/*   SHS: Syntactically Homogeneous Shell
 *   Copyright (C) 2019  Aidan Hahn
 *
 *   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 <https://www.gnu.org/licenses/>.
 */

package shs

type Operation func(*Token) *Token

type Function struct {
    function Operation
    timesCalled int
    args   int
}

type FuncTable map[string]*Function

var (
    GlobalFuncTable *FuncTable
)

// TODO: Currently only checks arg list length
func ParseFunction(target *Function, args *Token) bool {
    // HANDLE EXEC
    if target.args < 0 {
        return true
    }

    i := target.args
    for iter := &args; *iter != nil; iter = &((*iter).next) {
        i -= 1
    }

    if i != 0 {
        // log error here?
        return false
    }

    return true
}

func CallFunction(target *Function, args *Token) *Token {
    if !ParseFunction(target, args) {
        return args
    }

    target.timesCalled += 1
    return target.function(args)
}

func GetFunction(arg string) *Function {
    target, ok := (*GlobalFuncTable)[arg]
    if !ok {
        // TODO: hook into stdlib exec call
        ;
    }

    return target
}