 'and', _ast.Or: 'or'}
- def _BoolOp(self, t):
- self.write("(")
- s = " %s " % self.boolops[t.op.__class__]
- interleave(lambda: self.write(s), self.dispatch, t.values)
- self.write(")")
- def _Attribute(self,t):
- self.dispatch(t.value)
- self.write(".")
- self.write(t.attr)
- def _Call(self, t):
- self.dispatch(t.func)
- self.write("(")
- comma = False
- for e in t.args:
- if comma: self.write(", ")
- else: comma = True
- self.dispatch(e)
- for e in t.keywords:
- if comma: self.write(", ")
- else: comma = True
- self.dispatch(e)
- if t.starargs:
- if comma: self.write(", ")
- else: comma = True
- self.write("*")
- self.dispatch(t.starargs)
- if t.kwargs:
- if comma: self.write(", ")
- else: comma = True
- self.write("**")
- self.dispatch(t.kwargs)
- self.write(")")
- def _Subscript(self, t):
- self.dispatch(t.value)
- self.write("[")
- self.dispatch(t.slice)
- self.write("]")
- # slice
- def _Ellipsis(self, t):
- self.write("...")
- def _Index(self, t):
- self.dispatch(t.value)
- def _Slice(self, t):
- if t.lower:
- self.dispatch(t.lower)
- self.write(":")
- if t.upper:
- self.dispatch(t.upper)
- if t.step:
- self.write(":")
- self.dispatch(t.step)
- def _ExtSlice(self, t):
- interleave(lambda: self.write(', '), self.dispatch, t.dims)
- # others
- def _arguments(self, t):
- first = True
- nonDef = len(t.args)-len(t.defaults)
- for a in t.args[0:nonDef]:
- if first:first = False
- else: self.write(", ")
- self.dispatch(a)
- for a,d in zip(t.args[nonDef:], t.defaults):
- if first:first = False
- else: self.write(", ")
- self.dispatch(a),
- self.write("=")
- self.dispatch(d)
- if t.vararg:
- if first:first = False
- else: self.write(", ")
- self.write("*"+t.vararg)
- if t.kwarg:
- if first:first = False
- else: self.write(", ")
- self.write("**"+t.kwarg)
- def _keyword(self, t):
- self.write(t.arg)
- self.write("=")
- self.dispatch(t.value)
- def _Lambda(self, t):
- self.write("lambda ")
- self.dispatch(t.args)
- self.write(": ")
- self.dispatch(t.body)
- def _alias(self, t):
- self.write(t.name)
- if t.asname:
- self.write(" as "+t.asname)
- def roundtrip(filename, output=sys.stdout):
- source = open(filename).read()
- tree = compile(source, filename, "exec", _ast.PyCF_ONLY_AST)
- Unparser(tree, output)
- def testdir(a):
- try:
- names = [n for n in os.listdir(a) if n.endswith('.py')]
- except OSError:
- print >> sys.stderr, "Directory not readable: %s" % a
- else:
- for n in names:
- fullname = os.path.join(a, n)
- if os.path.isfile(fullname):
- output = cStringIO.StringIO()
- print 'Testing %s' % fullname
- try:
- roundtrip(fullname, output)
- except Exception, e:
- print ' Failed to compile, exception is %s' % repr(e)
- elif os.path.isdir(fullname):
- testdir(fullname)
- def main(args):
- if args[0] == '--testdir':
- for a in args[1:]:
- testdir(a)
- else:
- for a in args:
- roundtrip(a)
- if __name__=='__main__':
- main(sys.argv[1:])