| "Usage: unparse.py <path to source file>" |
| import sys |
| import math |
| import ast |
| import tokenize |
| import io |
| import os |
| |
| # Large float and imaginary literals get turned into infinities in the AST. |
| # We unparse those infinities to INFSTR. |
| INFSTR = "1e" + repr(sys.float_info.max_10_exp + 1) |
| |
| def interleave(inter, f, seq): |
| """Call f on each item in seq, calling inter() in between. |
| """ |
| seq = iter(seq) |
| try: |
| f(next(seq)) |
| 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 disregarded. """ |
| |
| 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("", file=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.level) |
| if t.module: |
| self.write(t.module) |
| self.write(" import ") |
| interleave(lambda: self.write(", "), self.dispatch, t.names) |
| |
| 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 ") |
| interleave(lambda: self.write(", "), 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 _Global(self, t): |
| self.fill("global ") |
| interleave(lambda: self.write(", "), self.write, t.names) |
| |
| def _Nonlocal(self, t): |
| self.fill("nonlocal ") |
| 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 not t.exc: |
| assert not t.cause |
| return |
| self.write(" ") |
| self.dispatch(t.exc) |
| if t.cause: |
| self.write(" from ") |
| self.dispatch(t.cause) |
| |
| 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): |
| if len(t.body) == 1 and isinstance(t.body[0], ast.TryExcept): |
| # try-except-finally |
| self.dispatch(t.body) |
| else: |
| 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(" as ") |
| self.write(t.name) |
| self.enter() |
| self.dispatch(t.body) |
| self.leave() |
| |
| def _ClassDef(self, t): |
| self.write("\n") |
| for deco in t.decorator_list: |
| self.fill("@") |
| self.dispatch(deco) |
| self.fill("class "+t.name) |
| self.write("(") |
| comma = False |
| for e in t.bases: |
| 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(")") |
| |
| 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(")") |
| if t.returns: |
| self.write(" -> ") |
| self.dispatch(t.returns) |
| 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() |
| self.dispatch(t.body) |
| self.leave() |
| # collapse nested ifs into equivalent elifs. |
| while (t.orelse and len(t.orelse) == 1 and |
| isinstance(t.orelse[0], ast.If)): |
| t = t.orelse[0] |
| self.fill("elif ") |
| self.dispatch(t.test) |
| self.enter() |
| self.dispatch(t.body) |
| self.leave() |
| # final else |
| 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 _Bytes(self, t): |
| self.write(repr(t.s)) |
| |
| def _Str(self, tree): |
| self.write(repr(tree.s)) |
| |
| def _Name(self, t): |
| self.write(t.id) |
| |
| def _Num(self, t): |
| # Substitute overflowing decimal literal for AST infinities. |
| self.write(repr(t.n).replace("inf", INFSTR)) |
| |
| 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 _SetComp(self, t): |
| self.write("{") |
| self.dispatch(t.elt) |
| for gen in t.generators: |
| self.dispatch(gen) |
| self.write("}") |
| |
| def _DictComp(self, t): |
| self.write("{") |
| self.dispatch(t.key) |
| self.write(": ") |
| self.dispatch(t.value) |
| 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 _Set(self, t): |
| assert(t.elts) # should be at least one element |
| self.write("{") |
| interleave(lambda: self.write(", "), self.dispatch, t.elts) |
| self.write("}") |
| |
| def _Dict(self, t): |
| self.write("{") |
| def write_pair(pair): |
| (k, v) = pair |
| self.dispatch(k) |
| self.write(": ") |
| self.dispatch(v) |
| interleave(lambda: self.write(", "), write_pair, 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.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) |
| # Special case: 3.__abs__() is a syntax error, so if t.value |
| # is an integer literal then we need to either parenthesize |
| # it or add an extra space to get 3 .__abs__(). |
| if isinstance(t.value, ast.Num) and isinstance(t.value.n, int): |
| self.write(" ") |
| 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("]") |
| |
| def _Starred(self, t): |
| self.write("*") |
| self.dispatch(t.value) |
| |
| # 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) |
| |
| # argument |
| def _arg(self, t): |
| self.write(t.arg) |
| if t.annotation: |
| self.write(": ") |
| self.dispatch(t.annotation) |
| |
| # others |
| def _arguments(self, t): |
| first = True |
| # normal arguments |
| defaults = [None] * (len(t.args) - len(t.defaults)) + t.defaults |
| for a, d in zip(t.args, defaults): |
| if first:first = False |
| else: self.write(", ") |
| self.dispatch(a) |
| if d: |
| self.write("=") |
| self.dispatch(d) |
| |
| # varargs, or bare '*' if no varargs but keyword-only arguments present |
| if t.vararg or t.kwonlyargs: |
| if first:first = False |
| else: self.write(", ") |
| self.write("*") |
| if t.vararg: |
| self.write(t.vararg) |
| if t.varargannotation: |
| self.write(": ") |
| self.dispatch(t.varargannotation) |
| |
| # keyword-only arguments |
| if t.kwonlyargs: |
| for a, d in zip(t.kwonlyargs, t.kw_defaults): |
| if first:first = False |
| else: self.write(", ") |
| self.dispatch(a), |
| if d: |
| self.write("=") |
| self.dispatch(d) |
| |
| # kwargs |
| if t.kwarg: |
| if first:first = False |
| else: self.write(", ") |
| self.write("**"+t.kwarg) |
| if t.kwargannotation: |
| self.write(": ") |
| self.dispatch(t.kwargannotation) |
| |
| def _keyword(self, t): |
| self.write(t.arg) |
| self.write("=") |
| self.dispatch(t.value) |
| |
| def _Lambda(self, t): |
| self.write("(") |
| self.write("lambda ") |
| self.dispatch(t.args) |
| self.write(": ") |
| self.dispatch(t.body) |
| self.write(")") |
| |
| def _alias(self, t): |
| self.write(t.name) |
| if t.asname: |
| self.write(" as "+t.asname) |
| |
| def roundtrip(filename, output=sys.stdout): |
| with open(filename, "rb") as pyfile: |
| encoding = tokenize.detect_encoding(pyfile.readline)[0] |
| with open(filename, "r", encoding=encoding) as pyfile: |
| source = pyfile.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("Directory not readable: %s" % a, file=sys.stderr) |
| else: |
| for n in names: |
| fullname = os.path.join(a, n) |
| if os.path.isfile(fullname): |
| output = io.StringIO() |
| print('Testing %s' % fullname) |
| try: |
| roundtrip(fullname, output) |
| except Exception as 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:]) |