From 0b57cdff82174af573fdd668d1bff36d41712b79 Mon Sep 17 00:00:00 2001
From: AnotherTest <ali.mpfard@gmail.com>
Date: Sun, 13 Sep 2020 13:59:34 +0430
Subject: [PATCH] Shell: Add support for $0,$1,...

---
 Shell/Shell.cpp | 28 ++++++++++++++++++++++++++++
 Shell/Shell.h   |  3 +++
 Shell/main.cpp  |  2 ++
 3 files changed, 33 insertions(+)

diff --git a/Shell/Shell.cpp b/Shell/Shell.cpp
index b3b406e0e5..057c1357c1 100644
--- a/Shell/Shell.cpp
+++ b/Shell/Shell.cpp
@@ -333,6 +333,33 @@ RefPtr<AST::Value> Shell::lookup_local_variable(const String& name)
     if (auto* frame = find_frame_containing_local_variable(name))
         return frame->local_variables.get(name).value();
 
+    if (auto index = name.to_uint(); index.has_value())
+        return get_argument(index.value());
+
+    return nullptr;
+}
+
+RefPtr<AST::Value> Shell::get_argument(size_t index)
+{
+    if (index == 0)
+        return adopt(*new AST::StringValue(current_script));
+
+    --index;
+    if (auto argv = lookup_local_variable("ARGV")) {
+        if (argv->is_list_without_resolution()) {
+            AST::ListValue* list = static_cast<AST::ListValue*>(argv.ptr());
+            if (list->values().size() <= index)
+                return nullptr;
+
+            return list->values().at(index);
+        }
+
+        if (index != 0)
+            return nullptr;
+
+        return argv;
+    }
+
     return nullptr;
 }
 
@@ -750,6 +777,7 @@ NonnullRefPtrVector<Job> Shell::run_commands(Vector<AST::Command>& commands)
 
 bool Shell::run_file(const String& filename, bool explicitly_invoked)
 {
+    TemporaryChange script_change { current_script, filename };
     auto file_result = Core::File::open(filename, Core::File::ReadOnly);
     if (file_result.is_error()) {
         if (explicitly_invoked)
diff --git a/Shell/Shell.h b/Shell/Shell.h
index 9f168f8116..a95d73aafd 100644
--- a/Shell/Shell.h
+++ b/Shell/Shell.h
@@ -92,6 +92,7 @@ public:
     String resolve_path(String) const;
     String resolve_alias(const String&) const;
 
+    RefPtr<AST::Value> get_argument(size_t);
     RefPtr<AST::Value> lookup_local_variable(const String&);
     String local_variable_or(const String&, const String&);
     void set_local_variable(const String&, RefPtr<AST::Value>);
@@ -170,6 +171,8 @@ public:
     HashMap<u64, NonnullRefPtr<Job>> jobs;
     Vector<String, 256> cached_path;
 
+    String current_script;
+
     enum ShellEventType {
         ReadLine,
     };
diff --git a/Shell/main.cpp b/Shell/main.cpp
index 83877ccfad..5961086680 100644
--- a/Shell/main.cpp
+++ b/Shell/main.cpp
@@ -209,6 +209,8 @@ int main(int argc, char** argv)
 
     parser.parse(argc, argv);
 
+    shell->current_script = argv[0];
+
     if (!skip_rc_files) {
         auto run_rc_file = [&](auto& name) {
             String file_path = name;