Big refactorHEADmaster

7 files changed, 570 insertions, 0 deletions

diff --git a/src/runtime/value/array.c b/src/runtime/value/array.c
new file mode 100644
index 0000000..1af84fd
--- /dev/null
+++ b/src/runtime/value/array.c
@@ -0,0 +1,57 @@
+#include <lcq/pit/runtime/value/array.h>
+
+bool pit_value_is_array(pit_runtime *rt, pit_value a) {
+    return pit_value_is_ref_heavy_sort(rt, a, PIT_VALUE_HEAVY_SORT_ARRAY);
+}
+
+pit_value pit_value_array_new(pit_runtime *rt, i64 len) {
+    if (len < 0) { pit_error(rt, "failed to create array of negative size"); return PIT_NIL; }
+    i64 byte_len = 0; pit_mul(&byte_len, sizeof(pit_value), len);
+    pit_value *dest = pit_arena_alloc_array(rt->heap, byte_len);
+    if (!dest) { pit_error(rt, "failed to allocate array"); return PIT_NIL; }
+    for (i64 i = 0; i < len; ++i) dest[i] = PIT_NIL;
+    pit_value ret = pit_value_ref_heavy_new(rt);
+    pit_value_heavy *h = pit_value_ref_deref(rt, pit_value_as_ref(rt, ret));
+    if (!h) { pit_error(rt, "failed to create new heavy value for array"); return PIT_NIL; }
+    h->hsort = PIT_VALUE_HEAVY_SORT_ARRAY;
+    h->in.array.data = dest;
+    h->in.array.len = len;
+    return ret;
+}
+pit_value pit_value_array_from_buf(pit_runtime *rt, pit_value *xs, i64 len) {
+    pit_value ret = pit_value_array_new(rt, len);
+    pit_value_heavy *h = pit_value_ref_deref(rt, pit_value_as_ref(rt, ret));
+    if (!h) { pit_error(rt, "failed to deref heavy value for array"); return PIT_NIL; }
+    pit_libc_string_memcpy((u8 *) h->in.array.data, (u8 *) xs, (size_t) len * (size_t) sizeof(pit_value));
+    return ret;
+}
+i64 pit_value_array_len(pit_runtime *rt, pit_value arr) {
+    if (pit_value_sort(arr) != PIT_VALUE_SORT_REF) { pit_error(rt, "not a ref"); return -1; }
+    pit_value_heavy *h = pit_value_ref_deref(rt, pit_value_as_ref(rt, arr));
+    if (!h) { pit_error(rt, "bad ref"); return -1; }
+    if (h->hsort != PIT_VALUE_HEAVY_SORT_ARRAY) { pit_error(rt, "not an array"); return -1; }
+    return h->in.array.len;
+}
+pit_value pit_value_array_get(pit_runtime *rt, pit_value arr, i64 idx) {
+    if (pit_value_sort(arr) != PIT_VALUE_SORT_REF) { pit_error(rt, "not a ref"); return PIT_NIL; }
+    pit_value_heavy *h = pit_value_ref_deref(rt, pit_value_as_ref(rt, arr));
+    if (!h) { pit_error(rt, "bad ref"); return PIT_NIL; }
+    if (h->hsort != PIT_VALUE_HEAVY_SORT_ARRAY) { pit_error(rt, "not an array"); return PIT_NIL; }
+    if (idx < 0 || idx >= h->in.array.len) {
+        pit_error(rt, "array index out of bounds: %d", idx);
+        return PIT_NIL;
+    }
+    return h->in.array.data[idx];
+}
+pit_value pit_value_array_set(pit_runtime *rt, pit_value arr, i64 idx, pit_value v) {
+    if (pit_value_sort(arr) != PIT_VALUE_SORT_REF) { pit_error(rt, "not a ref"); return PIT_NIL; }
+    pit_value_heavy *h = pit_value_ref_deref(rt, pit_value_as_ref(rt, arr));
+    if (!h) { pit_error(rt, "bad ref"); return PIT_NIL; }
+    if (h->hsort != PIT_VALUE_HEAVY_SORT_ARRAY) { pit_error(rt, "not an array"); return PIT_NIL; }
+    if (idx < 0 || idx >= h->in.array.len) {
+        pit_error(rt, "array index out of bounds: %d", idx);
+        return PIT_NIL;
+    }
+    h->in.array.data[idx] = v;
+    return v;
+}
diff --git a/src/runtime/value/bytes.c b/src/runtime/value/bytes.c
new file mode 100644
index 0000000..6a6edb6
--- /dev/null
+++ b/src/runtime/value/bytes.c
@@ -0,0 +1,47 @@
+#include <lcq/pit/runtime/value/bytes.h>
+
+bool pit_value_is_bytes(pit_runtime *rt, pit_value a) {
+    return pit_value_is_ref_heavy_sort(rt, a, PIT_VALUE_HEAVY_SORT_BYTES);
+}
+pit_value pit_value_bytes_new(pit_runtime *rt, u8 *buf, i64 len) {
+    u8 *dest = pit_arena_alloc_back(rt->heap, len);
+    if (!dest) { pit_error(rt, "failed to allocate bytes"); return PIT_NIL; }
+    pit_libc_string_memcpy(dest, buf, (size_t) len);
+    pit_value ret = pit_value_ref_heavy_new(rt);
+    pit_value_heavy *h = pit_value_ref_deref(rt, pit_value_as_ref(rt, ret));
+    if (!h) { pit_error(rt, "failed to create new heavy value for bytes"); return PIT_NIL; }
+    h->hsort = PIT_VALUE_HEAVY_SORT_BYTES;
+    h->in.bytes.data = dest;
+    h->in.bytes.len = len;
+    return ret;
+}
+pit_value pit_value_bytes_new_cstr(pit_runtime *rt, char *s) {
+    return pit_value_bytes_new(rt, (u8 *) s, (i64) pit_libc_string_strlen(s));
+}
+/* return true if v is a reference to bytes that are the same as those in buf */
+bool pit_value_bytes_match(pit_runtime *rt, pit_value v, u8 *buf, i64 len) {
+    if (pit_value_sort(v) != PIT_VALUE_SORT_REF) return false;
+    pit_value_heavy *h = pit_value_ref_deref(rt, pit_value_as_ref(rt, v));
+    if (!h) { pit_error(rt, "bad ref"); return false; }
+    if (h->hsort != PIT_VALUE_HEAVY_SORT_BYTES) return false;
+    if (h->in.bytes.len != len) return false;
+    for (i64 i = 0; i < len; ++i)
+        if (h->in.bytes.data[i] != buf[i]) {
+            return false;
+        }
+    return true;
+}
+i64 pit_value_bytes_copy(pit_runtime *rt, pit_value v, u8 *buf, i64 maxlen) {
+    if (pit_value_sort(v) != PIT_VALUE_SORT_REF) { pit_error(rt, "not a ref"); return -1; }
+    pit_value_heavy *h = pit_value_ref_deref(rt, pit_value_as_ref(rt, v));
+    if (!h) { pit_error(rt, "bad ref"); return -1; }
+    if (h->hsort != PIT_VALUE_HEAVY_SORT_BYTES) {
+        pit_error(rt, "invalid use of value as bytes");
+        return -1;
+    }
+    i64 len = maxlen < h->in.bytes.len ? maxlen : h->in.bytes.len;
+    for (i64 i = 0; i < len; ++i) {
+        buf[i] = h->in.bytes.data[i];
+    }
+    return len;
+}
diff --git a/src/runtime/value/cell.c b/src/runtime/value/cell.c
new file mode 100644
index 0000000..34b9226
--- /dev/null
+++ b/src/runtime/value/cell.c
@@ -0,0 +1,47 @@
+#include <lcq/pit/runtime/value/cell.h>
+
+bool pit_value_is_cell(pit_runtime *rt, pit_value a) {
+    return pit_value_is_ref_heavy_sort(rt, a, PIT_VALUE_HEAVY_SORT_CELL);
+}
+pit_value pit_value_cell_new(pit_runtime *rt, pit_value v) {
+    pit_value ret = pit_value_ref_heavy_new(rt);
+    pit_value_heavy *h = pit_value_ref_deref(rt, pit_value_as_ref(rt, ret));
+    if (!h) { pit_error(rt, "failed to create new heavy value for cell"); return PIT_NIL; }
+    h->hsort = PIT_VALUE_HEAVY_SORT_CELL;
+    h->in.cell = v;
+    return ret;
+}
+pit_value pit_value_cell_get(pit_runtime *rt, pit_value cell, pit_value sym) {
+    if (pit_value_sort(cell) != PIT_VALUE_SORT_REF) {
+        char buf[256];
+        i64 end = pit_dump(rt, buf, sizeof(buf) - 1, sym, false);
+        buf[end] = 0;
+        pit_error(rt, "attempted to get unbound variable/function: %s", buf);
+        return PIT_NIL;
+    }
+    pit_value_heavy *h = pit_value_ref_deref(rt, pit_value_as_ref(rt, cell));
+    if (!h) { pit_error(rt, "bad ref"); return PIT_NIL; }
+    if (h->hsort != PIT_VALUE_HEAVY_SORT_CELL) {
+        pit_error(rt, "cell value ref does not point to cell");
+        return PIT_NIL;
+    }
+    return h->in.cell;
+}
+void pit_value_cell_set(pit_runtime *rt, pit_value cell, pit_value v, pit_value sym) {
+    if (pit_value_sort(cell) != PIT_VALUE_SORT_REF) {
+        char buf[256];
+        i64 end = pit_dump(rt, buf, sizeof(buf) - 1, sym, false);
+        buf[end] = 0;
+        pit_error(rt, "attempted to set unbound variable/function: %s", buf);
+        return;
+    }
+    pit_ref idx = pit_value_as_ref(rt, cell);
+    if (idx < rt->frozen_values) { pit_error(rt, "attempt to modify frozen cell"); return; }
+    pit_value_heavy *h = pit_value_ref_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");
+        return;
+    }
+    h->in.cell = v;
+}
diff --git a/src/runtime/value/cons.c b/src/runtime/value/cons.c
new file mode 100644
index 0000000..0f35631
--- /dev/null
+++ b/src/runtime/value/cons.c
@@ -0,0 +1,110 @@
+#include <lcq/pit/runtime/value/cons.h>
+
+bool pit_value_is_cons(pit_runtime *rt, pit_value a) {
+    return pit_value_is_ref_heavy_sort(rt, a, PIT_VALUE_HEAVY_SORT_CONS);
+}
+pit_value pit_value_cons(pit_runtime *rt, pit_value car, pit_value cdr) {
+    pit_value ret = pit_value_ref_heavy_new(rt);
+    pit_value_heavy *h = pit_value_ref_deref(rt, pit_value_as_ref(rt, ret));
+    if (!h) { pit_error(rt, "failed to create new heavy value for cons"); return PIT_NIL; }
+    h->hsort = PIT_VALUE_HEAVY_SORT_CONS;
+    h->in.cons.car = car;
+    h->in.cons.cdr = cdr;
+    return ret;
+}
+pit_value pit_value_cons_car(pit_runtime *rt, pit_value v) {
+    if (pit_value_sort(v) != PIT_VALUE_SORT_REF) return PIT_NIL;
+    pit_value_heavy *h = pit_value_ref_deref(rt, pit_value_as_ref(rt, v));
+    if (!h) { pit_error(rt, "bad ref"); return PIT_NIL; }
+    if (h->hsort != PIT_VALUE_HEAVY_SORT_CONS) return PIT_NIL;
+    return h->in.cons.car;
+}
+pit_value pit_value_cons_cdr(pit_runtime *rt, pit_value v) {
+    if (pit_value_sort(v) != PIT_VALUE_SORT_REF) return PIT_NIL;
+    pit_value_heavy *h = pit_value_ref_deref(rt, pit_value_as_ref(rt, v));
+    if (!h) { pit_error(rt, "bad ref"); return PIT_NIL; }
+    if (h->hsort != PIT_VALUE_HEAVY_SORT_CONS) return PIT_NIL;
+    return h->in.cons.cdr;
+}
+void pit_value_cons_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_ref idx = pit_value_as_ref(rt, v);
+    if (idx < rt->frozen_values) { pit_error(rt, "attempted to modify frozen cons"); return; }
+    pit_value_heavy *h = pit_value_ref_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->in.cons.car = x;
+}
+void pit_value_cons_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_ref idx = pit_value_as_ref(rt, v);
+    if (idx < rt->frozen_values) { pit_error(rt, "attempted to modify frozen cons"); return; }
+    pit_value_heavy *h = pit_value_ref_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->in.cons.cdr = x;
+}
+
+pit_value pit_value_list(pit_runtime *rt, i64 num, ...) {
+    pit_value temp[64] = {0};
+    pit_value ret = PIT_NIL;
+    if (num > 64) { pit_error(rt, "failed to create list of size %d\n", num); return PIT_NIL; }
+    va_list elems;
+    va_start(elems, num);
+    for (i64 i = 0; i < num; ++i) {
+        temp[i] = va_arg(elems, pit_value);
+    }
+    va_end(elems);
+    for (i64 i = 0; i < num; ++i) {
+        ret = pit_value_cons(rt, temp[num - i - 1], ret);
+    }
+    return ret;
+}
+i64 pit_value_list_len(pit_runtime *rt, pit_value xs) {
+    i64 ret = 0;
+    while (xs != PIT_NIL) {
+        ret += 1;
+        xs = pit_value_cons_cdr(rt, xs);
+    }
+    return ret;
+}
+pit_value pit_value_list_append(pit_runtime *rt, pit_value xs, pit_value ys) {
+    pit_value ret = ys;
+    xs = pit_value_list_reverse(rt, xs);
+    while (xs != PIT_NIL) {
+        ret = pit_value_cons(rt, pit_value_cons_car(rt, xs), ret);
+        xs = pit_value_cons_cdr(rt, xs);
+    }
+    return ret;
+}
+pit_value pit_value_list_reverse(pit_runtime *rt, pit_value xs) {
+    pit_value ret = PIT_NIL;
+    while (xs != PIT_NIL) {
+        ret = pit_value_cons(rt, pit_value_cons_car(rt, xs), ret);
+        xs = pit_value_cons_cdr(rt, xs);
+    }
+    return ret;
+}
+pit_value pit_value_list_contains_eq(pit_runtime *rt, pit_value needle, pit_value haystack) {
+    while (haystack != PIT_NIL) {
+        if (pit_value_eq(needle, pit_value_cons_car(rt, haystack))) return PIT_T;
+        haystack = pit_value_cons_cdr(rt, haystack);
+    }
+    return PIT_NIL;
+}
+pit_value pit_value_list_contains_equal(pit_runtime *rt, pit_value needle, pit_value haystack) {
+    while (haystack != PIT_NIL) {
+        if (pit_value_equal(rt, needle, pit_value_cons_car(rt, haystack))) return PIT_T;
+        haystack = pit_value_cons_cdr(rt, haystack);
+    }
+    return PIT_NIL;
+}
+pit_value pit_value_list_plist_get(pit_runtime *rt, pit_value k, pit_value vs) {
+    while (vs != PIT_NIL) {
+        if (pit_value_eq(k, pit_value_cons_car(rt, vs))) {
+            return pit_value_cons_car(rt, pit_value_cons_cdr(rt, vs));
+        }
+        vs = pit_value_cons_cdr(rt, vs);
+    }
+    return PIT_NIL;
+}
diff --git a/src/runtime/value/func.c b/src/runtime/value/func.c
new file mode 100644
index 0000000..af039eb
--- /dev/null
+++ b/src/runtime/value/func.c
@@ -0,0 +1,177 @@
+#include <lcq/pit/runtime/value/func.h>
+
+static pit_value free_vars(pit_runtime *rt, pit_value initial_bound, pit_value body) {
+    i64 expr_stack_reset = rt->expr_stack->next;
+    pit_value ret = PIT_NIL;
+    if (pit_vec_push(pit_value)(rt->expr_stack, pit_value_cons(rt, initial_bound, body)) < 0) {
+        pit_error(rt, "free variable search stack overflow");
+        return PIT_NIL;
+    }
+    while (rt->expr_stack->next > expr_stack_reset) {
+        pit_value boundscur, bound, cur;
+        if (pit_vec_pop(pit_value)(rt->expr_stack, &boundscur) < 0) {
+            pit_error(rt, "free variable search stack underflow");
+            return PIT_NIL;
+        }
+        bound = pit_value_cons_car(rt, boundscur);
+        cur = pit_value_cons_cdr(rt, boundscur);
+        if (pit_value_is_cons(rt, cur)) {
+            pit_value fsym = pit_value_cons_car(rt, cur);
+            bool is_symbol = pit_value_is_symbol(rt, fsym);
+            pit_value fargs = pit_value_cons_cdr(rt, cur);
+            if (is_symbol && pit_symtab_symbol_name_match_cstr(rt, fsym, "lambda")) {
+                pit_value new_bound = pit_value_list_append(rt, pit_value_cons_car(rt, fargs), bound);
+                fargs = pit_value_cons_cdr(rt, fargs);
+                while (fargs != PIT_NIL) {
+                    if (pit_vec_push(pit_value)(rt->expr_stack, pit_value_cons(rt, new_bound, pit_value_cons_car(rt, fargs))) < 0) {
+                        pit_error(rt, "free variable search stack overflow");
+                        return PIT_NIL;
+                    }
+                    fargs = pit_value_cons_cdr(rt, fargs);
+                }
+            } else if (is_symbol && pit_symtab_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 (fargs != PIT_NIL) {
+                    if (pit_vec_push(pit_value)(rt->expr_stack, pit_value_cons(rt, bound, pit_value_cons_car(rt, fargs))) < 0) {
+                        pit_error(rt, "free variable search stack overflow");
+                        return PIT_NIL;
+                    }
+                    fargs = pit_value_cons_cdr(rt, fargs);
+                }
+                if (!is_symbol) {
+                    if (pit_vec_push(pit_value)(rt->expr_stack, pit_value_cons(rt, bound, fsym)) < 0) {
+                        pit_error(rt, "free variable search stack overflow");
+                        return PIT_NIL;
+                    }
+                }
+            }
+        } else if (pit_value_is_symbol(rt, cur)) {
+            if (pit_value_list_contains_eq(rt, cur, bound) == PIT_NIL) {
+                ret = pit_value_cons(rt, cur, ret);
+            }
+        }
+    }
+    rt->expr_stack->next = expr_stack_reset;
+    return ret;
+}
+
+bool pit_value_is_func(pit_runtime *rt, pit_value a) {
+    return pit_value_is_ref_heavy_sort(rt, a, PIT_VALUE_HEAVY_SORT_FUNC);
+}
+bool pit_value_is_nativefunc(pit_runtime *rt, pit_value a) {
+    return pit_value_is_ref_heavy_sort(rt, a, PIT_VALUE_HEAVY_SORT_NATIVEFUNC);
+}
+pit_value pit_value_func_lambda(pit_runtime *rt, pit_value args, pit_value body) {
+    pit_value ret = pit_value_ref_heavy_new(rt);
+    pit_value_heavy *h = pit_value_ref_deref(rt, pit_value_as_ref(rt, ret));
+    if (!h) { pit_error(rt, "failed to create new heavy value for lambda"); return PIT_NIL; }
+    pit_value expanded = pit_macroexpand(rt, pit_value_cons(rt, pit_symtab_intern_cstr(rt, "progn"), body));
+    pit_value freevars = free_vars(rt, args, expanded);
+    pit_value env = PIT_NIL;
+    while (freevars != PIT_NIL) {
+        pit_value sym = pit_value_cons_car(rt, freevars);
+        pit_value cell = pit_symtab_get_value_cell(rt, sym);
+        env = pit_value_cons(rt, pit_value_cons(rt, sym, cell), env);
+        freevars = pit_value_cons_cdr(rt, freevars);
+    }
+    h->hsort = PIT_VALUE_HEAVY_SORT_FUNC;
+    pit_value arg_cells = PIT_NIL;
+    pit_value arg_rest_nm = PIT_NIL;
+    pit_value separator = pit_symtab_intern_cstr(rt, "&");
+    while (args != PIT_NIL) {
+        pit_value nm = pit_value_cons_car(rt, args);
+        if (pit_value_eq(nm, separator)) {
+            pit_value next_nm = pit_value_cons_car(rt, pit_value_cons_cdr(rt, args));
+            if (next_nm == PIT_NIL) { pit_error(rt, "invalid & in lambda list"); return PIT_NIL; }
+            arg_rest_nm = next_nm;
+            arg_cells = pit_value_cons(rt, next_nm, arg_cells);
+            break;
+        } else {
+            arg_cells = pit_value_cons(rt, nm, arg_cells);
+            args = pit_value_cons_cdr(rt, args);
+        }
+    }
+    arg_cells = pit_value_list_reverse(rt, arg_cells);
+    h->in.func.args = arg_cells;
+    h->in.func.arg_rest_nm = arg_rest_nm;
+    h->in.func.env = env;
+    h->in.func.body = expanded;
+    return ret;
+}
+pit_value pit_value_nativefunc_new_with_data(pit_runtime *rt, pit_nativefunc f, void *data) {
+    pit_value ret = pit_value_ref_heavy_new(rt);
+    pit_value_heavy *h = pit_value_ref_deref(rt, pit_value_as_ref(rt, ret));
+    if (!h) { pit_error(rt, "failed to create new heavy value for nativefunc"); return PIT_NIL; }
+    h->hsort = PIT_VALUE_HEAVY_SORT_NATIVEFUNC;
+    h->in.nativefunc.f = f;
+    h->in.nativefunc.data = data;
+    return ret;
+}
+pit_value pit_value_nativefunc_new(pit_runtime *rt, pit_nativefunc f) {
+    return pit_value_nativefunc_new_with_data(rt, f, NULL);
+}
+pit_value pit_value_apply(pit_runtime *rt, pit_value f, pit_value args) {
+    char buf[256] = {0};
+    if (pit_value_is_symbol(rt, f)) {
+        f = pit_symtab_fget(rt, f);
+    }
+    /* if f is not a symbol, assume it is a func or nativefunc
+       most commonly, this happens when you funcall a variable
+       with a function in the value cell, e.g. passing a lambda to a function */
+    switch (pit_value_sort(f)) {
+    case PIT_VALUE_SORT_REF: {
+        pit_value_heavy *h = pit_value_ref_deref(rt, pit_value_as_ref(rt, f));
+        if (!h) { pit_error(rt, "bad ref"); return PIT_NIL; }
+        if (h->hsort == PIT_VALUE_HEAVY_SORT_FUNC) {
+            /* calling a Lisp function is simple! */
+            pit_value bound = PIT_NIL;
+            pit_value env = h->in.func.env;
+            while (env != PIT_NIL) { /* first, bind all entries in the closure */
+                pit_value b = pit_value_cons_car(rt, env);
+                pit_value nm = pit_value_cons_car(rt, b);
+                pit_symtab_bind(rt, nm, pit_value_cons_cdr(rt, b));
+                bound = pit_value_cons(rt, nm, bound);
+                env = pit_value_cons_cdr(rt, env);
+            }
+            pit_value anames = h->in.func.args;
+            while (anames != PIT_NIL) { /* bind all argument names to their values */
+                pit_value nm = pit_value_cons_car(rt, anames);
+                pit_value cell = pit_value_cell_new(rt, PIT_NIL);
+                if (h->in.func.arg_rest_nm != PIT_NIL && pit_value_eq(nm, h->in.func.arg_rest_nm)) {
+                    pit_value_cell_set(rt, cell, args, nm);
+                    pit_symtab_bind(rt, nm, cell);
+                    break;
+                } else {
+                    pit_value_cell_set(rt, cell, pit_value_cons_car(rt, args), nm);
+                    pit_symtab_bind(rt, nm, cell);
+                }
+                bound = pit_value_cons(rt, nm, bound);
+                args = pit_value_cons_cdr(rt, args);
+                anames = pit_value_cons_cdr(rt, anames);
+            }
+            pit_value ret = pit_eval(rt, h->in.func.body); /* evaluate the body */
+            while (bound != PIT_NIL) { /* unbind everything we bound earlier, in reverse */
+                pit_symtab_unbind(rt, pit_value_cons_car(rt, bound));
+                bound = pit_value_cons_cdr(rt, bound);
+            }
+            return ret;
+        } else if (h->hsort == PIT_VALUE_HEAVY_SORT_NATIVEFUNC) {
+            /* calling native functions is even simpler */
+            return h->in.nativefunc.f(rt, args, h->in.nativefunc.data);
+        } else {
+            i64 end = pit_dump(rt, buf, sizeof(buf) - 1, f, true);
+            buf[end] = 0;
+            pit_error(rt, "attempted to apply non-function ref: %s", buf);
+            return PIT_NIL;
+        }
+    }
+    default: {
+        i64 end = pit_dump(rt, buf, sizeof(buf) - 1, f, true);
+        buf[end] = 0;
+        pit_error(rt, "attempted to apply non-function value: %s", buf);
+        return PIT_NIL;
+    }
+    }
+}
diff --git a/src/runtime/value/nativedata.c b/src/runtime/value/nativedata.c
new file mode 100644
index 0000000..5c6fe2b
--- /dev/null
+++ b/src/runtime/value/nativedata.c
@@ -0,0 +1,36 @@
+#include <lcq/pit/runtime/value/nativedata.h>
+
+bool pit_value_is_nativedata(pit_runtime *rt, pit_value a) {
+    return pit_value_is_ref_heavy_sort(rt, a, PIT_VALUE_HEAVY_SORT_NATIVEDATA);
+}
+pit_value pit_value_nativedata_new(pit_runtime *rt, pit_value tag, void *d) {
+    pit_value ret = pit_value_ref_heavy_new(rt);
+    pit_value_heavy *h = pit_value_ref_deref(rt, pit_value_as_ref(rt, ret));
+    if (!h) { pit_error(rt, "failed to create new heavy value for nativedata"); return PIT_NIL; }
+    h->hsort = PIT_VALUE_HEAVY_SORT_NATIVEDATA;
+    h->in.nativedata.tag = tag;
+    h->in.nativedata.data = d;
+    return ret;
+}
+void *pit_value_nativedata_get(pit_runtime *rt, pit_value tag, pit_value v) {
+    pit_value_heavy *h = NULL;
+    if (pit_value_sort(v) != PIT_VALUE_SORT_REF) {
+        pit_error(rt, "value was not a reference");
+        return NULL;
+    }
+    h = pit_value_ref_deref(rt, pit_value_as_ref(rt, v));
+    if (!h) { pit_error(rt, "bad ref"); return NULL; }
+    if (h->hsort != PIT_VALUE_HEAVY_SORT_NATIVEDATA) {
+        pit_error(rt, "invalid use of value as nativedata");
+        return NULL;
+    }
+    if (!pit_value_eq(h->in.nativedata.tag, tag)) {
+        pit_error(rt, "native value does not match tag");
+        return NULL;
+    }
+    if (!h->in.nativedata.data) {
+        pit_error(rt, "nativedata was already freed");
+        return NULL;
+    }
+    return h->in.nativedata.data;
+}
diff --git a/src/runtime/value/small.c b/src/runtime/value/small.c
new file mode 100644
index 0000000..f07e405
--- /dev/null
+++ b/src/runtime/value/small.c
@@ -0,0 +1,96 @@
+#include <lcq/pit/runtime/value/small.h>
+
+#ifndef PIT_NO_DOUBLE
+double pit_value_as_double(pit_runtime *rt, pit_value v) {
+    if (pit_value_sort(v) != PIT_VALUE_SORT_DOUBLE) {
+        pit_error(rt, "invalid use of value as double");
+        return 0.0;
+    }
+    union { double dval; u64 ival; } x;
+    x.ival = v;
+    return x.dval;
+}
+bool pit_value_is_double(pit_runtime *rt, pit_value a) {
+    (void) rt;
+    return pit_value_sort(a) == PIT_VALUE_SORT_DOUBLE;
+}
+pit_value pit_value_double_new(pit_runtime *rt, double d) {
+    union { double dval; u64 ival; } x;
+    x.dval = d;
+    return pit_value_new(rt, PIT_VALUE_SORT_DOUBLE, x.ival);
+}
+#endif
+
+i64 pit_value_as_integer(pit_runtime *rt, pit_value v) {
+    if (pit_value_sort(v) != PIT_VALUE_SORT_INTEGER) {
+        pit_error(rt, "invalid use of value as integer");
+        return -1;
+    }
+    u64 lo = pit_value_data(v);
+    return ((i64) (lo << 15)) >> 15; /* sign-extend low 49 bits */
+
+}
+bool pit_value_is_integer(pit_runtime *rt, pit_value a) {
+    (void) rt;
+    return pit_value_sort(a) == PIT_VALUE_SORT_INTEGER;
+}
+pit_value pit_value_integer_new(pit_runtime *rt, i64 i) {
+    return pit_value_new(rt, PIT_VALUE_SORT_INTEGER, 0x1ffffffffffff & (u64) i);
+}
+pit_value pit_value_bool_new(pit_runtime *rt, bool i) {
+    (void) rt;
+    return i ? PIT_T : PIT_NIL;
+}
+
+pit_symbol pit_value_as_symbol(pit_runtime *rt, pit_value v) {
+    if (pit_value_sort(v) != PIT_VALUE_SORT_SYMBOL) {
+        pit_error(rt, "invalid use of value as symbol");
+        return -1;
+    }
+    return (pit_symbol) (pit_value_data(v) & 0xffffffff);
+}
+bool pit_value_is_symbol(pit_runtime *rt, pit_value a) {
+    (void) rt;
+    return pit_value_sort(a) == PIT_VALUE_SORT_SYMBOL;
+}
+pit_value pit_value_symbol_new(pit_runtime *rt, pit_symbol s) {
+    return pit_value_new(rt, PIT_VALUE_SORT_SYMBOL, (u64) s);
+}
+
+pit_ref pit_value_as_ref(pit_runtime *rt, pit_value v) {
+    if (pit_value_sort(v) != PIT_VALUE_SORT_REF) {
+        pit_error(rt, "invalid use of value as ref");
+        return -1;
+    }
+    return (pit_ref) (pit_value_data(v) & 0xffffffff);
+}
+bool pit_value_is_ref(pit_runtime *rt, pit_value a) {
+    (void) rt;
+    return pit_value_sort(a) == PIT_VALUE_SORT_REF;
+}
+pit_value pit_value_ref_new(pit_runtime *rt, pit_ref r) {
+    return pit_value_new(rt, PIT_VALUE_SORT_REF, (u64) r);
+}
+pit_value pit_value_ref_heavy_new(pit_runtime *rt) {
+    pit_arena_index idx = pit_arena_alloc_index(rt->heap);
+    if (idx < 0) {
+        pit_error(rt, "failed to allocate space for heavy value");
+        return PIT_NIL;
+    }
+    return pit_value_ref_new(rt, idx);
+}
+pit_value_heavy *pit_value_ref_deref(pit_runtime *rt, pit_ref p) {
+    return pit_arena_get(rt->heap, p);
+}
+bool pit_value_is_ref_heavy_sort(pit_runtime *rt, pit_value a, enum pit_value_heavy_sort e) {
+    switch (pit_value_sort(a)) {
+    case PIT_VALUE_SORT_REF: {
+        pit_value_heavy *ha = pit_value_ref_deref(rt, pit_value_as_ref(rt, a));
+        if (!ha) { pit_error(rt, "bad ref"); return false; }
+        return ha->hsort == e;
+    }
+    default:
+        break;
+    }
+    return false;
+}