From 3b9cfd8b515d5b2969e242ea730792ae26f5fbfe Mon Sep 17 00:00:00 2001
From: Bad Diode <bd@badd10de.dev>
Date: Wed, 26 Jun 2024 17:36:21 +0200
Subject: Add enum de-structuring and int matching on match expr

---
 src/main.c | 65 +++++++++++++++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 54 insertions(+), 11 deletions(-)

(limited to 'src/main.c')

diff --git a/src/main.c b/src/main.c
index 5c99a10..8026d0d 100644
--- a/src/main.c
+++ b/src/main.c
@@ -8,8 +8,8 @@
 #include "vm.c"
 
 // TODO: unions
-// TODO: match deconstruct enums
 // TODO: arrays and pointers
+// TODO: embed (binary file) and include (source file)
 
 typedef enum ExecMode {
     RUN_NORMAL,
@@ -600,7 +600,7 @@ type_inference(Analyzer *a, Node *node, Scope *scope) {
                     &scope->symbols, field_name,
                     (Symbol){.name = field_name, .kind = SYM_ENUM_FIELD},
                     a->storage);
-                field->type = cstr("int");
+                field->type = symbol;
             }
             symmap_insert(&scope->symbols, symbol,
                           (Symbol){.name = symbol, .kind = SYM_ENUM},
@@ -652,11 +652,57 @@ type_inference(Analyzer *a, Node *node, Scope *scope) {
             node->type = cstr("nil");
             return node->type;
         } break;
-        case NODE_COND:
+        case NODE_COND: {
+            Str previous = cstr("");
+            for (sz i = 0; i < array_size(node->match_cases); i++) {
+                Node *expr = node->match_cases[i];
+                Str next = type_inference(a, expr, scope);
+                if (i != 0 && !str_eq(next, previous)) {
+                    emit_semantic_error(
+                        a, node,
+                        cstr("non-matching types for cond expressions"));
+                    return cstr("");
+                }
+                previous = next;
+            }
+            node->type = previous;
+            return node->type;
+        } break;
         case NODE_MATCH: {
-            // TODO: proper typecheck matchcase expressions here...
-            if (node->match_expr) {
-                type_inference(a, node->match_expr, scope);
+            Str e = type_inference(a, node->match_expr, scope);
+            if (str_eq(e, cstr("int"))) {
+                // Integer matching.
+                for (sz i = 0; i < array_size(node->match_cases); i++) {
+                    Node *field = node->match_cases[i];
+                    if (field->case_value) {
+                        if (field->case_value->kind != NODE_NUM_INT &&
+                            field->case_value->kind != NODE_NUM_UINT) {
+                            emit_semantic_error(
+                                a, field->case_value,
+                                cstr(
+                                    "non-integer or enum types on match case"));
+                        }
+                    }
+                }
+            } else {
+                // Get enum type and de-structure the match.
+                FindEnumResult res = find_enum(scope, e);
+                Str enum_prefix =
+                    str_concat(res.map->val.name, cstr("."), a->storage);
+                for (sz i = 0; i < array_size(node->match_cases); i++) {
+                    Node *field = node->match_cases[i];
+                    if (field->case_value) {
+                        Str field_name = str_concat(
+                            enum_prefix, field->case_value->value.str,
+                            a->storage);
+                        if (!enummap_lookup(&res.scope->enums, field_name)) {
+                            eprintln("%s:%d:%d: error: unknown enum field '%s'",
+                                     a->file_name, field->case_value->line,
+                                     field->case_value->col, field_name);
+                            a->err = true;
+                        }
+                    }
+                }
             }
             Str previous = cstr("");
             for (sz i = 0; i < array_size(node->match_cases); i++) {
@@ -665,7 +711,7 @@ type_inference(Analyzer *a, Node *node, Scope *scope) {
                 if (i != 0 && !str_eq(next, previous)) {
                     emit_semantic_error(
                         a, node,
-                        cstr("non-matching types for case expressions"));
+                        cstr("non-matching types for match expressions"));
                     return cstr("");
                 }
                 previous = next;
@@ -674,9 +720,6 @@ type_inference(Analyzer *a, Node *node, Scope *scope) {
             return node->type;
         } break;
         case NODE_CASE_MATCH: {
-            if (node->case_value) {
-                type_inference(a, node->case_value, scope);
-            }
             if (node->case_expr->kind != NODE_BLOCK) {
                 scope = typescope_alloc(a, scope);
             }
@@ -846,7 +889,7 @@ type_inference(Analyzer *a, Node *node, Scope *scope) {
                     a->err = true;
                     return cstr("");
                 }
-                node->next->type = cstr("int");
+                node->next->type = type->val.name;
                 node->type = type->val.name;
                 return node->next->type;
             }
-- 
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