ref: 3a41ce3bf314caad67c2c52a06142f7ac60611c7
dir: /sys/src/cmd/python/Demo/parser/unparse.py/
"Usage: unparse.py <path to source file>"
import sys
import _ast
import cStringIO
import os
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 ")
first = True
for a in t.names:
if first:
first = False
else:
self.write(", ")
self.write(a.name)
if a.asname:
self.write(" as "+a.asname)
def _ImportFrom(self, t):
self.fill("from ")
self.write(t.module)
self.write(" import ")
for i, a in enumerate(t.names):
if i == 0:
self.write(", ")
self.write(a.name)
if a.asname:
self.write(" as "+a.asname)
# 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.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")
for i, n in enumerate(t.names):
if i != 0:
self.write(",")
self.write(" " + n)
def _Yield(self, t):
self.fill("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.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.decorators:
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("[")
for e in t.elts:
self.dispatch(e)
self.write(", ")
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.dispatch(t.body)
self.write(" if ")
self.dispatch(t.test)
if t.orelse:
self.write(" else ")
self.dispatch(t.orelse)
def _Dict(self, t):
self.write("{")
for k,v in zip(t.keys, t.values):
self.dispatch(k)
self.write(" : ")
self.dispatch(v)
self.write(", ")
self.write("}")
def _Tuple(self, t):
if not t.elts:
self.write("()")
return
self.write("(")
for e in t.elts:
self.dispatch(e)
self.write(", ")
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("(")
self.dispatch(t.values[0])
for v in t.values[1:]:
self.write(" %s " % self.boolops[t.op.__class__])
self.dispatch(v)
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):
for i, d in enumerate(t.dims):
if i != 0:
self.write(': ')
self.dispatch(d)
# 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 roundtrip(filename, output=sys.stdout):
source = open(filename).read()
tree = compile(source, filename, "exec", 0x400)
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:])