import imp import os import marshal import stat import string import struct import sys import types from cStringIO import StringIO from compiler import ast, parse, walk from compiler import pyassem, misc from compiler.pyassem import CO_VARARGS, CO_VARKEYWORDS, CO_NEWLOCALS, TupleArg # Do we have Python 1.x or Python 2.x? try: VERSION = sys.version_info[0] except AttributeError: VERSION = 1 callfunc_opcode_info = { # (Have *args, Have **args) : opcode (0,0) : "CALL_FUNCTION", (1,0) : "CALL_FUNCTION_VAR", (0,1) : "CALL_FUNCTION_KW", (1,1) : "CALL_FUNCTION_VAR_KW", } def compile(filename, display=0): f = open(filename) buf = f.read() f.close() mod = Module(buf, filename) mod.compile(display) f = open(filename + "c", "wb") mod.dump(f) f.close() class Module: def __init__(self, source, filename): self.filename = filename self.source = source self.code = None def compile(self, display=0): ast = parse(self.source) root, filename = os.path.split(self.filename) gen = ModuleCodeGenerator(filename) walk(ast, gen, 1) if display: import pprint print pprint.pprint(ast) self.code = gen.getCode() def dump(self, f): f.write(self.getPycHeader()) marshal.dump(self.code, f) MAGIC = imp.get_magic() def getPycHeader(self): # compile.c uses marshal to write a long directly, with # calling the interface that would also generate a 1-byte code # to indicate the type of the value. simplest way to get the # same effect is to call marshal and then skip the code. mtime = os.stat(self.filename)[stat.ST_MTIME] mtime = struct.pack('i', mtime) return self.MAGIC + mtime class CodeGenerator: optimized = 0 # is namespace access optimized? def __init__(self, filename): ## Subclasses must define a constructor that intializes self.graph ## before calling this init function, e.g. ## self.graph = pyassem.PyFlowGraph() self.filename = filename self.locals = misc.Stack() self.loops = misc.Stack() self.curStack = 0 self.maxStack = 0 self.last_lineno = None self._setupGraphDelegation() def _setupGraphDelegation(self): self.emit = self.graph.emit self.newBlock = self.graph.newBlock self.startBlock = self.graph.startBlock self.nextBlock = self.graph.nextBlock self.setDocstring = self.graph.setDocstring def getCode(self): """Return a code object""" return self.graph.getCode() # Next five methods handle name access def isLocalName(self, name): return self.locals.top().has_elt(name) def storeName(self, name): self._nameOp('STORE', name) def loadName(self, name): self._nameOp('LOAD', name) def delName(self, name): self._nameOp('DELETE', name) def _nameOp(self, prefix, name): if not self.optimized: self.emit(prefix + '_NAME', name) return if self.isLocalName(name): self.emit(prefix + '_FAST', name) else: self.emit(prefix + '_GLOBAL', name) def set_lineno(self, node): """Emit SET_LINENO if node has lineno attribute and it is different than the last lineno emitted. Returns true if SET_LINENO was emitted. There are no rules for when an AST node should have a lineno attribute. The transformer and AST code need to be reviewed and a consistent policy implemented and documented. Until then, this method works around missing line numbers. """ lineno = getattr(node, 'lineno', None) if lineno is not None and lineno != self.last_lineno: self.emit('SET_LINENO', lineno) self.last_lineno = lineno return 1 return 0 # The first few visitor methods handle nodes that generator new # code objects def visitModule(self, node): lnf = walk(node.node, LocalNameFinder(), 0) self.locals.push(lnf.getLocals()) self.setDocstring(node.doc) self.visit(node.node) self.emit('LOAD_CONST', None) self.emit('RETURN_VALUE') def visitFunction(self, node): self._visitFuncOrLambda(node, isLambda=0) self.storeName(node.name) def visitLambda(self, node): self._visitFuncOrLambda(node, isLambda=1) def _visitFuncOrLambda(self, node, isLambda): gen = FunctionCodeGenerator(node, self.filename, isLambda) walk(node.code, gen) gen.finish() self.set_lineno(node) for default in node.defaults: self.visit(default) self.emit('LOAD_CONST', gen) self.emit('MAKE_FUNCTION', len(node.defaults)) def visitClass(self, node): gen = ClassCodeGenerator(node, self.filename) walk(node.code, gen) gen.finish() self.set_lineno(node) self.emit('LOAD_CONST', node.name) for base in node.bases: self.visit(base) self.emit('BUILD_TUPLE', len(node.bases)) self.emit('LOAD_CONST', gen.getCode()) self.emit('MAKE_FUNCTION', 0) self.emit('CALL_FUNCTION', 0) self.emit('BUILD_CLASS') self.storeName(node.name) # The rest are standard visitor methods # The next few implement control-flow statements def visitIf(self, node): end = self.newBlock() numtests = len(node.tests) for i in range(numtests): test, suite = node.tests[i] self.set_lineno(test) self.visit(test) nextTest = self.newBlock() self.emit('JUMP_IF_FALSE', nextTest) self.nextBlock() self.emit('POP_TOP') self.visit(suite) self.emit('JUMP_FORWARD', end) self.startBlock(nextTest) self.emit('POP_TOP') if node.else_: self.visit(node.else_) self.nextBlock(end) def visitWhile(self, node): self.set_lineno(node) loop = self.newBlock() else_ = self.newBlock() after = self.newBlock() self.emit('SETUP_LOOP', after) self.nextBlock(loop) self.loops.push(loop) self.set_lineno(node) self.visit(node.test) self.emit('JUMP_IF_FALSE', else_ or after) self.nextBlock() self.emit('POP_TOP') self.visit(node.body) self.emit('JUMP_ABSOLUTE', loop) self.startBlock(else_) # or just the POPs if not else clause self.emit('POP_TOP') self.emit('POP_BLOCK') if node.else_: self.visit(node.else_) self.loops.pop() self.nextBlock(after) def visitFor(self, node): start = self.newBlock() anchor = self.newBlock() after = self.newBlock() self.loops.push(start) self.set_lineno(node) self.emit('SETUP_LOOP', after) self.visit(node.list) self.visit(ast.Const(0)) self.nextBlock(start) self.set_lineno(node) self.emit('FOR_LOOP', anchor) self.nextBlock() self.visit(node.assign) self.visit(node.body) self.emit('JUMP_ABSOLUTE', start) self.startBlock(anchor) self.emit('POP_BLOCK') if node.else_: self.visit(node.else_) self.loops.pop() self.nextBlock(after) def visitBreak(self, node): if not self.loops: raise SyntaxError, "'break' outside loop (%s, %d)" % \ (self.filename, node.lineno) self.set_lineno(node) self.emit('BREAK_LOOP') def visitContinue(self, node): if not self.loops: raise SyntaxError, "'continue' outside loop (%s, %d)" % \ (self.filename, node.lineno) l = self.loops.top() self.set_lineno(node) self.emit('JUMP_ABSOLUTE', l) self.nextBlock() def visitTest(self, node, jump): end = self.newBlock() for child in node.nodes[:-1]: self.visit(child) self.emit(jump, end) self.nextBlock() self.emit('POP_TOP') self.visit(node.nodes[-1]) self.nextBlock(end) def visitAnd(self, node): self.visitTest(node, 'JUMP_IF_FALSE') def visitOr(self, node): self.visitTest(node, 'JUMP_IF_TRUE') def visitCompare(self, node): self.visit(node.expr) cleanup = self.newBlock() for op, code in node.ops[:-1]: self.visit(code) self.emit('DUP_TOP') self.emit('ROT_THREE') self.emit('COMPARE_OP', op) self.emit('JUMP_IF_FALSE', cleanup) self.nextBlock() self.emit('POP_TOP') # now do the last comparison if node.ops: op, code = node.ops[-1] self.visit(code) self.emit('COMPARE_OP', op) if len(node.ops) > 1: end = self.newBlock() self.emit('JUMP_FORWARD', end) self.startBlock(cleanup) self.emit('ROT_TWO') self.emit('POP_TOP') self.nextBlock(end) # list comprehensions __list_count = 0 def visitListComp(self, node): # XXX would it be easier to transform the AST into the form it # would have if the list comp were expressed as a series of # for and if stmts and an explicit append? self.set_lineno(node) # setup list append = "$append%d" % self.__list_count self.__list_count = self.__list_count + 1 self.emit('BUILD_LIST', 0) self.emit('DUP_TOP') self.emit('LOAD_ATTR', 'append') self.storeName(append) l = len(node.quals) stack = [] for i, for_ in zip(range(l), node.quals): start, anchor = self.visit(for_) cont = None for if_ in for_.ifs: if cont is None: cont = self.newBlock() self.visit(if_, cont) stack.insert(0, (start, cont, anchor)) self.loadName(append) self.visit(node.expr) self.emit('CALL_FUNCTION', 1) self.emit('POP_TOP') for start, cont, anchor in stack: if cont: skip_one = self.newBlock() self.emit('JUMP_FORWARD', skip_one) self.startBlock(cont) self.emit('POP_TOP') self.nextBlock(skip_one) self.emit('JUMP_ABSOLUTE', start) self.startBlock(anchor) self.delName(append) self.__list_count = self.__list_count - 1 def visitListCompFor(self, node): self.set_lineno(node) start = self.newBlock() anchor = self.newBlock() self.visit(node.list) self.visit(ast.Const(0)) self.emit('SET_LINENO', node.lineno) self.nextBlock(start) self.emit('FOR_LOOP', anchor) self.nextBlock() self.visit(node.assign) return start, anchor def visitListCompIf(self, node, branch): self.set_lineno(node) self.visit(node.test) self.emit('JUMP_IF_FALSE', branch) self.newBlock() self.emit('POP_TOP') # exception related def visitAssert(self, node): # XXX would be interesting to implement this via a # transformation of the AST before this stage end = self.newBlock() self.set_lineno(node) # XXX __debug__ and AssertionError appear to be special cases # -- they are always loaded as globals even if there are local # names. I guess this is a sort of renaming op. self.emit('LOAD_GLOBAL', '__debug__') self.emit('JUMP_IF_FALSE', end) self.nextBlock() self.emit('POP_TOP') self.visit(node.test) self.emit('JUMP_IF_TRUE', end) self.nextBlock() self.emit('POP_TOP') self.emit('LOAD_GLOBAL', 'AssertionError') if node.fail: self.visit(node.fail) self.emit('RAISE_VARARGS', 2) else: self.emit('RAISE_VARARGS', 1) self.nextBlock(end) self.emit('POP_TOP') def visitRaise(self, node): self.set_lineno(node) n = 0 if node.expr1: self.visit(node.expr1) n = n + 1 if node.expr2: self.visit(node.expr2) n = n + 1 if node.expr3: self.visit(node.expr3) n = n + 1 self.emit('RAISE_VARARGS', n) def visitTryExcept(self, node): handlers = self.newBlock() end = self.newBlock() if node.else_: lElse = self.newBlock() else: lElse = end self.set_lineno(node) self.emit('SETUP_EXCEPT', handlers) self.nextBlock() self.visit(node.body) self.emit('POP_BLOCK') self.emit('JUMP_FORWARD', lElse) self.startBlock(handlers) last = len(node.handlers) - 1 for i in range(len(node.handlers)): expr, target, body = node.handlers[i] self.set_lineno(expr) if expr: self.emit('DUP_TOP') self.visit(expr) self.emit('COMPARE_OP', 'exception match') next = self.newBlock() self.emit('JUMP_IF_FALSE', next) self.nextBlock() self.emit('POP_TOP') self.emit('POP_TOP') if target: self.visit(target) else: self.emit('POP_TOP') self.emit('POP_TOP') self.visit(body) self.emit('JUMP_FORWARD', end) if expr: self.nextBlock(next) else: self.nextBlock() self.emit('POP_TOP') self.emit('END_FINALLY') if node.else_: self.nextBlock(lElse) self.visit(node.else_) self.nextBlock(end) def visitTryFinally(self, node): final = self.newBlock() self.set_lineno(node) self.emit('SETUP_FINALLY', final) self.nextBlock() self.visit(node.body) self.emit('POP_BLOCK') self.emit('LOAD_CONST', None) self.nextBlock(final) self.visit(node.final) self.emit('END_FINALLY') # misc def visitDiscard(self, node): self.visit(node.expr) self.emit('POP_TOP') def visitConst(self, node): self.emit('LOAD_CONST', node.value) def visitKeyword(self, node): self.emit('LOAD_CONST', node.name) self.visit(node.expr) def visitGlobal(self, node): # no code to generate pass def visitName(self, node): self.set_lineno(node) self.loadName(node.name) def visitPass(self, node): self.set_lineno(node) def visitImport(self, node): self.set_lineno(node) for name, alias in node.names: if VERSION > 1: self.emit('LOAD_CONST', None) self.emit('IMPORT_NAME', name) mod = string.split(name, ".")[0] self.storeName(alias or mod) def visitFrom(self, node): self.set_lineno(node) fromlist = map(lambda (name, alias): name, node.names) if VERSION > 1: self.emit('LOAD_CONST', tuple(fromlist)) self.emit('IMPORT_NAME', node.modname) for name, alias in node.names: if VERSION > 1: if name == '*': self.namespace = 0 self.emit('IMPORT_STAR') # There can only be one name w/ from ... import * assert len(node.names) == 1 return else: self.emit('IMPORT_FROM', name) self._resolveDots(name) self.storeName(alias or name) else: self.emit('IMPORT_FROM', name) self.emit('POP_TOP') def _resolveDots(self, name): elts = string.split(name, ".") if len(elts) == 1: return for elt in elts[1:]: self.emit('LOAD_ATTR', elt) def visitGetattr(self, node): self.visit(node.expr) self.emit('LOAD_ATTR', node.attrname) # next five implement assignments def visitAssign(self, node): self.set_lineno(node) self.visit(node.expr) dups = len(node.nodes) - 1 for i in range(len(node.nodes)): elt = node.nodes[i] if i < dups: self.emit('DUP_TOP') if isinstance(elt, ast.Node): self.visit(elt) def visitAssName(self, node): if node.flags == 'OP_ASSIGN': self.storeName(node.name) elif node.flags == 'OP_DELETE': self.delName(node.name) else: print "oops", node.flags def visitAssAttr(self, node): self.visit(node.expr) if node.flags == 'OP_ASSIGN': self.emit('STORE_ATTR', node.attrname) elif node.flags == 'OP_DELETE': self.emit('DELETE_ATTR', node.attrname) else: print "warning: unexpected flags:", node.flags print node def _visitAssSequence(self, node, op='UNPACK_SEQUENCE'): if findOp(node) != 'OP_DELETE': self.emit(op, len(node.nodes)) for child in node.nodes: self.visit(child) if VERSION > 1: visitAssTuple = _visitAssSequence visitAssList = _visitAssSequence else: def visitAssTuple(self, node): self._visitAssSequence(node, 'UNPACK_TUPLE') def visitAssList(self, node): self._visitAssSequence(node, 'UNPACK_LIST') # augmented assignment def visitAugAssign(self, node): aug_node = wrap_aug(node.node) self.visit(aug_node, "load") self.visit(node.expr) self.emit(self._augmented_opcode[node.op]) self.visit(aug_node, "store") _augmented_opcode = { '+=' : 'INPLACE_ADD', '-=' : 'INPLACE_SUBTRACT', '*=' : 'INPLACE_MULTIPLY', '/=' : 'INPLACE_DIVIDE', '%=' : 'INPLACE_MODULO', '**=': 'INPLACE_POWER', '>>=': 'INPLACE_RSHIFT', '<<=': 'INPLACE_LSHIFT', '&=' : 'INPLACE_AND', '^=' : 'INPLACE_XOR', '|=' : 'INPLACE_OR', } def visitAugName(self, node, mode): if mode == "load": self.loadName(node.name) elif mode == "store": self.storeName(node.name) def visitAugGetattr(self, node, mode): if mode == "load": self.visit(node.expr) self.emit('DUP_TOP') self.emit('LOAD_ATTR', node.attrname) elif mode == "store": self.emit('ROT_TWO') self.emit('STORE_ATTR', node.attrname) def visitAugSlice(self, node, mode): if mode == "load": self.visitSlice(node, 1) elif mode == "store": slice = 0 if node.lower: slice = slice | 1 if node.upper: slice = slice | 2 if slice == 0: self.emit('ROT_TWO') elif slice == 3: self.emit('ROT_FOUR') else: self.emit('ROT_THREE') self.emit('STORE_SLICE+%d' % slice) def visitAugSubscript(self, node, mode): if len(node.subs) > 1: raise SyntaxError, "augmented assignment to tuple is not possible" if mode == "load": self.visitSubscript(node, 1) elif mode == "store": self.emit('ROT_THREE') self.emit('STORE_SUBSCR') def visitExec(self, node): self.visit(node.expr) if node.locals is None: self.emit('LOAD_CONST', None) else: self.visit(node.locals) if node.globals is None: self.emit('DUP_TOP') else: self.visit(node.globals) self.emit('EXEC_STMT') def visitCallFunc(self, node): pos = 0 kw = 0 self.set_lineno(node) self.visit(node.node) for arg in node.args: self.visit(arg) if isinstance(arg, ast.Keyword): kw = kw + 1 else: pos = pos + 1 if node.star_args is not None: self.visit(node.star_args) if node.dstar_args is not None: self.visit(node.dstar_args) have_star = node.star_args is not None have_dstar = node.dstar_args is not None opcode = callfunc_opcode_info[have_star, have_dstar] self.emit(opcode, kw << 8 | pos) def visitPrint(self, node): self.set_lineno(node) if node.dest: self.visit(node.dest) for child in node.nodes: if node.dest: self.emit('DUP_TOP') self.visit(child) if node.dest: self.emit('ROT_TWO') self.emit('PRINT_ITEM_TO') else: self.emit('PRINT_ITEM') def visitPrintnl(self, node): self.visitPrint(node) if node.dest: self.emit('PRINT_NEWLINE_TO') else: self.emit('PRINT_NEWLINE') def visitReturn(self, node): self.set_lineno(node) self.visit(node.value) self.emit('RETURN_VALUE') # slice and subscript stuff def visitSlice(self, node, aug_flag=None): # aug_flag is used by visitAugSlice self.visit(node.expr) slice = 0 if node.lower: self.visit(node.lower) slice = slice | 1 if node.upper: self.visit(node.upper) slice = slice | 2 if aug_flag: if slice == 0: self.emit('DUP_TOP') elif slice == 3: self.emit('DUP_TOPX', 3) else: self.emit('DUP_TOPX', 2) if node.flags == 'OP_APPLY': self.emit('SLICE+%d' % slice) elif node.flags == 'OP_ASSIGN': self.emit('STORE_SLICE+%d' % slice) elif node.flags == 'OP_DELETE': self.emit('DELETE_SLICE+%d' % slice) else: print "weird slice", node.flags raise def visitSubscript(self, node, aug_flag=None): self.visit(node.expr) for sub in node.subs: self.visit(sub) if aug_flag: self.emit('DUP_TOPX', 2) if len(node.subs) > 1: self.emit('BUILD_TUPLE', len(node.subs)) if node.flags == 'OP_APPLY': self.emit('BINARY_SUBSCR') elif node.flags == 'OP_ASSIGN': self.emit('STORE_SUBSCR') elif node.flags == 'OP_DELETE': self.emit('DELETE_SUBSCR') # binary ops def binaryOp(self, node, op): self.visit(node.left) self.visit(node.right) self.emit(op) def visitAdd(self, node): return self.binaryOp(node, 'BINARY_ADD') def visitSub(self, node): return self.binaryOp(node, 'BINARY_SUBTRACT') def visitMul(self, node): return self.binaryOp(node, 'BINARY_MULTIPLY') def visitDiv(self, node): return self.binaryOp(node, 'BINARY_DIVIDE') def visitMod(self, node): return self.binaryOp(node, 'BINARY_MODULO') def visitPower(self, node): return self.binaryOp(node, 'BINARY_POWER') def visitLeftShift(self, node): return self.binaryOp(node, 'BINARY_LSHIFT') def visitRightShift(self, node): return self.binaryOp(node, 'BINARY_RSHIFT') # unary ops def unaryOp(self, node, op): self.visit(node.expr) self.emit(op) def visitInvert(self, node): return self.unaryOp(node, 'UNARY_INVERT') def visitUnarySub(self, node): return self.unaryOp(node, 'UNARY_NEGATIVE') def visitUnaryAdd(self, node): return self.unaryOp(node, 'UNARY_POSITIVE') def visitUnaryInvert(self, node): return self.unaryOp(node, 'UNARY_INVERT') def visitNot(self, node): return self.unaryOp(node, 'UNARY_NOT') def visitBackquote(self, node): return self.unaryOp(node, 'UNARY_CONVERT') # bit ops def bitOp(self, nodes, op): self.visit(nodes[0]) for node in nodes[1:]: self.visit(node) self.emit(op) def visitBitand(self, node): return self.bitOp(node.nodes, 'BINARY_AND') def visitBitor(self, node): return self.bitOp(node.nodes, 'BINARY_OR') def visitBitxor(self, node): return self.bitOp(node.nodes, 'BINARY_XOR') # object constructors def visitEllipsis(self, node): self.emit('LOAD_CONST', Ellipsis) def visitTuple(self, node): for elt in node.nodes: self.visit(elt) self.emit('BUILD_TUPLE', len(node.nodes)) def visitList(self, node): for elt in node.nodes: self.visit(elt) self.emit('BUILD_LIST', len(node.nodes)) def visitSliceobj(self, node): for child in node.nodes: self.visit(child) self.emit('BUILD_SLICE', len(node.nodes)) def visitDict(self, node): lineno = getattr(node, 'lineno', None) if lineno: set.emit('SET_LINENO', lineno) self.emit('BUILD_MAP', 0) for k, v in node.items: lineno2 = getattr(node, 'lineno', None) if lineno2 is not None and lineno != lineno2: self.emit('SET_LINENO', lineno2) lineno = lineno2 self.emit('DUP_TOP') self.visit(v) self.emit('ROT_TWO') self.visit(k) self.emit('STORE_SUBSCR') class ModuleCodeGenerator(CodeGenerator): super_init = CodeGenerator.__init__ def __init__(self, filename): # XXX is ? in compile.c self.graph = pyassem.PyFlowGraph("", filename) self.super_init(filename) class FunctionCodeGenerator(CodeGenerator): super_init = CodeGenerator.__init__ optimized = 1 lambdaCount = 0 def __init__(self, func, filename, isLambda=0): if isLambda: klass = FunctionCodeGenerator name = "" % klass.lambdaCount klass.lambdaCount = klass.lambdaCount + 1 else: name = func.name args, hasTupleArg = generateArgList(func.argnames) self.graph = pyassem.PyFlowGraph(name, filename, args, optimized=1) self.isLambda = isLambda self.super_init(filename) lnf = walk(func.code, LocalNameFinder(args), 0) self.locals.push(lnf.getLocals()) if func.varargs: self.graph.setFlag(CO_VARARGS) if func.kwargs: self.graph.setFlag(CO_VARKEYWORDS) self.set_lineno(func) if hasTupleArg: self.generateArgUnpack(func.argnames) def finish(self): self.graph.startExitBlock() if not self.isLambda: self.emit('LOAD_CONST', None) self.emit('RETURN_VALUE') def generateArgUnpack(self, args): count = 0 for arg in args: if type(arg) == types.TupleType: self.emit('LOAD_FAST', '.nested%d' % count) count = count + 1 self.unpackSequence(arg) def unpackSequence(self, tup): if VERSION > 1: self.emit('UNPACK_SEQUENCE', len(tup)) else: self.emit('UNPACK_TUPLE', len(tup)) for elt in tup: if type(elt) == types.TupleType: self.unpackSequence(elt) else: self.emit('STORE_FAST', elt) unpackTuple = unpackSequence class ClassCodeGenerator(CodeGenerator): super_init = CodeGenerator.__init__ def __init__(self, klass, filename): self.graph = pyassem.PyFlowGraph(klass.name, filename, optimized=0) self.super_init(filename) lnf = walk(klass.code, LocalNameFinder(), 0) self.locals.push(lnf.getLocals()) self.graph.setFlag(CO_NEWLOCALS) def finish(self): self.graph.startExitBlock() self.emit('LOAD_LOCALS') self.emit('RETURN_VALUE') def generateArgList(arglist): """Generate an arg list marking TupleArgs""" args = [] extra = [] count = 0 for elt in arglist: if type(elt) == types.StringType: args.append(elt) elif type(elt) == types.TupleType: args.append(TupleArg(count, elt)) count = count + 1 extra.extend(misc.flatten(elt)) else: raise ValueError, "unexpect argument type:", elt return args + extra, count class LocalNameFinder: """Find local names in scope""" def __init__(self, names=()): self.names = misc.Set() self.globals = misc.Set() for name in names: self.names.add(name) def getLocals(self): for elt in self.globals.elements(): if self.names.has_elt(elt): self.names.remove(elt) return self.names def visitDict(self, node): pass def visitGlobal(self, node): for name in node.names: self.globals.add(name) def visitFunction(self, node): self.names.add(node.name) def visitLambda(self, node): pass def visitImport(self, node): for name, alias in node.names: self.names.add(alias or name) def visitFrom(self, node): for name, alias in node.names: self.names.add(alias or name) def visitClass(self, node): self.names.add(node.name) def visitAssName(self, node): self.names.add(node.name) def findOp(node): """Find the op (DELETE, LOAD, STORE) in an AssTuple tree""" v = OpFinder() walk(node, v, 0) return v.op class OpFinder: def __init__(self): self.op = None def visitAssName(self, node): if self.op is None: self.op = node.flags elif self.op != node.flags: raise ValueError, "mixed ops in stmt" class Delegator: """Base class to support delegation for augmented assignment nodes To generator code for augmented assignments, we use the following wrapper classes. In visitAugAssign, the left-hand expression node is visited twice. The first time the visit uses the normal method for that node . The second time the visit uses a different method that generates the appropriate code to perform the assignment. These delegator classes wrap the original AST nodes in order to support the variant visit methods. """ def __init__(self, obj): self.obj = obj def __getattr__(self, attr): return getattr(self.obj, attr) class AugGetattr(Delegator): pass class AugName(Delegator): pass class AugSlice(Delegator): pass class AugSubscript(Delegator): pass wrapper = { ast.Getattr: AugGetattr, ast.Name: AugName, ast.Slice: AugSlice, ast.Subscript: AugSubscript, } def wrap_aug(node): return wrapper[node.__class__](node) if __name__ == "__main__": import sys for file in sys.argv[1:]: compile(file)