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#include "consts.h"
#include "eval.h"
#include "builtin.h"
#include "exc.h"
#include "gc.h"
#include <cstdio>
static const int EVAL_STACK_SIZE = 262144;
extern Pair *empty_list;
/** The stack for evaluating expressions */
EvalObj *eval_stack[EVAL_STACK_SIZE];
/** Add all kinds of built-in facilities before the evaluation */
void Evaluator::add_builtin_routines() {
#define ADD_ENTRY(name, rout) \
do { \
SymObj *tmp = new SymObj(name); \
envt->add_binding(tmp, rout); \
delete tmp; \
} while (0)
#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_ENTRY("or", new SpecialOptOr());
ADD_ENTRY("apply", new SpecialOptApply());
ADD_ENTRY("delay", new SpecialOptDelay());
ADD_ENTRY("force", new SpecialOptForce());
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);
ADD_BUILTIN_PROC("string<?", string_lt);
ADD_BUILTIN_PROC("string<=?", string_le);
ADD_BUILTIN_PROC("string>?", string_gt);
ADD_BUILTIN_PROC("string>=?", string_ge);
ADD_BUILTIN_PROC("string=?", string_eq);
ADD_BUILTIN_PROC("make-vector", make_vector);
ADD_BUILTIN_PROC("vector-set!", vector_set);
ADD_BUILTIN_PROC("vector-ref", vector_ref);
ADD_BUILTIN_PROC("vector-length", vector_length);
ADD_BUILTIN_PROC("gc-status", gc_status);
ADD_BUILTIN_PROC("set-gc-resolve-threshold!", set_gc_resolve_threshold);
}
Evaluator::Evaluator() {
envt = new Environment(NULL); // Top-level Environment
gc.attach(envt);
add_builtin_routines();
}
/**
* Initiate the `next` pointer of an s-expression (a list)
*/
inline bool make_exec(Pair *ptr) {
if (ptr == empty_list) return true;
EvalObj *nptr;
for (;;)
if ((nptr = ptr->cdr)->is_pair_obj())
{
ptr->next = TO_PAIR(nptr);
ptr = ptr->next;
}
else break;
ptr->next = NULL;
return ptr->cdr == empty_list;
}
/**
* Push a new stack frame according to current pc
*/
inline void push(Pair * &pc, EvalObj ** &top_ptr,
Environment * &envt, Continuation * &cont) {
if (pc->car->is_simple_obj()) // Not an opt invocation
{
// Objectify the symbol
*top_ptr++ = gc.attach(envt->get_obj(pc->car));
pc = pc->next; // Move to the next instruction
}
else // Operational Invocation
{
if (pc->car == empty_list)
throw NormalError(SYN_ERR_EMPTY_COMB);
if (!cont->tail) // a normal invocation
{
gc.expose(cont);
cont = new Continuation(envt, pc, cont);
gc.attach(cont);
*top_ptr++ = gc.attach(cont);
}
else cont->tail = false; // tail recursion opt
if (!make_exec(TO_PAIR(pc->car)))
// not a valid an invocation
throw TokenError(pc->car->ext_repr(), RUN_ERR_WRONG_NUM_OF_ARGS);
// dive into the call
cont->prog = pc = TO_PAIR(pc->car);
// "pre-call" for some `SpecialObj`
envt->get_obj(pc->car)->prepare(pc);
}
}
/**
* The main routine for the evaluation
*/
EvalObj *Evaluator::run_expr(Pair *prog) {
EvalObj **top_ptr = eval_stack;
Pair *pc = prog;
Continuation *bcont = new Continuation(NULL, NULL, NULL), // dummy cont
*cont = bcont;
#ifdef GC_DEBUG
fprintf(stderr, "Start the evaluation...\n");
#endif
// attach current cont and the whole s-expression tree, so they will not be
// garbage-collected
gc.attach(cont);
gc.attach(prog);
// envt is this->envt
push(pc, top_ptr, envt, cont);
// (cont != bcont) Still need to evaluate at least one level of invocation
while (cont != bcont)
{
if (top_ptr == eval_stack + EVAL_STACK_SIZE)
throw TokenError("Evaluation", RUN_ERR_STACK_OVERFLOW);
if (pc)
push(pc, top_ptr, envt, cont);
else // All arguments are evaluated
{
Pair *args = empty_list;
while (*(--top_ptr) != cont)
{
EvalObj* obj = static_cast<EvalObj*>(*top_ptr);
gc.expose(obj);
// old args is auto attached due to the constructor of `Pair`
args = new Pair(obj, args);
}
// manually protect the head pointer
gc.attach(args);
if ((args->car)->is_opt_obj())
{
OptObj *opt = static_cast<OptObj*>(args->car);
pc = opt->call(args, envt, cont, top_ptr, cont->prog);
}
else
throw TokenError((args->car)->ext_repr(), SYN_ERR_CAN_NOT_APPLY);
// gc.collect(); THIS IS DEPRECATED BECAUSE IT'S NOT A SAFE POINT
// ANYMORE DUE TO THE TAIL RECURSION OPT
}
}
// remove the protection
gc.expose(prog);
gc.expose(cont);
// static_cast because the previous while condition
return static_cast<EvalObj*>(*(eval_stack));
}
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