From 165ead4adbf8494db82f7be35c6f8d52ac47ebef Mon Sep 17 00:00:00 2001
From: _ov4 <ov4@ov4.org>
Date: Tue, 15 Sep 2026 13:48:09 +0000
Subject: add subshell ast prepare for real subshell and expansion

---
 include/lexer/ast.h       |  2 ++
 module-test/lexer_test.cc | 23 ++++++++++++++++++++---
 src/lexer/ast.cc          | 20 ++++++++++++++++++++
 3 files changed, 42 insertions(+), 3 deletions(-)

diff --git a/include/lexer/ast.h b/include/lexer/ast.h
index 3434aa3..d4b0fd5 100644
--- a/include/lexer/ast.h
+++ b/include/lexer/ast.h
@@ -20,6 +20,8 @@ public:
     string command_text;
     size_t left = string::npos;
     size_t right = string::npos;
+
+    bool subshell;
 };
 
 }
diff --git a/module-test/lexer_test.cc b/module-test/lexer_test.cc
index 623b9ec..364c890 100644
--- a/module-test/lexer_test.cc
+++ b/module-test/lexer_test.cc
@@ -6,7 +6,9 @@ g++ \
     src/lexer/token.cc \
     src/lexer/ast.cc \
     src/lexer/symbol_property.cc \
-    -std=c++23 -Iinclude -Ithird_party/magic_enum/include 
+    -std=c++23 -Iinclude -Ithird_party/magic_enum/include \
+    -O0 -ggdb3 -fno-omit-frame-pointer -fno-inline -D_GLIBCXX_ASSERTIONS \
+    -o module-test/lexer_test.out
 */
 
 #include <iostream>
@@ -35,7 +37,7 @@ constexpr int MAXLINE = 1024;
 int main()
 {
     verbose = true;
-    int test_case = 13;
+    int test_case = 15;
     string s;
 
     switch (test_case)
@@ -104,6 +106,16 @@ int main()
             s = "alpha&beta";
             break;
 
+        // simple subshell test
+        case 14:
+            s = "alpha && (beta)";
+            break;
+
+        // complex subshell test
+        case 15:
+            s = "alpha && (beta || gamma) && (sleep &)";
+            break;
+
         default:
             return 0;
     }
@@ -138,7 +150,12 @@ int main()
         cout << "---------- AST ----------" << endl;
         for (size_t i = 0; i < lexer_instance.ast.size(); i++)
         {
-            print("{}: type: {} left: {} right: {}", i, magic_enum::enum_name(lexer_instance.ast[i].token_type), lexer_instance.ast[i].left, lexer_instance.ast[i].right);
+            print("{}: type: {} left: {} right: {}, subshell {}", 
+                i, 
+                magic_enum::enum_name(lexer_instance.ast[i].token_type), 
+                lexer_instance.ast[i].left, 
+                lexer_instance.ast[i].right,
+                lexer_instance.ast[i].subshell ? "TRUE" : "FALSE");
             if (lexer_instance.ast[i].token_type == TEXT)
                 print(" command: {}", lexer_instance.ast[i].command_text);
             println();
diff --git a/src/lexer/ast.cc b/src/lexer/ast.cc
index 55b4c42..292728b 100644
--- a/src/lexer/ast.cc
+++ b/src/lexer/ast.cc
@@ -10,6 +10,7 @@
 #include "lexer/symbol_property.h"
 #include "util/io.h"
 #include "error.h"
+#include "magic_enum/magic_enum.hpp"
 
 using namespace std;
 
@@ -62,6 +63,25 @@ void T_lexer::parse(size_t cmd_begin, size_t cmd_end, size_t ast_vec)
     int max_depth = -1;
     size_t found_pos = string::npos;
 
+    // if it's fully inside bracket
+    // then it's subshell
+    loggerln("parse: left token type: {}, right: {}", 
+        magic_enum::enum_name(token[cmd_begin].token_type), 
+        magic_enum::enum_name(token[cmd_end-1].token_type));
+    if (token[cmd_begin].token_type == LEFT_BRACKET && token[cmd_end-1].token_type == RIGHT_BRACKET)
+    {
+        ast[ast_vec].subshell = true;
+        loggerln("parse: detect subshell {}", ast_vec);
+
+        // eat () subshell token
+        cmd_begin++;
+        cmd_end--;
+    }
+    else 
+    {
+        ast[ast_vec].subshell = false;
+    }
+
     for (size_t i = cmd_begin; i < cmd_end; i++)
     {
         if (token[i].bracket_depth > max_depth)
-- 
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