Compiles a list of possible symbols that can hold a value in
        place. These consist of local vars, global vars, and functions.

def _complete_values(self, symbol = ""):
        """Compiles a list of possible symbols that can hold a value in
        place. These consist of local vars, global vars, and functions."""
        result = {}
        #Also add the subroutines from the module and its dependencies.
        moddict = self._generic_filter_execs(self.context.module)
        self._cond_update(result, moddict, symbol)
        self._cond_update(result, self.context.module.interfaces, symbol)
        for depend in self.context.module.dependencies:
            if depend in self.context.module.parent.modules:
                #We don't want to display executables that are part of an interface, or that are embedded in
                #a derived type, since those will be called through the type or interface
                filtdict = self._generic_filter_execs(self.context.module.parent.modules[depend])
                self._cond_update(result, filtdict, symbol)
                self._cond_update(result, self.context.module.parent.modules[depend].interfaces, symbol)

        #Add all the local vars if we are in an executable
        if (isinstance(self.context.element, Function) or 
            isinstance(self.context.element, Subroutine)):
            self._cond_update(result, self.element.members, symbol)
        #Next add the global variables from the module
        if self.context.module is not None:
            self._cond_update(result, self.context.module.members, symbol)
            #Next add user defined functions to the mix
            for execkey in self.context.module.executables:
                iexec = self.context.module.executables[execkey]
                if isinstance(iexec, Function) and self._symbol_in(symbol, iexec.name):
                    result[iexec.name] = iexec

        #Finally add the builtin functions to the mix. We need to add support
        #for these in a separate file so we have their call signatures.
        if symbol == "":
            #Use the abbreviated list of most common fortran builtins
            self._cond_update(result, cache.common_builtin, symbol)
        else:
            #we can use the full list as there will probably not be that
            #many left over.
            self._cond_update(result, cache.builtin, symbol)           
        
        return result