/*
 * param.pro -- 5/6/'86
 *
 * this program demonstrates how to access the command line
 * parameters from a turbo prolog program.  
 *
 * we use a dos function $62 if the version of dos is
 * 3.0 or greater, and function $51 for 2.xx (an undocumented
 * function)  the potential problem is that certain nameless
 * programs install themselves on function $51, so be warned.
 */

include "EXAMPL66.PRO" /* This example includes some */
                       /* handy DOS routines */

domains
    strlist = string*
predicates
    write_list(strlist)
   
clauses
    write_list([]).
    write_list([H|T]) :-
        write(H, " "),
        write_list(T).
    
predicates
    get_psp(integer)
    get_params(string, integer)
    m_p(string, integer, integer, strlist, strlist)
    cmd_line(integer, strlist)
    append(strlist, strlist, strlist)

clauses
    /* get the psp segment 
     * first clause is for version 3.0 or higher
     */
    get_psp(PSP) :-
        dosver(Version),
        Version >= 3.0, 
        !,
        bios($21,reg($6200,0,0,0,0,0,0,0),
                 reg(_,PSP,_,_,_,_,_,_)).
    /* for version 2.xx */
    get_psp(PSP) :-
        !,
        bios($21,reg($5100,0,0,0,0,0,0,0),
                 reg(_,PSP,_,_,_,_,_,_)).
   
    /* get parameter vector */  
    get_params(P_string, PSP) :-
        ptr_dword(P, PSP, $81),
        frontchar(P, _, P_string).

    /* split vector into list of strings */
    m_p(P, Ac, Ac, Av, Av) :-
       frontchar(P, C, _),
       char_int(C, N),
       N = 13.
    m_p(P, Ac, T, Av, V) :-
       fronttoken(P, S1, P1),
       !,
       append(V, [S1], V1),
       T1 = T + 1,
       m_p(P1, Ac, T1, Av, V1).
        
    /* make typical argc, argv form for convience */
    cmd_line(Argc, Argv) :-
       get_psp(PSP),
       get_params(P, PSP),
       m_p(P, Argc, 0, Argv, []).

    
    append([], X, X).
    append([H|T], L1, [H|L2]) :-
        append(T, L1, L2).
   
goal
    clearwindow,
    cmd_line(Ac, Av),
    write(Ac), nl,
    write_list(Av), nl.