Completed lambda implementation of functions.

Hooray! 🎉

src/grammar.y

@@ -129,7 +129,12 @@ exp:
     // Number.
     NUM { $$ = ast_init(AST_TYPE_NUM, ast_num_data_init($1)); }
 
-    // Call.
+    // Variable reference.
+    | WORD {
+        $$ = ast_init(AST_TYPE_VREF, ast_vref_data_init($1));
+    }
+
+    // Call (general form).
     | exp GROUPS arg GROUPE {
         size_t argc = $3->ln;
         AST** argv = $3->buf;
@@ -141,6 +146,18 @@ exp:
         ));
     }
 
+    // Call (convenient form).
+    | WORD GROUPS arg GROUPE {
+        size_t argc = $3->ln;
+        AST** argv = $3->buf;
+        argarr_destroypsv($3);
+        $$ = ast_init(AST_TYPE_CALL, ast_call_data_init(
+            argc,
+            argv,
+            ast_init(AST_TYPE_VREF, ast_vref_data_init($1))
+        ));
+    }
+
     // Function definitions. Convert to VDef of Lambda.
     | WORD GROUPS arg GROUPE exp {
         size_t parc = $3->ln;
@@ -191,11 +208,6 @@ exp:
         $$ = ast_init(AST_TYPE_VDEF, ast_vdef_data_init($1, $3));
     }
 
-    // Variable reference.
-    | WORD {
-        $$ = ast_init(AST_TYPE_VREF, ast_vref_data_init($1));
-    }
-
     | exp ADD exp {
         AST** argv = calloc(2, sizeof(AST*));
         argv[0] = $1;