1 files changed, 451 insertions, 0 deletions

diff --git a/src/stem.c b/src/stem.c
new file mode 100644
index 0000000..f090940
--- /dev/null
+++ b/src/stem.c
@@ -0,0 +1,451 @@
+#include <ctype.h>
+#include <macros.h>
+#include <math.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stem.h>
+#include <string.h>
+
+array_t *STACK;
+array_t *EVAL_STACK;
+ht_t *WORD_TABLE;
+char *INBUF;
+parser_t *PARSER;
+
+ht_t *FLIT;
+ht_t *OBJ_TABLE;
+
+void func_free(void *f) {}
+
+array_t *init_array(size_t size) {
+  array_t *a = calloc(1, sizeof(array_t));
+  a->size = 0;
+  a->capacity = size;
+  a->items = calloc(a->capacity, sizeof(value_t *));
+  return a;
+}
+
+void array_append(array_t *a, value_t *v) {
+  if (a->size >= a->capacity - 2) {
+    a->capacity = a->capacity * 2;
+    a->items = realloc(a->items, a->capacity * sizeof(value_t *));
+  }
+  a->items[a->size] = v;
+  a->size++;
+}
+
+value_t *array_pop(array_t *a) {
+  if (a->size > 0) {
+    value_t *v = a->items[a->size - 1];
+    a->size--;
+    return v;
+  }
+  return NULL;
+}
+
+void array_extend(array_t *a, array_t *b) {
+  for (int i = 0; i < b->size; i++) {
+    array_append(a, b->items[i]);
+  }
+}
+
+void array_free(array_t *a) {
+  for (int i = 0; i < a->size; i++) {
+    value_free(a->items[i]);
+  }
+  free(a->items);
+  free(a);
+}
+
+array_t *array_copy(array_t *a) {
+  array_t *b = calloc(1, sizeof(array_t));
+  b->size = a->size;
+  b->capacity = a->capacity;
+  b->items = calloc(b->capacity, sizeof(value_t *));
+  for (int i = 0; i < a->size; i++) {
+    b->items[i] = value_copy(a->items[i]);
+  }
+  return b;
+}
+
+value_t *init_value(int type) {
+  value_t *v = calloc(1, sizeof(value_t));
+  v->type = type;
+  v->escaped = false;
+  return v;
+}
+
+value_t *value_copy(value_t *v) {
+  value_t *a = init_value(VINT);
+  a->type = v->type;
+  if (v->type == VINT || v->type == VFLOAT) {
+    a->int_float = v->int_float;
+  } else if (v->type == VSTR || v->type == VWORD) {
+    a->str_word = string_copy(v->str_word);
+    a->escaped = v->escaped;
+  } else if (v->type == VQUOTE) {
+    a->quote = array_copy(v->quote);
+  } else if (v->type == VCUSTOM) {
+    custom_t *c = ht_get(OBJ_TABLE, a->str_word);
+    a->custom = c->copyfunc(v->custom);
+    a->str_word = string_copy(v->str_word);
+  }
+  return a;
+}
+
+void value_free(void *vtmp) {
+  value_t *v = (value_t *)vtmp;
+  if (v->type == VSTR || v->type == VWORD) {
+    string_free(v->str_word);
+  }
+  if (v->type == VQUOTE) {
+    array_free(v->quote);
+  }
+  if (v->type == VCUSTOM) {
+    void (*freefunc)(void *) = ht_get(OBJ_TABLE, v->str_word);
+    freefunc(v->custom);
+  }
+  free(v);
+}
+
+custom_t *init_custom(void (*printfunc)(void *), void (*freefunc)(void *),
+                      void *(*copyfunc)(void *)) {
+  custom_t *c = calloc(1, sizeof(custom_t));
+  c->printfunc = printfunc;
+  c->freefunc = freefunc;
+  c->copyfunc = copyfunc;
+  return c;
+}
+
+void custom_free(void *c) { free(c); }
+
+parser_t *init_parser(char *source) {
+  parser_t *p = calloc(1, sizeof(parser_t));
+  p->i = 0;
+  p->source = source;
+  p->c = source[0];
+  return p;
+}
+
+void parser_reset(parser_t *p, char *source) {
+  p->source = source;
+  p->i = 0;
+  p->c = source[0];
+}
+
+void parser_move(parser_t *p) {
+  if (p->i < strlen(p->source) && p->c != '\0') {
+    p->i++;
+    p->c = p->source[p->i];
+  }
+}
+
+void parser_skip_whitespace(parser_t *p) {
+  while (isspace(p->c)) {
+    parser_move(p);
+  }
+}
+
+value_t *parse_string(parser_t *p) {
+  value_t *retv = init_value(VSTR);
+  parser_move(p);
+  string_t *s = init_string(NULL);
+  bool escaped = false;
+  while (escaped || p->c != '"' && p->c != '\0') {
+    if (p->c == '\\') {
+      escaped = true;
+      parser_move(p);
+      continue;
+    }
+    if (escaped) {
+      switch (p->c) {
+      case '"':
+        string_append(s, '"');
+        break;
+      case 'n':
+        string_append(s, '\n');
+        break;
+      case 'r':
+        string_append(s, '\r');
+        break;
+      case 't':
+        string_append(s, '\t');
+        break;
+      case '\\':
+        string_append(s, '\\');
+        break;
+      default:
+        string_append(s, p->c);
+        break;
+      }
+      parser_move(p);
+      escaped = false;
+    } else {
+      string_append(s, p->c);
+      parser_move(p);
+      escaped = false;
+    }
+  }
+  parser_move(p);
+  retv->str_word = s;
+  return retv;
+}
+
+value_t *parse_quote(parser_t *p) {
+  value_t *retv = init_value(VQUOTE);
+  retv->quote = init_array(10);
+  parser_move(p);
+  parser_skip_whitespace(p);
+  while (p->c != ']') {
+    array_append(retv->quote, parser_get_next(p));
+    parser_skip_whitespace(p);
+  }
+  parser_move(p);
+  return retv;
+}
+
+void parser_error(parser_t *p) { exit(1); }
+
+value_t *parse_word(parser_t *p) {
+  value_t *retv = init_value(VWORD);
+  string_t *s = init_string(NULL);
+  if (p->c == '\\') {
+    retv->escaped = true;
+    parser_move(p);
+    if (isspace(p->c) || p->c == '\0') {
+      parser_error(p);
+    }
+  }
+  while (!isspace(p->c) && p->c != '\0') {
+    string_append(s, p->c);
+    parser_move(p);
+  }
+  retv->str_word = s;
+  return retv;
+}
+
+value_t *parse_num(parser_t *p) {
+  value_t *retv;
+  string_t *s = init_string(NULL);
+  bool is_float = false;
+  while (isdigit(p->c) || (p->c == '.') && !is_float) {
+    if (p->c == '.')
+      is_float = true;
+    string_append(s, p->c);
+    parser_move(p);
+  }
+  if (is_float)
+    retv = init_value(VFLOAT);
+  else
+    retv = init_value(VINT);
+  retv->int_float = atof(s->value);
+  string_free(s);
+  return retv;
+}
+
+value_t *parser_get_next(parser_t *p) {
+  parser_skip_whitespace(p);
+  if (isdigit(p->c)) {
+    return parse_num(p);
+  }
+  switch (p->c) {
+  case '"':
+    return parse_string(p);
+  case '[':
+    return parse_quote(p);
+  case '\0':
+    return NULL;
+  default:
+    return parse_word(p);
+  }
+}
+
+node_t *init_node(string_t *key, void *value) {
+  node_t *n = calloc(1, sizeof(node_t));
+  n->key = key;
+  n->value = value;
+  n->next = NULL;
+  return n;
+}
+
+void node_free(node_t *n, void (*freefunc)(void *)) {
+  string_free(n->key);
+  freefunc(n->value);
+  free(n);
+}
+
+sll_t *init_sll() {
+  sll_t *l = calloc(1, sizeof(sll_t));
+  l->size = 0;
+  l->head = NULL;
+  return l;
+}
+
+void sll_add(sll_t *l, string_t *s, void *v) {
+  if (l->head == NULL) {
+    node_t *n = init_node(s, v);
+    l->head = n;
+    l->size++;
+    return;
+  }
+  node_t *cur = l->head;
+  while (cur->next != NULL) {
+    if (strcmp(s->value, cur->key->value) == 0) {
+      value_free(cur->value);
+      string_free(s);
+      cur->value = v;
+      return;
+    }
+    cur = cur->next;
+  }
+  if (strcmp(s->value, cur->key->value) == 0) {
+    value_free(cur->value);
+    string_free(s);
+    cur->value = v;
+    return;
+  }
+  node_t *n = init_node(s, v);
+  cur->next = n;
+}
+
+void sll_add_func(sll_t *l, string_t *s, void *v) {
+  if (l->head == NULL) {
+    node_t *n = init_node(s, v);
+    l->head = n;
+    l->size++;
+    return;
+  }
+  node_t *cur = l->head;
+  while (cur->next != NULL) {
+    if (strcmp(s->value, cur->key->value) == 0) {
+      string_free(s);
+      cur->value = v;
+      return;
+    }
+    cur = cur->next;
+  }
+  if (strcmp(s->value, cur->key->value) == 0) {
+    string_free(s);
+    cur->value = v;
+    return;
+  }
+  node_t *n = init_node(s, v);
+  cur->next = n;
+}
+
+void *sll_get(sll_t *l, string_t *k) {
+  if (l->head == NULL)
+    return NULL;
+  node_t *cur = l->head;
+  while (cur != NULL) {
+    if (strcmp(k->value, cur->key->value) == 0)
+      return cur->value;
+    cur = cur->next;
+  }
+  return NULL;
+}
+
+void sll_free(sll_t *l, void (*func)(void *)) {
+  node_t *cur = l->head;
+  node_t *tmp;
+  while (cur != NULL) {
+    tmp = cur;
+    cur = cur->next;
+    node_free(tmp, func);
+  }
+  free(l);
+}
+
+ht_t *init_ht(size_t size) {
+  ht_t *h = calloc(1, sizeof(ht_t));
+  h->size = size;
+  h->buckets = calloc(h->size, sizeof(sll_t *));
+  for (int i = 0; i < size; i++) {
+    h->buckets[i] = init_sll();
+  }
+  return h;
+}
+
+void ht_add(ht_t *h, string_t *key, void *v) {
+  sll_add(h->buckets[hash(h, key->value)], key, v);
+}
+
+void ht_add_func(ht_t *h, string_t *key, void *v) {
+  sll_add_func(h->buckets[hash(h, key->value)], key, v);
+}
+
+void *ht_get(ht_t *h, string_t *key) {
+  return sll_get(h->buckets[hash(h, key->value)], key);
+}
+
+bool ht_exists(ht_t *h, string_t *key) { return ht_get(h, key) != NULL; }
+
+void ht_free(ht_t *h, void (*func)(void *)) {
+  for (int i = 0; i < h->size; i++) {
+    sll_free(h->buckets[i], func);
+  }
+  free(h->buckets);
+  free(h);
+}
+
+/* DJB2 HASH FUNCTION */
+unsigned long hash(ht_t *h, char *key) {
+  unsigned long hash = 5381;
+  int c;
+
+  while ((c = *key++))
+    hash = ((hash << 5) + hash) + c; /* hash * 33 + c */
+
+  return hash % h->size;
+}
+
+bool eval_ht(value_t *v) {
+  value_t *func = ht_get(WORD_TABLE, v->str_word);
+  if (func == NULL)
+    return false;
+  value_free(v);
+  if (func->type == VQUOTE) {
+    for (int i = 0; i < func->quote->size; i++) {
+      eval(value_copy(func->quote->items[i]));
+    }
+  } else {
+    eval(value_copy(func));
+  }
+  return true;
+}
+
+bool eval_builtins(value_t *v) {
+  void (*func)(value_t *) = ht_get(FLIT, v->str_word);
+  if (func == NULL)
+    return false;
+  array_append(EVAL_STACK, v);
+  func(v);
+  array_pop(EVAL_STACK);
+  value_free(v);
+  return true;
+}
+
+void eval(value_t *v) {
+  switch (v->type) {
+  case VINT:
+  case VFLOAT:
+  case VSTR:
+  case VQUOTE:
+  case VERR:
+  case VCUSTOM:
+    array_append(STACK, v);
+    break;
+  case VWORD:
+    if (v->escaped) {
+      v->escaped = false;
+      array_append(STACK, v);
+    } else {
+      if (!eval_builtins(v)) {
+        if (!eval_ht(v)) {
+          array_append(STACK, v);
+        }
+      }
+    }
+  }
+}