From 157cdbf2651503c9ef0b181796d6707faff097ad Mon Sep 17 00:00:00 2001
From: Bad Diode <bd@badd10de.dev>
Date: Fri, 8 Oct 2021 14:30:50 +0200
Subject: Add initial implementation of lists

---
 src/bootstrap/main.c | 76 +++++++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 70 insertions(+), 6 deletions(-)

diff --git a/src/bootstrap/main.c b/src/bootstrap/main.c
index b346cca..a0b0f69 100755
--- a/src/bootstrap/main.c
+++ b/src/bootstrap/main.c
@@ -186,9 +186,16 @@ typedef struct Object {
 
         // OBJ_TYPE_LIST
         struct {
-            struct Object **list_elems;
+            // NOTE: Probably want to do this as a linked list using pairs.
+            struct Object **list;
             size_t list_n;
         };
+
+        // OBJ_TYPE_SYMBOL
+        struct {
+            char *symbol;
+            size_t symbol_n;
+        };
     };
 } Object;
 
@@ -218,18 +225,39 @@ make_string(const char *str, size_t n) {
     return obj;
 }
 
+Object *
+make_symbol(const char *str, size_t n) {
+    Object *obj = malloc(sizeof(Object));
+    obj->type = OBJ_TYPE_SYMBOL;
+    obj->string = malloc(sizeof(char) * n);
+    memcpy(obj->string, str, n);
+    obj->string_n = n;
+    return obj;
+}
+
 Object *
 make_empty_list(void) {
     Object *obj = malloc(sizeof(Object));
-    obj->type = OBJ_TYPE_LIST;
-    obj->list_elems = NULL;
+    obj->type = OBJ_TYPE_NIL;
+    obj->list = NULL;
     obj->list_n = 0;
     return obj;
 }
 
 void
-push_obj_to_list(Object *list, Object obj) {
-    assert(false && "todo: Not implemented");
+push_obj_to_list(Object *list, Object **obj) {
+    assert(list != NULL);
+    assert(list->type == OBJ_TYPE_NIL || list->type == OBJ_TYPE_LIST);
+
+    if (obj == NULL || *obj == NULL) {
+        return;
+    }
+
+    if (list->type == OBJ_TYPE_NIL) {
+        list->type = OBJ_TYPE_LIST;
+    }
+    list->list = realloc(list->list, (list->list_n + 1) * sizeof(struct Object *));
+    list->list[list->list_n++] = *obj;
 }
 
 bool
@@ -287,6 +315,29 @@ build_ast(Tokens tokens) {
         if (sv_equal(token, FALSE_TOKEN)) {
             return make_boolean(false);
         }
+
+        // OBJ_TYPE_LIST
+        if (token.start[0] == ')') {
+            return NULL;
+        }
+        if (token.start[0] == '(') {
+            if ((i + 1) < tokens.n && tokens.start[i + 1].start[0] == ')') {
+                return make_empty_list();
+            }
+
+            Object *list = make_empty_list();
+            Object *next_obj = NULL;
+            while (((i + 1) < tokens.n) && (next_obj = build_ast((Tokens){&tokens.start[i + 1], tokens.n - i - 1})) != NULL) {
+                push_obj_to_list(list, &next_obj);
+                // FIXME: must consume tokens instead, otherwise recursive lists
+                // will not work.
+                i++;
+            }
+            return list;
+        }
+
+        // OBJ_TYPE_SYMBOL
+        return make_symbol(token.start, token.n);
     }
 
     return NULL;
@@ -315,8 +366,21 @@ display(Object *root) {
         case OBJ_TYPE_STRING: {
             printf("\"%.*s\"", (int)root->string_n, root->string);
         } break;
+        case OBJ_TYPE_SYMBOL: {
+            printf(":%.*s", (int)root->symbol_n, root->symbol);
+        } break;
+        case OBJ_TYPE_LIST: {
+            printf("(");
+            for (size_t i = 0; i < root->list_n; i++) {
+                display(root->list[i]);
+                if ((i + 1) < root->list_n) {
+                    printf(" ");
+                }
+            }
+            printf(")");
+        } break;
         default: {
-            printf("TYPE NOT IMPLEMENTED FOR DISPLAY\n");
+            printf("TYPE NOT IMPLEMENTED FOR DISPLAY.");
         } break;
     }
 }
-- 
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