def _import_and_bind(self, imp):
"""Generates code that imports a module and binds it to a variable.
Args:
imp: Import object representing an import of the form "import x.y.z" or
"from x.y import z". Expects only a single binding.
"""
# Acquire handles to the Code objects in each Go package and call
# ImportModule to initialize all modules.
with self.block.alloc_temp() as mod, \
self.block.alloc_temp('[]*πg.Object') as mod_slice:
self.writer.write_checked_call2(
mod_slice, 'πg.ImportModule(πF, {})', util.go_str(imp.name))
# Bind the imported modules or members to variables in the current scope.
for binding in imp.bindings:
if binding.bind_type == imputil.Import.MODULE:
self.writer.write('{} = {}[{}]'.format(
mod.name, mod_slice.expr, binding.value))
self.block.bind_var(self.writer, binding.alias, mod.expr)
else:
self.writer.write('{} = {}[{}]'.format(
mod.name, mod_slice.expr, imp.name.count('.')))
# Binding a member of the imported module.
with self.block.alloc_temp() as member:
self.writer.write_checked_call2(
member, 'πg.GetAttr(πF, {}, {}, nil)',
mod.expr, self.block.root.intern(binding.value))
self.block.bind_var(self.writer, binding.alias, member.expr)
def visit_Str(self, node):
if isinstance(node.s, unicode):
expr_str = 'πg.NewUnicode({}).ToObject()'.format(
util.go_str(node.s.encode('utf-8')))
else:
expr_str = '{}.ToObject()'.format(self.block.root.intern(node.s))
return expr.GeneratedLiteral(expr_str)
def del_var(self, writer, name):
var = self.vars.get(name)
if not var:
raise util.ParseError(
None, 'cannot delete nonexistent local: {}'.format(name))
if var.type == Var.TYPE_GLOBAL:
return self.root.del_var(writer, name)
adjusted_name = util.adjust_local_name(name)
# Resolve local first to ensure the variable is already bound.
writer.write_checked_call1('πg.CheckLocal(πF, {}, {})', adjusted_name,
util.go_str(name))
writer.write('{} = πg.UnboundLocal'.format(adjusted_name))
def resolve_name(self, writer, name):
block = self
while not isinstance(block, ModuleBlock):
if isinstance(block, FunctionBlock):
var = block.vars.get(name)
if var:
if var.type == Var.TYPE_GLOBAL:
return self._resolve_global(writer, name)
writer.write_checked_call1('πg.CheckLocal(πF, {}, {})',
util.adjust_local_name(name),
util.go_str(name))
return expr.GeneratedLocalVar(name)
block = block.parent
return self._resolve_global(writer, name)
def visit_Call(self, node):
# Build positional arguments.
args = expr.nil_expr
if node.args:
args = self.block.alloc_temp('[]*πg.Object')
self.writer.write('{} = πF.MakeArgs({})'.format(
args.expr, len(node.args)))
for i, n in enumerate(node.args):
with self.visit(n) as a:
self.writer.write('{}[{}] = {}'.format(
args.expr, i, a.expr))
varg = expr.nil_expr
if node.starargs:
varg = self.visit(node.starargs)
# Build keyword arguments
keywords = expr.nil_expr
if node.keywords:
values = []
for k in node.keywords:
values.append((util.go_str(k.arg), self.visit(k.value)))
keywords = self.block.alloc_temp('πg.KWArgs')
self.writer.write_tmpl('$keywords = πg.KWArgs{',
keywords=keywords.name)
with self.writer.indent_block():
for k, v in values:
with v:
self.writer.write_tmpl('{$name, $value},',
name=k,
value=v.expr)
self.writer.write('}')
kwargs = expr.nil_expr
if node.kwargs:
kwargs = self.visit(node.kwargs)
# Invoke function with all parameters.
with args, varg, keywords, kwargs, self.visit(node.func) as func:
result = self.block.alloc_temp()
if varg is expr.nil_expr and kwargs is expr.nil_expr:
self.writer.write_checked_call2(result, '{}.Call(πF, {}, {})',
func.expr, args.expr,
keywords.expr)
else:
self.writer.write_checked_call2(
result, 'πg.Invoke(πF, {}, {}, {}, {}, {})', func.expr,
args.expr, varg.expr, keywords.expr, kwargs.expr)
if node.args:
self.writer.write('πF.FreeArgs({})'.format(args.expr))
return result
def intern(self, s):
if len(s) > 64 or _non_word_re.search(s):
return 'πg.NewStr({})'.format(util.go_str(s))
self.strings.add(s)
return 'ß' + s
def visit_ClassDef(self, node):
# Since we only care about global vars, we end up throwing away the locals
# collected by BlockVisitor. But use it anyway since it buys us detection of
# assignment to vars that are later declared global.
block_visitor = block.BlockVisitor()
for child in node.body:
block_visitor.visit(child)
global_vars = {v.name for v in block_visitor.vars.values()
if v.type == block.Var.TYPE_GLOBAL}
# Visit all the statements inside body of the class definition.
body_visitor = StatementVisitor(block.ClassBlock(
self.block, node.name, global_vars), self.future_node)
# Indent so that the function body is aligned with the goto labels.
with body_visitor.writer.indent_block():
body_visitor._visit_each(node.body) # pylint: disable=protected-access
self._write_py_context(node.lineno)
with self.block.alloc_temp('*πg.Dict') as cls, \
self.block.alloc_temp() as mod_name, \
self.block.alloc_temp('[]*πg.Object') as bases, \
self.block.alloc_temp() as meta:
self.writer.write('{} = make([]*πg.Object, {})'.format(
bases.expr, len(node.bases)))
for i, b in enumerate(node.bases):
with self.visit_expr(b) as b:
self.writer.write('{}[{}] = {}'.format(bases.expr, i, b.expr))
self.writer.write('{} = πg.NewDict()'.format(cls.name))
self.writer.write_checked_call2(
mod_name, 'πF.Globals().GetItem(πF, {}.ToObject())',
self.block.root.intern('__name__'))
self.writer.write_checked_call1(
'{}.SetItem(πF, {}.ToObject(), {})',
cls.expr, self.block.root.intern('__module__'), mod_name.expr)
tmpl = textwrap.dedent("""
_, πE = πg.NewCode($name, $filename, nil, 0, func(πF *πg.Frame, _ []*πg.Object) (*πg.Object, *πg.BaseException) {
\tπClass := $cls
\t_ = πClass""")
self.writer.write_tmpl(tmpl, name=util.go_str(node.name),
filename=util.go_str(self.block.root.filename),
cls=cls.expr)
with self.writer.indent_block():
self.writer.write_temp_decls(body_visitor.block)
self.writer.write_block(body_visitor.block,
body_visitor.writer.getvalue())
self.writer.write('return nil, nil')
tmpl = textwrap.dedent("""\
}).Eval(πF, πF.Globals(), nil, nil)
if πE != nil {
\tcontinue
}
if $meta, πE = $cls.GetItem(πF, $metaclass_str.ToObject()); πE != nil {
\tcontinue
}
if $meta == nil {
\t$meta = πg.TypeType.ToObject()
}""")
self.writer.write_tmpl(
tmpl, meta=meta.name, cls=cls.expr,
metaclass_str=self.block.root.intern('__metaclass__'))
with self.block.alloc_temp() as type_:
type_expr = ('{}.Call(πF, []*πg.Object{{πg.NewStr({}).ToObject(), '
'πg.NewTuple({}...).ToObject(), {}.ToObject()}}, nil)')
self.writer.write_checked_call2(
type_, type_expr, meta.expr,
util.go_str(node.name), bases.expr, cls.expr)
self.block.bind_var(self.writer, node.name, type_.expr)
def visit_function_inline(self, node):
"""Returns an GeneratedExpr for a function with the given body."""
# First pass collects the names of locals used in this function. Do this in
# a separate pass so that we know whether to resolve a name as a local or a
# global during the second pass.
func_visitor = block.FunctionBlockVisitor(node)
for child in node.body:
func_visitor.visit(child)
func_block = block.FunctionBlock(self.block, node.name, func_visitor.vars,
func_visitor.is_generator)
visitor = StatementVisitor(func_block, self.future_node)
# Indent so that the function body is aligned with the goto labels.
with visitor.writer.indent_block():
visitor._visit_each(node.body) # pylint: disable=protected-access
result = self.block.alloc_temp()
with self.block.alloc_temp('[]πg.Param') as func_args:
args = node.args
argc = len(args.args)
self.writer.write('{} = make([]πg.Param, {})'.format(
func_args.expr, argc))
# The list of defaults only contains args for which a default value is
# specified so pad it with None to make it the same length as args.
defaults = [None] * (argc - len(args.defaults)) + args.defaults
for i, (a, d) in enumerate(zip(args.args, defaults)):
with self.visit_expr(d) if d else expr.nil_expr as default:
tmpl = '$args[$i] = πg.Param{Name: $name, Def: $default}'
self.writer.write_tmpl(tmpl, args=func_args.expr, i=i,
name=util.go_str(a.arg), default=default.expr)
flags = []
if args.vararg:
flags.append('πg.CodeFlagVarArg')
if args.kwarg:
flags.append('πg.CodeFlagKWArg')
# The function object gets written to a temporary writer because we need
# it as an expression that we subsequently bind to some variable.
self.writer.write_tmpl(
'$result = πg.NewFunction(πg.NewCode($name, $filename, $args, '
'$flags, func(πF *πg.Frame, πArgs []*πg.Object) '
'(*πg.Object, *πg.BaseException) {',
result=result.name, name=util.go_str(node.name),
filename=util.go_str(self.block.root.filename), args=func_args.expr,
flags=' | '.join(flags) if flags else 0)
with self.writer.indent_block():
for var in func_block.vars.values():
if var.type != block.Var.TYPE_GLOBAL:
fmt = 'var {0} *πg.Object = {1}; _ = {0}'
self.writer.write(fmt.format(
util.adjust_local_name(var.name), var.init_expr))
self.writer.write_temp_decls(func_block)
self.writer.write('var πR *πg.Object; _ = πR')
self.writer.write('var πE *πg.BaseException; _ = πE')
if func_block.is_generator:
self.writer.write(
'return πg.NewGenerator(πF, func(πSent *πg.Object) '
'(*πg.Object, *πg.BaseException) {')
with self.writer.indent_block():
self.writer.write_block(func_block, visitor.writer.getvalue())
self.writer.write('return nil, πE')
self.writer.write('}).ToObject(), nil')
else:
self.writer.write_block(func_block, visitor.writer.getvalue())
self.writer.write(textwrap.dedent("""\
if πE != nil {
\tπR = nil
} else if πR == nil {
\tπR = πg.None
}
return πR, πE"""))
self.writer.write('}), πF.Globals()).ToObject()')
return result
