path: root/eval.cpp

#include "eval.h"
#include "builtin.h"
#include "exc.h"
#include "consts.h"
#include <cstdio>

extern Pair *empty_list;
FrameObj *eval_stack[EVAL_STACK_SIZE];

void Evaluator::add_builtin_routines() {

#define ADD_ENTRY(name, rout) \
    envt->add_binding(new SymObj(name), rout)

#define ADD_BUILTIN_PROC(name, rout) \
    ADD_ENTRY(name, new BuiltinProcObj(rout, name))

    ADD_ENTRY("if", new SpecialOptIf());
    ADD_ENTRY("lambda", new SpecialOptLambda());
    ADD_ENTRY("define", new SpecialOptDefine());
    ADD_ENTRY("set!", new SpecialOptSet());
    ADD_ENTRY("quote", new SpecialOptQuote());
    ADD_ENTRY("eval", new SpecialOptEval());
    ADD_ENTRY("and", new SpecialOptAnd());

    ADD_BUILTIN_PROC("+", num_add);
    ADD_BUILTIN_PROC("-", num_sub);
    ADD_BUILTIN_PROC("*", num_mul);
    ADD_BUILTIN_PROC("/", num_div);

    ADD_BUILTIN_PROC("<", num_lt);
    ADD_BUILTIN_PROC("<=", num_le);
    ADD_BUILTIN_PROC(">", num_gt);
    ADD_BUILTIN_PROC(">=", num_ge);
    ADD_BUILTIN_PROC("=", num_eq);

    ADD_BUILTIN_PROC("exact?", num_is_exact);
    ADD_BUILTIN_PROC("inexact?", num_is_inexact);
    ADD_BUILTIN_PROC("number?", is_number);
    ADD_BUILTIN_PROC("complex?", is_complex);
    ADD_BUILTIN_PROC("real?", is_real);
    ADD_BUILTIN_PROC("rational?", is_rational);
    ADD_BUILTIN_PROC("integer?", is_integer);
    ADD_BUILTIN_PROC("abs", num_abs);
    ADD_BUILTIN_PROC("modulo", num_mod);
    ADD_BUILTIN_PROC("remainder", num_rem);
    ADD_BUILTIN_PROC("quotient", num_quo);
    ADD_BUILTIN_PROC("gcd", num_gcd);
    ADD_BUILTIN_PROC("lcm", num_lcm);


    ADD_BUILTIN_PROC("not", bool_not);
    ADD_BUILTIN_PROC("boolean?", is_boolean);

    ADD_BUILTIN_PROC("pair?", is_pair);
    ADD_BUILTIN_PROC("cons", make_pair);
    ADD_BUILTIN_PROC("car", pair_car);
    ADD_BUILTIN_PROC("cdr", pair_cdr);
    ADD_BUILTIN_PROC("set-car!", pair_set_car);
    ADD_BUILTIN_PROC("set-cdr!", pair_set_cdr);
    ADD_BUILTIN_PROC("null?", is_null);
    ADD_BUILTIN_PROC("list?", is_list);
    ADD_BUILTIN_PROC("list", make_list);
    ADD_BUILTIN_PROC("length", length);
    ADD_BUILTIN_PROC("append", append);
    ADD_BUILTIN_PROC("reverse", reverse);
    ADD_BUILTIN_PROC("list-tail", list_tail);

    ADD_BUILTIN_PROC("eqv?", is_eqv);
    ADD_BUILTIN_PROC("eq?", is_eqv);
    ADD_BUILTIN_PROC("equal?", is_equal);

    ADD_BUILTIN_PROC("display", display);
    ADD_BUILTIN_PROC("string?", is_string);
    ADD_BUILTIN_PROC("symbol?", is_symbol);
}

Evaluator::Evaluator() {
    envt = new Environment(NULL);       // Top-level Environment
    add_builtin_routines();
}

void push(Pair * &pc, FrameObj ** &top_ptr, Environment *envt) {
    if (pc->car->is_simple_obj())           // Not an opt invocation
    {
        *top_ptr = envt->get_obj(pc->car);  // Objectify the symbol
        top_ptr++;
        pc = pc->next;                      // Move to the next instruction
    }
    else                                    // Operational Invocation
    {
        if (pc->car == empty_list)
            throw NormalError(SYN_ERR_EMPTY_COMB);

        *top_ptr++ = new RetAddr(pc);       // Push the return address
        if (!is_list(TO_PAIR(pc->car)))
            throw TokenError(pc->car->ext_repr(), RUN_ERR_WRONG_NUM_OF_ARGS);
        // static_cast because of is_simple_obj() is false
        pc = static_cast<Pair*>(pc->car);  // Go deeper to enter the call
        envt->get_obj(pc->car)->prepare(pc);
    }
}

EvalObj *Evaluator::run_expr(Pair *prog) {
    FrameObj **top_ptr = eval_stack;
    Pair *pc = prog;
    Continuation *cont = NULL;
    // envt is this->envt
    push(pc, top_ptr, envt);

    while((*eval_stack)->is_ret_addr())
    {
        if (top_ptr == eval_stack + EVAL_STACK_SIZE)
            throw TokenError("Evaluation", RUN_ERR_STACK_OVERFLOW);
//        for (; pc && pc->skip; pc = pc->next);
        if (pc)
            push(pc, top_ptr, envt);