wip: working on analyzer

- Feat: implement return analyzer
- Fix: add block return check if inside function

src/compiler/analyzer/an_block.c

@@ -1,11 +1,16 @@
 #include <common/fzl_types.h>
 #include <compiler/fzl_analyzer.h>
 #include <compiler/fzl_parser.h>
+#include <compiler/fzl_token.h>
 #include <stddef.h>
 #include <stdio.h>
 
 char block_problem[256];
 
+// defined in `compiler/analyzer/utility.c`
+extern fzl_type_t an_toktotype(fzl_token_t *tok);
+extern char *an_typetostr(fzl_type_t type, char *classname);
+
 // Analyze block
 fzl_an_res_t analyze_block(fzl_analyzer_t *analyzer, fzl_node_t *block_node)
 {
@@ -38,6 +43,48 @@ fzl_an_res_t analyze_block(fzl_analyzer_t *analyzer, fzl_node_t *block_node)
       has_return = true;
   }
 
+  fzl_an_ctx_t *fnctx = analyzer->ctx;
+  while (fnctx != NULL)
+  {
+    if (fnctx->type == FZL_AN_CTX_TYPE_FUNCTION)
+      break;
+
+    fnctx = fnctx->parent;
+  }
+
+  if (fnctx && fnctx->type == FZL_AN_CTX_TYPE_FUNCTION)
+  {
+    fzl_type_t rettype = an_toktotype(fnctx->fn->fn.type);
+    char *classname    = NULL;
+    char *rettype_str  = an_typetostr(rettype, classname);
+
+    if (rettype == FZL_TYPE_OBJECT)
+      classname = (char *)fnctx->fn->fn.type->value;
+
+    if (rettype != FZL_TYPE_NULL)
+    {
+      if (!has_return || block_node->list.entry_count < 1)
+      {
+        snprintf(block_problem, sizeof(block_problem),
+                 "expected 'return <%s>' in function because return type is %s",
+                 rettype_str, rettype_str);
+        an_push_error(analyzer, block_node->token, block_problem);
+        return (fzl_an_res_t){.error = true};
+      }
+
+      fzl_node_t *last_node =
+          block_node->list.entries[block_node->list.entry_count - 1];
+      if (last_node->type != FZL_NODETYPE_RETURN)
+      {
+        snprintf(block_problem, sizeof(block_problem),
+                 "expected last statement in block to be 'return <%s>'",
+                 rettype_str);
+        an_push_error(analyzer, last_node->token, block_problem);
+        return (fzl_an_res_t){.error = true};
+      }
+    }
+  }
+
   an_fin_ctx(analyzer);
 
   return (fzl_an_res_t){.error = error, .type = FZL_TYPE_NULL};