From ef0cbf240782010a4b71d32546e022dfd4f0b6bf Mon Sep 17 00:00:00 2001
From: Bad Diode <bd@badd10de.dev>
Date: Sun, 31 Oct 2021 14:25:44 +0100
Subject: Add number of arguments check in function calls

---
 src/parser.c | 83 +++++++++++++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 71 insertions(+), 12 deletions(-)

(limited to 'src/parser.c')

diff --git a/src/parser.c b/src/parser.c
index 59e8075..d4deb74 100644
--- a/src/parser.c
+++ b/src/parser.c
@@ -313,6 +313,7 @@ parse_list(Parser *parser, Errors *errors) {
     Object *root = object_alloc(start, OBJ_TYPE_PAIR);
     root->head = NULL;
     root->tail = NULL;
+    root->n_elems = 0;
     Object *current = root;
     bool first = true;
     while (has_next_token(parser)) {
@@ -346,6 +347,7 @@ parse_list(Parser *parser, Errors *errors) {
         next->tail = NULL;
         current->tail = next;
         current = current->tail;
+        root->n_elems++;
     }
     error_push(errors, (Error){
         .type = ERR_TYPE_PARSER,
@@ -404,16 +406,16 @@ parse_tree(Parser *parser, Errors *errors) {
     return NULL;
 }
 
-bool
+Object *
 symbol_in_env(Environment *env, Object *symbol) {
     while (env != NULL) {
         Object *found = ht_lookup(env->table, symbol);
         if (found != NULL) {
-            return true;
+            return found;
         }
         env = env->parent;
     }
-    return false;
+    return NULL;
 }
 
 void
@@ -423,7 +425,7 @@ check_object_scope(Environment *env, Object *obj, Errors *errors) {
     }
     switch (obj->type) {
         case OBJ_TYPE_SYMBOL: {
-            if (!symbol_in_env(env, obj)) {
+            if (symbol_in_env(env, obj) == NULL) {
                 error_push(errors, (Error){
                     .type = ERR_TYPE_PARSER,
                     .value = ERR_SYMBOL_NOT_FOUND,
@@ -505,6 +507,54 @@ remove_unused_expr(Object *obj) {
     }
 }
 
+void
+check_function_args(Environment *env, Object *obj, Errors *errors) {
+    if (obj == NULL || obj->visited) {
+        return;
+    }
+    obj->visited = true;
+    switch (obj->type) {
+        case OBJ_TYPE_SYMBOL: {
+            Object *found = symbol_in_env(env, obj);
+            check_function_args(env, found, errors);
+        } break;
+        case OBJ_TYPE_DEF:
+        case OBJ_TYPE_SET: {
+            check_function_args(env, obj->var_expr, errors);
+        } break;
+        case OBJ_TYPE_IF: {
+            check_function_args(env, obj->condition, errors);
+            check_function_args(env, obj->expr_true, errors);
+            check_function_args(env, obj->expr_false, errors);
+        } break;
+        case OBJ_TYPE_PAIR: {
+            Object *head = obj->head;
+            if (IS_SYMBOL(head)) {
+                head = symbol_in_env(env, head);
+            }
+            if (IS_LAMBDA(head)) {
+                if (obj->n_elems != array_size(head->params)) {
+                    error_push(errors, (Error){
+                        .type = ERR_TYPE_PARSER,
+                        .value = ERR_NOT_ENOUGH_ARGS,
+                        .line = obj->line,
+                        .col = obj->col
+                    });
+                }
+            }
+            check_function_args(env, head, errors);
+            check_function_args(env, obj->tail, errors);
+        } break;
+        case OBJ_TYPE_LAMBDA: {
+            for (size_t i = 0; i < array_size(obj->body); i++) {
+                Object *expr = obj->body[i];
+                check_function_args(obj->env, expr, errors);
+            }
+        } break;
+        default: break;
+    }
+}
+
 Root *
 parse(Token *tokens, Errors *errors) {
     array_init(roots, 0);
@@ -564,7 +614,6 @@ parse(Token *tokens, Errors *errors) {
             }
         }
         array_push(final_roots, root);
-
         remove_unused_expr(root);
         if (errors->n != 0) {
             return NULL;
@@ -573,6 +622,19 @@ parse(Token *tokens, Errors *errors) {
     array_free(roots);
     roots = final_roots;
 
+    // Check that the number of arguments in function calls match the number of
+    // formal parameters.
+    for (size_t i = 0; i < array_size(roots); i++) {
+        Object *root = roots[i];
+        check_function_args(global_env, root, errors);
+        if (errors->n != 0) {
+            return NULL;
+        }
+    }
+
+    // TODO: Type check basic expressions (e.g. arithmetic/numeric comparisons).
+    // We can't be sure when we have functions unless the return type is known.
+
     return roots;
 }
 
@@ -591,6 +653,7 @@ object_alloc(Token tok, ObjectType type) {
     node->line = tok.line;
     node->col = tok.col;
     node->type = type;
+    node->visited = false;
     array_push(objects, node);
     return node;
 }
@@ -739,13 +802,9 @@ object_equal(Object *a, Object *b) {
                     return false;
                 }
             }
+            return true;
         } break;
-        case OBJ_TYPE_LAMBDA: {
-            // return a->closure == b.closure;
-        } break;
-        default: {
-            return false;
-        } break;
+        default: break;
     }
-    return true;
+    return false;
 }
-- 
cgit v1.2.1