diff --git a/compiler/erg_common/traits.rs b/compiler/erg_common/traits.rs
index 3109b555..c92ad3bf 100644
--- a/compiler/erg_common/traits.rs
+++ b/compiler/erg_common/traits.rs
@@ -386,6 +386,7 @@ pub trait Runnable: Sized + Default {
     const NAME: &'static str;
     fn new(cfg: ErgConfig) -> Self;
     fn cfg(&self) -> &ErgConfig;
+    fn cfg_mut(&mut self) -> &mut ErgConfig;
     fn finish(&mut self); // called when the :exit command is received.
     /// Erase all but immutable information.
     fn initialize(&mut self);
@@ -397,6 +398,9 @@ pub trait Runnable: Sized + Default {
     fn input(&self) -> &Input {
         &self.cfg().input
     }
+    fn set_input(&mut self, input: Input) {
+        self.cfg_mut().input = input;
+    }
     fn start_message(&self) -> String {
         format!(
             "{} {SEMVER} (tags/?:{GIT_HASH_SHORT}, {BUILD_DATE}) on {ARCH}/{OS}\n",
diff --git a/compiler/erg_compiler/build_hir.rs b/compiler/erg_compiler/build_hir.rs
index 9321eeb5..74a7b7c2 100644
--- a/compiler/erg_compiler/build_hir.rs
+++ b/compiler/erg_compiler/build_hir.rs
@@ -40,6 +40,10 @@ impl Runnable for HIRBuilder {
     fn cfg(&self) -> &ErgConfig {
         self.lowerer.cfg()
     }
+    #[inline]
+    fn cfg_mut(&mut self) -> &mut ErgConfig {
+        self.lowerer.cfg_mut()
+    }
 
     #[inline]
     fn finish(&mut self) {}
diff --git a/compiler/erg_compiler/compile.rs b/compiler/erg_compiler/compile.rs
index c4f68338..daf89106 100644
--- a/compiler/erg_compiler/compile.rs
+++ b/compiler/erg_compiler/compile.rs
@@ -127,6 +127,10 @@ impl Runnable for Compiler {
     fn cfg(&self) -> &ErgConfig {
         &self.cfg
     }
+    #[inline]
+    fn cfg_mut(&mut self) -> &mut ErgConfig {
+        &mut self.cfg
+    }
 
     #[inline]
     fn finish(&mut self) {}
diff --git a/compiler/erg_compiler/lower.rs b/compiler/erg_compiler/lower.rs
index e528afeb..4a4ad181 100644
--- a/compiler/erg_compiler/lower.rs
+++ b/compiler/erg_compiler/lower.rs
@@ -71,6 +71,10 @@ impl Runnable for ASTLowerer {
     fn cfg(&self) -> &ErgConfig {
         &self.cfg
     }
+    #[inline]
+    fn cfg_mut(&mut self) -> &mut ErgConfig {
+        &mut self.cfg
+    }
 
     fn new(cfg: ErgConfig) -> Self {
         Self::new_with_cache(
diff --git a/compiler/erg_compiler/transpile.rs b/compiler/erg_compiler/transpile.rs
index eaed716f..2e7494d6 100644
--- a/compiler/erg_compiler/transpile.rs
+++ b/compiler/erg_compiler/transpile.rs
@@ -124,6 +124,10 @@ impl Runnable for Transpiler {
     fn cfg(&self) -> &ErgConfig {
         &self.cfg
     }
+    #[inline]
+    fn cfg_mut(&mut self) -> &mut ErgConfig {
+        &mut self.cfg
+    }
 
     #[inline]
     fn finish(&mut self) {}
diff --git a/compiler/erg_parser/build_ast.rs b/compiler/erg_parser/build_ast.rs
index 5dcb6a98..c4fdf587 100644
--- a/compiler/erg_parser/build_ast.rs
+++ b/compiler/erg_parser/build_ast.rs
@@ -29,6 +29,10 @@ impl Runnable for ASTBuilder {
     fn cfg(&self) -> &ErgConfig {
         self.runner.cfg()
     }
+    #[inline]
+    fn cfg_mut(&mut self) -> &mut ErgConfig {
+        self.runner.cfg_mut()
+    }
 
     #[inline]
     fn finish(&mut self) {}
diff --git a/compiler/erg_parser/lex.rs b/compiler/erg_parser/lex.rs
index d617a35a..bbde23bf 100644
--- a/compiler/erg_parser/lex.rs
+++ b/compiler/erg_parser/lex.rs
@@ -33,6 +33,10 @@ impl Runnable for LexerRunner {
     fn cfg(&self) -> &ErgConfig {
         &self.cfg
     }
+    #[inline]
+    fn cfg_mut(&mut self) -> &mut ErgConfig {
+        &mut self.cfg
+    }
 
     #[inline]
     fn finish(&mut self) {}
diff --git a/compiler/erg_parser/parse.rs b/compiler/erg_parser/parse.rs
index ca8bb6ed..70c0ef13 100644
--- a/compiler/erg_parser/parse.rs
+++ b/compiler/erg_parser/parse.rs
@@ -183,6 +183,10 @@ impl Runnable for ParserRunner {
     fn cfg(&self) -> &ErgConfig {
         &self.cfg
     }
+    #[inline]
+    fn cfg_mut(&mut self) -> &mut ErgConfig {
+        &mut self.cfg
+    }
 
     #[inline]
     fn finish(&mut self) {}
diff --git a/src/dummy.rs b/src/dummy.rs
index 94d30d43..0f0d1d4a 100644
--- a/src/dummy.rs
+++ b/src/dummy.rs
@@ -48,6 +48,10 @@ impl Runnable for DummyVM {
     fn cfg(&self) -> &ErgConfig {
         &self.compiler.cfg
     }
+    #[inline]
+    fn cfg_mut(&mut self) -> &mut ErgConfig {
+        &mut self.compiler.cfg
+    }
 
     fn new(cfg: ErgConfig) -> Self {
         let stream = if cfg.input.is_repl() {