argumentmapper.py

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#  Copyright 2008-2015 Nokia Networks
#  Copyright 2016-     Robot Framework Foundation
#
#  Licensed under the Apache License, Version 2.0 (the "License");
#  you may not use this file except in compliance with the License.
#  You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
#  Unless required by applicable law or agreed to in writing, software
#  distributed under the License is distributed on an "AS IS" BASIS,
#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#  See the License for the specific language governing permissions and
#  limitations under the License.
 
from robot.errors import DataError
 
 
class ArgumentMapper:
 
    
    def __init__(self, argspec):
        self._argspec_argspec = argspec
 
    def map(self, positional, named, replace_defaults=True):
        template = KeywordCallTemplate(self._argspec_argspec)
        template.fill_positional(positional)
        template.fill_named(named)
        if replace_defaults:
            template.replace_defaults()
        return template.args, template.kwargs
 
 
class KeywordCallTemplate:
 
    
    def __init__(self, argspec):
        self._argspec_argspec = argspec
        self.argsargs = [None if arg not in argspec.defaults
                     else DefaultValue(argspec.defaults[arg])
                     for arg in argspec.positional]
        self.kwargskwargs = []
 
    def fill_positional(self, positional):
        self.argsargs[:len(positional)] = positional
 
    def fill_named(self, named):
        spec = self._argspec_argspec
        for name, value in named:
            if name in spec.positional_or_named:
                index = spec.positional_or_named.index(name)
                self.argsargs[index] = value
            elif spec.var_named or name in spec.named_only:
                self.kwargskwargs.append((name, value))
            else:
                raise DataError("Non-existing named argument '%s'." % name)
        named_names = {name for name, _ in named}
        for name in spec.named_only:
            if name not in named_names:
                value = DefaultValue(spec.defaults[name])
                self.kwargskwargs.append((name, value))
 
    def replace_defaults(self):
        is_default = lambda arg: isinstance(arg, DefaultValue)
        while self.argsargs and is_default(self.argsargs[-1]):
            self.argsargs.pop()
        self.argsargs = [a if not is_default(a) else a.value for a in self.argsargs]
        self.kwargskwargs = [(n, v) for n, v in self.kwargskwargs if not is_default(v)]
 
 
class DefaultValue:
 
    def __init__(self, value):
        self.valuevalue = value
 
    def resolve(self, variables):
        try:
            return variables.replace_scalar(self.valuevalue)
        except DataError as err:
            raise DataError('Resolving argument default values failed: %s'
                            % err.message)