[Python-checkins] r54441 - python/trunk/Demo/parser/unparse.py

Mon Mar 19 20:02:52 CET 2007

Author: georg.brandl
Date: Mon Mar 19 20:02:48 2007
New Revision: 54441
Modified:
 python/trunk/Demo/parser/unparse.py
Log:
Patch #1683328: fixes and enhancements for "unparse" demo.
Modified: python/trunk/Demo/parser/unparse.py
==============================================================================

--- python/trunk/Demo/parser/unparse.py	(original)
+++ python/trunk/Demo/parser/unparse.py	Mon Mar 19 20:02:48 2007
@@ -4,6 +4,19 @@
 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
@@ -63,26 +76,13 @@
 
 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)
+ interleave(lambda: self.write(", "), self.dispatch, t.names)
 
 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)
+ interleave(lambda: self.write(", "), self.dispatch, t.names)
 # XXX(jpe) what is level for?
 
 def _Assign(self, t):
@@ -99,8 +99,9 @@
 self.dispatch(t.value)
 
 def _Return(self, t):
- self.fill("return ")
+ self.fill("return")
 if t.value:
+ self.write(" ")
 self.dispatch(t.value)
 
 def _Pass(self, t):
@@ -148,18 +149,16 @@
 self.write(",")
 
 def _Global(self, t):
- self.fill("global")
- for i, n in enumerate(t.names):
- if i != 0:
- self.write(",")
- self.write(" " + n)
+ self.fill("global ")
+ interleave(lambda: self.write(", "), self.write, t.names)
 
 def _Yield(self, t):
- self.fill("yield")
+ self.write("(")
+ self.write("yield")
 if t.value:
- self.write(" (")
+ self.write(" ")
 self.dispatch(t.value)
- self.write(")")
+ self.write(")")
 
 def _Raise(self, t):
 self.fill('raise ')
@@ -198,8 +197,9 @@
 self.leave()
 
 def _excepthandler(self, t):
- self.fill("except ")
+ self.fill("except")
 if t.type:
+ self.write(" ")
 self.dispatch(t.type)
 if t.name:
 self.write(", ")
@@ -299,9 +299,7 @@
 
 def _List(self, t):
 self.write("[")
- for e in t.elts:
- self.dispatch(e)
- self.write(", ")
+ interleave(lambda: self.write(", "), self.dispatch, t.elts)
 self.write("]")
 
 def _ListComp(self, t):
@@ -328,30 +326,31 @@
 self.dispatch(if_clause)
 
 def _IfExp(self, t):
+ self.write("(")
 self.dispatch(t.body)
 self.write(" if ")
 self.dispatch(t.test)
- if t.orelse:
- self.write(" else ")
- self.dispatch(t.orelse)
+ self.write(" else ")
+ self.dispatch(t.orelse)
+ self.write(")")
 
 def _Dict(self, t):
 self.write("{")
- for k,v in zip(t.keys, t.values):
+ def writem((k, v)):
 self.dispatch(k)
- self.write(" : ")
+ self.write(": ")
 self.dispatch(v)
- self.write(", ")
+ interleave(lambda: self.write(", "), writem, zip(t.keys, t.values))
 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(", ")
+ 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":"-"}
@@ -367,7 +366,7 @@
 def _BinOp(self, t):
 self.write("(")
 self.dispatch(t.left)
- self.write(")" + self.binop[t.op.__class__.__name__] + "(")
+ self.write(" " + self.binop[t.op.__class__.__name__] + " ")
 self.dispatch(t.right)
 self.write(")")
 
@@ -377,17 +376,15 @@
 self.write("(")
 self.dispatch(t.left)
 for o, e in zip(t.ops, t.comparators):
- self.write(") " +self.cmpops[o.__class__.__name__] + " (")
+ 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)
+ s = " %s " % self.boolops[t.op.__class__]
+ interleave(lambda: self.write(s), self.dispatch, t.values)
 self.write(")")
 
 def _Attribute(self,t):
@@ -443,10 +440,7 @@
 self.dispatch(t.step)
 
 def _ExtSlice(self, t):
- for i, d in enumerate(t.dims):
- if i != 0:
- self.write(': ')
- self.dispatch(d)
+ interleave(lambda: self.write(', '), self.dispatch, t.dims)
 
 # others
 def _arguments(self, t):
@@ -482,9 +476,14 @@
 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", 0x400)
+ tree = compile(source, filename, "exec", _ast.PyCF_ONLY_AST)
 Unparser(tree, output)
 
 
