From 37f703d1252d39047ab71ef15c62855e44de897b Mon Sep 17 00:00:00 2001
From: Bad Diode <bd@badd10de.dev>
Date: Tue, 18 Jun 2024 14:15:37 +0200
Subject: Add pointers

---
 src/main.c          | 54 ++++++++++++++++++++++++++++++++++-------------------
 tests/variables.bad |  8 ++++++++
 2 files changed, 43 insertions(+), 19 deletions(-)

diff --git a/src/main.c b/src/main.c
index 57d09bd..3454587 100644
--- a/src/main.c
+++ b/src/main.c
@@ -76,7 +76,7 @@ typedef enum NodeKind {
     NODE_SET,
     NODE_STRUCT,
     // Helpers.
-    NODE_SYMBOL_ARR,
+    NODE_SYMBOL_IDX,
     NODE_TYPE,
     NODE_ARR_TYPE,
     NODE_COMPOUND_TYPE,
@@ -123,7 +123,7 @@ Str node_str[] = {
     // Helpers.
     [NODE_TYPE] = cstr("TYPE"),
     [NODE_ARR_TYPE] = cstr("TYPE (ARR)"),
-    [NODE_SYMBOL_ARR] = cstr("SYMBOL (ARR)"),
+    [NODE_SYMBOL_IDX] = cstr("SYMBOL[IDX]"),
     [NODE_COMPOUND_TYPE] = cstr("TYPE (COMPOUND)"),
     [NODE_STRUCT_FIELD] = cstr("FIELD"),
 };
@@ -161,6 +161,7 @@ typedef struct Node {
         struct Node **struct_field;
         struct Node **elements;
     };
+    bool is_ptr;
 } Node;
 
 //
@@ -223,6 +224,7 @@ void parse_type(Parser *parser);
 ParseRule parse_rules[] = {
     [TOK_LPAREN] = {parse_grouping, NULL, PREC_NONE},
     [TOK_LCURLY] = {NULL, NULL, PREC_NONE},
+    [TOK_AT] = {parse_symbol, NULL, PREC_NONE},
 
     // Arithmetic.
     [TOK_SUB] = {parse_unary, parse_binary, PREC_TERM},
@@ -401,6 +403,9 @@ parse_type(Parser *parser) {
 #endif
     Node *node = node_alloc(parser, NODE_TYPE, prev);
     if (!node) return;
+    if (parse_match(parser, TOK_AT)) {
+        node->is_ptr = true;
+    }
     if (parse_match(parser, TOK_LCURLY)) {
         node->kind = NODE_COMPOUND_TYPE;
         while (!parse_match(parser, TOK_RCURLY) && !parser->panic) {
@@ -419,8 +424,7 @@ parse_type(Parser *parser) {
         // Optional array value?
         if (parse_match(parser, TOK_LSQUARE)) {
             node->kind = NODE_ARR_TYPE,
-            parse_consume(parser, TOK_NUM_INT,
-                          cstr("no array size given"));
+            parse_consume(parser, TOK_NUM_INT, cstr("no array size given"));
             parse_number(parser);
             node->arr_size = array_pop(parser->nodes);
             parse_consume(parser, TOK_RSQUARE,
@@ -626,20 +630,28 @@ parse_symbol(Parser *parser) {
     print("parsing symbol ");
     print_token(prev);
 #endif
-    Node *node;
+    if (prev.kind == TOK_AT) {
+        parse_consume(parser, TOK_SYMBOL,
+                      cstr("expected symbol after '.' operator"));
+        parse_symbol(parser);
+        Node *node = array_pop(parser->nodes);
+        if (node) {
+            node->is_ptr = true;
+            array_push(parser->nodes, node, parser->storage);
+        }
+        return;
+    }
+    Node *node = node_alloc(parser, NODE_SYMBOL, prev);
+    if (!node) return;
     if (parse_match(parser, TOK_DOT)) {
         // Symbol chain.
         parse_consume(parser, TOK_SYMBOL,
                       cstr("expected symbol after '.' operator"));
-        node = node_alloc(parser, NODE_SYMBOL, prev);
-        if (!node) return;
         parse_symbol(parser);
         node->next = array_pop(parser->nodes);
     } else if (parse_match(parser, TOK_LCURLY)) {
         // Struct literal.
-        node = node_alloc(parser, NODE_STRUCT_LIT, prev);
-        if (!node) return;
-
+        node->kind = NODE_STRUCT_LIT;
         while (!parse_match(parser, TOK_RCURLY) && !parser->panic) {
             Node *field =
                 node_alloc(parser, NODE_STRUCT_FIELD, parser->current);
@@ -652,14 +664,12 @@ parse_symbol(Parser *parser) {
             array_push(node->elements, field, parser->storage);
         }
     } else if (parse_match(parser, TOK_LSQUARE)) {
-        node = node_alloc(parser, NODE_SYMBOL_ARR, prev);
-        if (!node) return;
-        parse_consume(parser, TOK_NUM_INT,
-                        cstr("no array size given"));
+        node->kind = NODE_SYMBOL_IDX;
+        parse_consume(parser, TOK_NUM_INT, cstr("no array size given"));
         parse_number(parser);
         node->arr_size = array_pop(parser->nodes);
         parse_consume(parser, TOK_RSQUARE,
-                        cstr("unmatched brackets ']' in array type"));
+                      cstr("unmatched brackets ']' in array type"));
     } else {
         node = node_alloc(parser, NODE_SYMBOL, prev);
         if (!node) return;
@@ -690,11 +700,17 @@ graph_node(Node *node) {
         case NODE_NUM_UINT: print("| Value: %x", node->value.u); break;
         case NODE_NUM_FLOAT: print("| Value: %f{2}", node->value.d); break;
         case NODE_STRING: print("| Value: %s", node->value.str); break;
-        case NODE_SYMBOL_ARR: print("| Name: %s", node->value.sym); break;
-        case NODE_SYMBOL: print("| Name: %s", node->value.sym); break;
-        case NODE_STRUCT: print("| Name: %s", node->value.sym); break;
+        case NODE_SYMBOL_IDX: 
+        case NODE_STRUCT: 
         case NODE_STRUCT_LIT: print("| Name: %s", node->value.sym); break;
-        case NODE_TYPE: print("| Name: %s", node->value.sym); break;
+        case NODE_SYMBOL: 
+        case NODE_TYPE: {
+            if (node->is_ptr) {
+                print("| Name: @%s", node->value.sym);
+            } else {
+                print("| Name: %s", node->value.sym);
+            }
+        } break;
         default: break;
     }
     println("\"];");
diff --git a/tests/variables.bad b/tests/variables.bad
index 473bb3c..990685f 100644
--- a/tests/variables.bad
+++ b/tests/variables.bad
@@ -58,3 +58,11 @@ let particle = entity {
 let numbers: u32[0xff]
 set numbers[0] = 32
 set numbers[1] = 42
+
+; Arrays are syntactic sugar for pointers (@).
+let ptr:@u32 = numbers
+set ptr[10] = 33
+
+; Strings hold a .mem and .size fields with the number of bytes it holds.
+let hello: str = "hello world"
+set c[1] = 'a' ; "hallo world"
-- 
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