python-uncompyle6/uncompyle6/semantics/make_function2.py

#  Copyright (c) 2015-2019 by Rocky Bernstein
#  Copyright (c) 2000-2002 by hartmut Goebel <h.goebel@crazy-compilers.com>
#
#  This program is free software: you can redistribute it and/or modify
#  it under the terms of the GNU General Public License as published by
#  the Free Software Foundation, either version 3 of the License, or
#  (at your option) any later version.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#
#  You should have received a copy of the GNU General Public License
#  along with this program.  If not, see <http://www.gnu.org/licenses/>.
"""
All the crazy things we have to do to handle Python functions
"""
from xdis.code import iscode, code_has_star_arg, code_has_star_star_arg
from uncompyle6.scanner import Code
from uncompyle6.parsers.treenode import SyntaxTree
from uncompyle6 import PYTHON3
from uncompyle6.semantics.parser_error import ParserError
from uncompyle6.parser import ParserError as ParserError2
from uncompyle6.semantics.helper import (
    print_docstring,
    find_all_globals,
    find_globals_and_nonlocals,
    find_none,
)

if PYTHON3:
    from itertools import zip_longest
else:
    from itertools import izip_longest as zip_longest

from uncompyle6.show import maybe_show_tree_param_default

def make_function2(self, node, is_lambda, nested=1, code_node=None):
    """
    Dump function defintion, doc string, and function body.
    This code is specialied for Python 2.
    """

    # FIXME: call make_function3 if we are self.version >= 3.0
    # and then simplify the below.

    def build_param(ast, name, default):
        """build parameters:
            - handle defaults
            - handle format tuple parameters
        """
        # if formal parameter is a tuple, the paramater name
        # starts with a dot (eg. '.1', '.2')
        if name.startswith("."):
            # replace the name with the tuple-string
            name = self.get_tuple_parameter(ast, name)
            pass

        if default:
            value = self.traverse(default, indent="")
            maybe_show_tree_param_default(self.showast, name, value)
            result = "%s=%s" % (name, value)
            if result[-2:] == "= ":  # default was 'LOAD_CONST None'
                result += "None"
            return result
        else:
            return name

    # MAKE_FUNCTION_... or MAKE_CLOSURE_...
    assert node[-1].kind.startswith("MAKE_")

    args_node = node[-1]
    if isinstance(args_node.attr, tuple):
        # positional args are after kwargs
        defparams = node[1 : args_node.attr[0] + 1]
        pos_args, kw_args, annotate_argc = args_node.attr
    else:
        defparams = node[: args_node.attr]
        kw_args = 0
        pass

    lambda_index = None

    if lambda_index and is_lambda and iscode(node[lambda_index].attr):
        assert node[lambda_index].kind == "LOAD_LAMBDA"
        code = node[lambda_index].attr
    else:
        code = code_node.attr

    assert iscode(code)
    code = Code(code, self.scanner, self.currentclass)

    # add defaults values to parameter names
    argc = code.co_argcount
    paramnames = list(code.co_varnames[:argc])

    # defaults are for last n parameters, thus reverse
    paramnames.reverse()
    defparams.reverse()

    try:
        ast = self.build_ast(
            code._tokens,
            code._customize,
            is_lambda=is_lambda,
            noneInNames=("None" in code.co_names),
        )
    except (ParserError, ParserError2) as p:
        self.write(str(p))
        if not self.tolerate_errors:
            self.ERROR = p
        return

    kw_pairs = 0
    indent = self.indent

    # build parameters
    params = [
        build_param(ast, name, default)
        for name, default in zip_longest(paramnames, defparams, fillvalue=None)
    ]
    params.reverse()  # back to correct order

    if code_has_star_arg(code):
        params.append("*%s" % code.co_varnames[argc])
        argc += 1

    # dump parameter list (with default values)
    if is_lambda:
        self.write("lambda ", ", ".join(params))
        # If the last statement is None (which is the
        # same thing as "return None" in a lambda) and the
        # next to last statement is a "yield". Then we want to
        # drop the (return) None since that was just put there
        # to have something to after the yield finishes.
        # FIXME: this is a bit hoaky and not general
        if (
            len(ast) > 1
            and self.traverse(ast[-1]) == "None"
            and self.traverse(ast[-2]).strip().startswith("yield")
        ):
            del ast[-1]
            # Now pick out the expr part of the last statement
            ast_expr = ast[-1]
            while ast_expr.kind != "expr":
                ast_expr = ast_expr[0]
            ast[-1] = ast_expr
            pass
    else:
        self.write("(", ", ".join(params))

    if kw_args > 0:
        if not (4 & code.co_flags):
            if argc > 0:
                self.write(", *, ")
            else:
                self.write("*, ")
            pass
        else:
            self.write(", ")

        for n in node:
            if n == "pos_arg":
                continue
            else:
                self.preorder(n)
            break
        pass

    if code_has_star_star_arg(code):
        if argc > 0:
            self.write(", ")
        self.write("**%s" % code.co_varnames[argc + kw_pairs])

    if is_lambda:
        self.write(": ")
    else:
        self.println("):")

    if (
        len(code.co_consts) > 0 and code.co_consts[0] is not None and not is_lambda
    ):  # ugly
        # docstring exists, dump it
        print_docstring(self, indent, code.co_consts[0])

    code._tokens = None  # save memory
    if not is_lambda:
        assert ast == "stmts"

    all_globals = find_all_globals(ast, set())

    globals, nonlocals = find_globals_and_nonlocals(
        ast, set(), set(), code, self.version
    )

    # Python 2 doesn't support the "nonlocal" statement
    assert self.version >= 3.0 or not nonlocals

    for g in sorted((all_globals & self.mod_globs) | globals):
        self.println(self.indent, "global ", g)
    self.mod_globs -= all_globals
    has_none = "None" in code.co_names
    rn = has_none and not find_none(ast)
    self.gen_source(
        ast, code.co_name, code._customize, is_lambda=is_lambda, returnNone=rn
    )
    code._tokens = None
    code._customize = None  # save memory