SHS/stdlib/list.go

/*   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 stdlib

import (
    "gitlab.com/whom/shs/ast"
    "gitlab.com/whom/shs/log"
)

/* EXPAND
 * Takes 1 element: a list
 * retuns a sequence of elements (list contents)
 * in event a not-list is passed in, returns the arg.
 */
func expand(input *ast.Token, vars ast.VarTable, funcs ast.FuncTable) *ast.Token {
    if input.Tag != ast.LIST {
        log.Log(log.DEBUG, "expand called on not a list", "expand")
        return input
    }

    return input.Inner.(*ast.Token)
}

/* L_APPEND (append from repl)
 * Appends N elements to the end of a list
 * Arg one is a list, next args are appended
 * if no args are a list, a list is made from all args
 */
func l_append(input *ast.Token, vars ast.VarTable, funcs ast.FuncTable) *ast.Token {
    src := input

    if input.Tag != ast.LIST {
        // TODO: position??
        return input
    }

    // deref inner first
    i := src.Inner.(*ast.Token)
    iter := &i
    if *iter == nil {
        src.Inner = input.Next
        src.Next = nil

    } else {
        for (*iter).Next != nil {
            iter = &((*iter).Next)
        }

        (*iter).Next = input.Next
        input.Next = nil
    }

    return src
}