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-rw-r--r--src/runtime.c86
1 files changed, 57 insertions, 29 deletions
diff --git a/src/runtime.c b/src/runtime.c
index 230b595..3bfd1d4 100644
--- a/src/runtime.c
+++ b/src/runtime.c
@@ -16,32 +16,31 @@ pit_arena *pit_arena_new(i64 capacity, i64 elem_size) {
a->next = 0;
return a;
}
-
-i32 pit_arena_alloc_idx(pit_arena *a) {
+i32 pit_arena_next_idx(pit_arena *a) {
i32 byte_idx; pit_mul(&byte_idx, a->elem_size, a->next);
+ return byte_idx;
+}
+i32 pit_arena_alloc_idx(pit_arena *a) {
+ i32 byte_idx = pit_arena_next_idx(a);
if (byte_idx >= a->capacity) { return -1; }
a->next += 1;
return byte_idx;
}
-
i32 pit_arena_alloc_bulk_idx(pit_arena *a, i64 num) {
- i32 byte_idx; pit_mul(&byte_idx, a->elem_size, a->next);
+ i32 byte_idx = pit_arena_next_idx(a);
i32 byte_len; pit_mul(&byte_len, a->elem_size, num);
if (byte_idx + byte_len > a->capacity) { return -1; }
a->next += num;
return byte_idx;
}
-
void *pit_arena_idx(pit_arena *a, i32 idx) {
if (idx < 0 || idx >= a->capacity) return NULL;
return &a->data[idx];
}
-
void *pit_arena_alloc(pit_arena *a) {
i32 byte_idx = pit_arena_alloc_idx(a);
return pit_arena_idx(a, byte_idx);
}
-
void *pit_arena_alloc_bulk(pit_arena *a, i64 num) {
i32 byte_idx = pit_arena_alloc_bulk_idx(a, num);
return pit_arena_idx(a, byte_idx);
@@ -73,14 +72,30 @@ pit_runtime *pit_runtime_new() {
ret->result_stack = pit_values_new(1024);
ret->program = pit_runtime_eval_program_new(64 * 1024);
ret->saved_bindings = pit_values_new(1024);
+ ret->frozen_values = 0;
+ ret->frozen_bytes = 0;
+ ret->frozen_symtab = 0;
ret->error = PIT_NIL;
- pit_intern_cstr(ret, "nil"); // nil must be the 0th symbol for PIT_NIL to work
+ pit_value nil = pit_intern_cstr(ret, "nil"); // nil must be the 0th symbol for PIT_NIL to work
+ pit_set(ret, nil, PIT_NIL);
pit_value truth = pit_intern_cstr(ret, "t");
pit_set(ret, truth, truth);
pit_install_library_essential(ret);
+ pit_runtime_freeze(ret);
return ret;
}
+void pit_runtime_freeze(pit_runtime *rt) {
+ rt->frozen_values = pit_arena_next_idx(rt->values);
+ rt->frozen_bytes = pit_arena_next_idx(rt->bytes);
+ rt->frozen_symtab = pit_arena_next_idx(rt->symtab);
+}
+void pit_runtime_reset(pit_runtime *rt) {
+ rt->values->next = rt->frozen_values;
+ rt->bytes->next = rt->frozen_bytes;
+ rt->symtab->next = rt->frozen_symtab;
+}
+
i64 pit_dump(pit_runtime *rt, char *buf, i64 len, pit_value v) {
pit_value_heavy *h = NULL;
if (len <= 0) return 0;
@@ -416,6 +431,8 @@ pit_value pit_get(pit_runtime *rt, pit_value sym) {
return pit_cell_get(rt, pit_get_value_cell(rt, sym));
}
void pit_set(pit_runtime *rt, pit_value sym, pit_value v) {
+ pit_symbol idx = pit_as_symbol(rt, sym);
+ if (idx < rt->frozen_symtab) { pit_error(rt, "attempted to modify frozen symbol"); return; }
pit_symtab_entry *ent = pit_symtab_lookup(rt, sym);
if (!ent) { pit_error(rt, "bad symbol"); return; }
if (pit_value_sort(ent->value) != PIT_VALUE_SORT_REF) {
@@ -427,6 +444,8 @@ pit_value pit_fget(pit_runtime *rt, pit_value sym) {
return pit_cell_get(rt, pit_get_function_cell(rt, sym));
}
void pit_fset(pit_runtime *rt, pit_value sym, pit_value v) {
+ pit_symbol idx = pit_as_symbol(rt, sym);
+ if (idx < rt->frozen_symtab) { pit_error(rt, "attempted to modify frozen symbol"); return; }
pit_symtab_entry *ent = pit_symtab_lookup(rt, sym);
if (!ent) { pit_error(rt, "bad symbol"); return; }
if (pit_value_sort(ent->function) != PIT_VALUE_SORT_REF) {
@@ -463,6 +482,7 @@ void pit_sfset(pit_runtime *rt, pit_value sym, pit_value v) {
pit_symbol_is_special_form(rt, sym);
}
void pit_bind(pit_runtime *rt, pit_value sym, pit_value cell) {
+ // although we cannot set frozen symbols, we can still bind them temporarily - no need to check
pit_symtab_entry *ent = pit_symtab_lookup(rt, sym);
if (!ent) { pit_error(rt, "bad symbol"); return; }
pit_values_push(rt, rt->saved_bindings, ent->value);
@@ -502,7 +522,9 @@ void pit_cell_set(pit_runtime *rt, pit_value cell, pit_value v) {
pit_error(rt, "cell value is not ref");
return;
}
- pit_value_heavy *h = pit_deref(rt, pit_as_ref(rt, cell));
+ pit_ref idx = pit_as_ref(rt, cell);
+ if (idx < rt->frozen_values) { pit_error(rt, "attempt to modify frozen cell"); return; }
+ pit_value_heavy *h = pit_deref(rt, idx);
if (!h) { pit_error(rt, "bad ref"); return; }
if (h->hsort != PIT_VALUE_HEAVY_SORT_CELL) {
pit_error(rt, "cell value ref does not point to cell");
@@ -520,7 +542,6 @@ pit_value pit_cons(pit_runtime *rt, pit_value car, pit_value cdr) {
h->cons.cdr = cdr;
return ret;
}
-
pit_value pit_list(pit_runtime *rt, i64 num, ...) {
pit_value temp[64];
if (num > 64) { pit_error(rt, "failed to create list of size %d\n", num); return PIT_NIL; }
@@ -536,7 +557,6 @@ pit_value pit_list(pit_runtime *rt, i64 num, ...) {
}
return ret;
}
-
pit_value pit_car(pit_runtime *rt, pit_value v) {
if (pit_value_sort(v) != PIT_VALUE_SORT_REF) return PIT_NIL;
pit_value_heavy *h = pit_deref(rt, pit_as_ref(rt, v));
@@ -553,14 +573,18 @@ pit_value pit_cdr(pit_runtime *rt, pit_value v) {
}
void pit_setcar(pit_runtime *rt, pit_value v, pit_value x) {
if (pit_value_sort(v) != PIT_VALUE_SORT_REF) { pit_error(rt, "not a ref"); return; }
- pit_value_heavy *h = pit_deref(rt, pit_as_ref(rt, v));
+ pit_ref idx = pit_as_ref(rt, v);
+ if (idx < rt->frozen_values) { pit_error(rt, "attempted to modify frozen cons"); return; }
+ pit_value_heavy *h = pit_deref(rt, idx);
if (!h) { pit_error(rt, "bad ref"); return; }
if (h->hsort != PIT_VALUE_HEAVY_SORT_CONS) { pit_error(rt, "not a cons"); return; }
h->cons.car = x;
}
void pit_setcdr(pit_runtime *rt, pit_value v, pit_value x) {
if (pit_value_sort(v) != PIT_VALUE_SORT_REF) { pit_error(rt, "not a ref"); return; }
- pit_value_heavy *h = pit_deref(rt, pit_as_ref(rt, v));
+ pit_ref idx = pit_as_ref(rt, v);
+ if (idx < rt->frozen_values) { pit_error(rt, "attempted to modify frozen cons"); return; }
+ pit_value_heavy *h = pit_deref(rt, idx);
if (!h) { pit_error(rt, "bad ref"); return; }
if (h->hsort != PIT_VALUE_HEAVY_SORT_CONS) { pit_error(rt, "not a cons"); return; }
h->cons.cdr = x;
@@ -604,6 +628,8 @@ pit_value pit_free_vars(pit_runtime *rt, pit_value args, pit_value body) {
if (is_symbol && pit_symbol_name_match_cstr(rt, fsym, "lambda")) {
bound = pit_append(rt, pit_car(rt, args), bound);
} else if (is_symbol && pit_symbol_name_match_cstr(rt, fsym, "quote")) {
+ // don't look inside quote!
+ // if we add other special forms, make sure to consider them here if necessary!
} else {
while (args != PIT_NIL) {
pit_values_push(rt, rt->expr_stack, pit_car(rt, args));
@@ -622,7 +648,6 @@ pit_value pit_free_vars(pit_runtime *rt, pit_value args, pit_value body) {
rt->expr_stack->top = expr_stack_reset;
return ret;
}
-
pit_value pit_lambda(pit_runtime *rt, pit_value args, pit_value body) {
pit_value ret = pit_heavy_new(rt);
pit_value_heavy *h = pit_deref(rt, ret);
@@ -637,12 +662,19 @@ pit_value pit_lambda(pit_runtime *rt, pit_value args, pit_value body) {
freevars = pit_cdr(rt, freevars);
}
h->hsort = PIT_VALUE_HEAVY_SORT_FUNC;
- h->func.args = args;
+ pit_value arg_cells = PIT_NIL;
+ while (args != PIT_NIL) {
+ pit_value nm = pit_car(rt, args);
+ pit_value ent = pit_cons(rt, nm, pit_cell_new(rt, PIT_NIL));
+ arg_cells = pit_cons(rt, ent, arg_cells);
+ args = pit_cdr(rt, args);
+ }
+ arg_cells = pit_reverse(rt, arg_cells);
+ h->func.args = arg_cells;
h->func.env = env;
h->func.body = expanded;
return ret;
}
-
pit_value pit_nativefunc_new(pit_runtime *rt, pit_nativefunc f) {
pit_value ret = pit_heavy_new(rt);
pit_value_heavy *h = pit_deref(rt, ret);
@@ -651,7 +683,6 @@ pit_value pit_nativefunc_new(pit_runtime *rt, pit_nativefunc f) {
h->nativefunc = f;
return ret;
}
-
pit_value pit_apply(pit_runtime *rt, pit_value f, pit_value args) {
switch (pit_value_sort(f)) {
case PIT_VALUE_SORT_REF:
@@ -669,22 +700,15 @@ pit_value pit_apply(pit_runtime *rt, pit_value f, pit_value args) {
}
pit_value anames = h->func.args;
while (anames != PIT_NIL) {
- pit_value nm = pit_car(rt, anames);
- pit_value c = pit_cell_new(rt, pit_car(rt, args));
- pit_bind(rt, nm, c);
+ pit_value aform = pit_car(rt, anames);
+ pit_value nm = pit_car(rt, aform);
+ pit_value cell = pit_cdr(rt, aform);
+ pit_cell_set(rt, cell, pit_car(rt, args));
+ pit_bind(rt, nm, cell);
bound = pit_cons(rt, nm, bound);
args = pit_cdr(rt, args);
anames = pit_cdr(rt, anames);
}
- // update the closure's environment with new values
- env = h->func.env;
- while (env != PIT_NIL) {
- pit_value b = pit_car(rt, env);
- pit_value nm = pit_car(rt, b);
- pit_value v = pit_get(rt, nm);
- pit_cell_set(rt, pit_cdr(rt, b), v);
- env = pit_cdr(rt, env);
- }
pit_value ret = pit_eval(rt, h->func.body);
while (bound != PIT_NIL) {
pit_unbind(rt, pit_car(rt, bound));
@@ -739,6 +763,7 @@ pit_value pit_expand_macros(pit_runtime *rt, pit_value top) {
i64 program_reset = rt->program->top;
pit_values_push(rt, rt->expr_stack, top);
while (rt->expr_stack->top > 0) {
+ if (rt->error != PIT_NIL) goto end;
pit_value cur = pit_values_pop(rt, rt->expr_stack);
if (pit_is_cons(rt, cur)) {
pit_value fsym = pit_car(rt, cur);
@@ -810,6 +835,7 @@ pit_value pit_expand_macros(pit_runtime *rt, pit_value top) {
}
}
for (i64 idx = rt->program->top - 1; idx >= program_reset; --idx) {
+ if (rt->error != PIT_NIL) goto end;
pit_runtime_eval_program_entry *ent = &rt->program->data[idx];
switch (ent->sort) {
case EVAL_PROGRAM_ENTRY_LITERAL:
@@ -843,6 +869,7 @@ pit_value pit_eval(pit_runtime *rt, pit_value top) {
pit_values_push(rt, rt->expr_stack, top);
// first, convert the expression tree into "polish notation" in program
while (rt->expr_stack->top > 0) {
+ if (rt->error != PIT_NIL) goto end;
pit_value cur = pit_values_pop(rt, rt->expr_stack);
if (pit_is_cons(rt, cur)) { // compound expressions: function/macro application special forms
pit_value fsym = pit_car(rt, cur);
@@ -896,6 +923,7 @@ pit_value pit_eval(pit_runtime *rt, pit_value top) {
// then, execute the polish notation program from right to left
// this has the nice consequence of putting the arguments in the right order
for (i64 idx = rt->program->top - 1; idx >= program_reset; --idx) {
+ if (rt->error != PIT_NIL) goto end;
pit_runtime_eval_program_entry *ent = &rt->program->data[idx];
switch (ent->sort) {
case EVAL_PROGRAM_ENTRY_LITERAL:
generated by cgit v1.2.3 (git 2.25.1) at 2026-05-09 08:09:11 +0000