2 files changed, 169 insertions, 0 deletions
diff --git a/src/scope.c b/src/scope.c
new file mode 100644
index 0000000..de1295e
--- /dev/null
+++ b/src/scope.c
@@ -0,0 +1,123 @@
+/*
+ * Copyright (C) 2023 Carlos Maniero
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+#include "scope.h"
+#include <errno.h>
+#include <stdio.h>
+#include <string.h>
+
+static scope_item_t *
+scope_item_new()
+{
+  scope_item_t *item = malloc(sizeof(scope_item_t));
+  if (item == NULL) {
+    fprintf(stderr, "failed to create scope item: %s\n", strerror(errno));
+    exit(EXIT_FAILURE);
+  }
+  return item;
+}
+
+static void
+scope_item_destroy(scope_item_t *item)
+{
+  free(item);
+}
+
+scope_t *
+scope_new()
+{
+  scope_t *scope = malloc(sizeof(scope_t));
+
+  if (scope == NULL) {
+    fprintf(stderr, "failed to create scope: %s\n", strerror(errno));
+    exit(EXIT_FAILURE);
+  }
+
+  scope->stack = vector_new();
+  scope_enter(scope);
+  return scope;
+}
+
+void
+scope_destroy(scope_t *scope)
+{
+  if (scope->stack->size) {
+    fprintf(stderr,
+            "Stack not cleaned before destroying. This may lead to memory leaks.\n"
+            "Please make sure to call the leave function before destroying it.");
+  }
+
+  for (size_t i = 0; i < scope->stack->size; i++) {
+    vector_destroy(vector_at(scope->stack, i));
+  }
+
+  vector_destroy(scope->stack);
+  free(scope);
+}
+
+void
+scope_enter(scope_t *scope)
+{
+  vector_push_back(scope->stack, vector_new());
+}
+
+void
+scope_leave(scope_t *scope)
+{
+  // FIXME: create a stack data structure to simplify this logic
+  vector_t *new_stack = vector_new();
+
+  for (size_t i = 0; i < scope->stack->size - 1; i++) {
+    vector_push_back(new_stack, vector_at(scope->stack, i));
+  }
+
+  vector_t *current_level = vector_at(scope->stack, scope->stack->size - 1);
+
+  for (size_t i = 0; i < current_level->size; i++) {
+    scope_item_destroy(vector_at(current_level, i));
+  }
+
+  vector_destroy(current_level);
+  vector_t *old_stack = scope->stack;
+  vector_destroy(old_stack);
+  scope->stack = new_stack;
+}
+
+ast_node_t *
+scope_get(scope_t *scope, ast_identifier_t *identifier)
+{
+  for (size_t i = scope->stack->size; i > 0; i--) {
+    vector_t *current_level = vector_at(scope->stack, i - 1);
+
+    for (size_t j = 0; j < current_level->size; j++) {
+      scope_item_t *item = vector_at(current_level, j);
+
+      if (string_view_eq(identifier->name, item->identifier->name)) {
+        return item->node;
+      }
+    }
+  }
+
+  return NULL;
+}
+void
+scope_push(scope_t *scope, ast_identifier_t *identifier, ast_node_t *node)
+{
+  vector_t *current_level = vector_at(scope->stack, scope->stack->size - 1);
+  scope_item_t *item = scope_item_new();
+  *item = (scope_item_t){ .identifier = identifier, .node = node };
+  vector_push_back(current_level, item);
+}
diff --git a/src/scope.h b/src/scope.h
new file mode 100644
index 0000000..bce3567
--- /dev/null
+++ b/src/scope.h
@@ -0,0 +1,46 @@
+/*
+ * Copyright (C) 2023 Carlos Maniero
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+#include "ast.h"
+#include "string_view.h"
+#include "vector.h"
+
+typedef struct scope_t
+{
+  vector_t *stack;
+} scope_t;
+
+typedef struct scope_item_t
+{
+  ast_identifier_t *identifier;
+  ast_node_t *node;
+} scope_item_t;
+
+scope_t *
+scope_new();
+
+void
+scope_destroy(scope_t *scope);
+
+void
+scope_enter(scope_t *scope);
+void
+scope_leave(scope_t *scope);
+
+ast_node_t *
+scope_get(scope_t *scope, ast_identifier_t *identifier);
+void
+scope_push(scope_t *scope, ast_identifier_t *identifier, ast_node_t *node);