diff --git a/modules/eth/vm.cpp b/modules/eth/vm.cpp
index abe3618..3384840 100644
--- a/modules/eth/vm.cpp
+++ b/modules/eth/vm.cpp
@@ -44,6 +44,7 @@ var_evm_t::var_evm_t( vm_state_t * vm, const int parse_ctr )
 var_evm_t::~var_evm_t()
 {
 	if( !m_copied ) {
+		m_vm->srclist.clear();
 		m_vm->srcstack.pop_back();
 		delete m_vm;
 	}
@@ -87,13 +88,14 @@ var_base_t * vm_create( vm_state_t & vm, func_call_data_t & fcd )
 	src_t * src = new src_t( true );
 	src->ptree = new parse_tree_t;
 	src->dir = vm.srcstack.back()->dir;
+	src->id = 0;
 	src->file = fcd.args.size() > 1 ? fcd.args[ 0 ]->to_str() : "<repl>";
-	src->id = src->file;
 
 	vm_state_t * v = new vm_state_t();
 
 	v->flags = vm.flags;
 	v->srcstack.push_back( src );
+	v->srclist.push_back( src->file );
 	v->srcs[ src->id ] = src;
 	v->vars->add( "nil", v->nil );
 
@@ -143,7 +145,7 @@ var_base_t * vm_exec_code( vm_state_t & vm, func_call_data_t & fcd )
 	src_t * s = v->srcstack.back();
 	src_t src( false );
 	src.file = s->file;
-	src.id = s->file;
+	src.id = s->id;
 
 	size_t code_size = s->code.size();
 	size_t toks_size = s->toks.size();
diff --git a/src/FE/Ethereal.hpp b/src/FE/Ethereal.hpp
index 38d23f4..951417c 100644
--- a/src/FE/Ethereal.hpp
+++ b/src/FE/Ethereal.hpp
@@ -20,9 +20,10 @@
 
 struct src_t
 {
-	// id is unique and used as the srcs map's key
-	// file is the name (no dir part) of the source file
-	std::string id;
+	// id is unique and used for mapping variables to sources
+	// file is the name (no dir part) of the source file and is used
+	// as key for srcs map.
+	int id;
 	std::string file;
 	std::string dir;
 	std::vector< std::string > code;
@@ -57,6 +58,6 @@ struct src_t
 	src.bcode.push_back( { m_tok_ctr, line, col, IC_REM_SCOPE, { OP_INT, "1" } } );	\
 	if( src.block_depth.back().size() > 0 ) --src.block_depth.back().back()
 
-typedef std::unordered_map< std::string, src_t * > srcs_t;
+typedef std::unordered_map< int, src_t * > srcs_t;
 
 #endif // ETHEREAL_HPP
\ No newline at end of file
diff --git a/src/FE/Main.cpp b/src/FE/Main.cpp
index 4b82576..936465e 100644
--- a/src/FE/Main.cpp
+++ b/src/FE/Main.cpp
@@ -48,8 +48,8 @@ int main( int argc, char ** argv )
 	const std::string main_src_str = args[ 0 ].substr( last_slash_loc + 1 );
 
 	src_t * main_src = new src_t( true );
+	main_src->id = 0;
 	main_src->file = main_src_str;
-	main_src->id = "main_src_" + main_src->file;
 	main_src->dir = src_dir;
 	err = tokenize( * main_src );
 	if( err != E_OK ) goto cleanup;
@@ -98,6 +98,7 @@ int main( int argc, char ** argv )
 		vm_state_t vm;
 		vm.flags = flags;
 		vm.srcstack.push_back( main_src );
+		vm.srclist.push_back( main_src->file );
 		vm.srcs[ main_src->id ] = main_src;
 		if( !set_init_mods( vm ) ) { err = E_VM_FAIL; goto end; }
 		std::vector< var_base_t * > arg_vec;
@@ -113,6 +114,7 @@ int main( int argc, char ** argv )
 		vm.vars->add( "false", new var_bool_t( false, 0 ) );
 		vm.vars->add( "nil", vm.nil );
 		err = vm_exec( vm );
+		vm.srclist.clear();
 		vm.srcstack.pop_back();
 		goto end;
 	}
diff --git a/src/VM/Core.hpp b/src/VM/Core.hpp
index fe09ea8..9aa756c 100644
--- a/src/VM/Core.hpp
+++ b/src/VM/Core.hpp
@@ -18,6 +18,7 @@
 extern const char * LIB_EXT;
 
 typedef std::vector< src_t * > src_stack_t;
+typedef std::vector< std::string > src_list_t;
 
 typedef std::unordered_map< std::string, functions_t > type_funcs_t;
 
@@ -36,6 +37,7 @@ struct vm_state_t
 	var_nil_t * nil;
 
 	src_stack_t srcstack;
+	src_list_t srclist;
 	srcs_t srcs;
 
 	vars_t * vars;
diff --git a/src/VM/ExecInternal.cpp b/src/VM/ExecInternal.cpp
index b5d44c7..93d79ef 100644
--- a/src/VM/ExecInternal.cpp
+++ b/src/VM/ExecInternal.cpp
@@ -445,7 +445,7 @@ int exec_internal( vm_state_t & vm, long begin, long end, var_base_t * ret )
 					goto fail;
 				}
 				vm.typefuncs[ member_of ].add( function_t{ name, args_min, args_max, args, FnType::LANG,
-								           { .langfn = { src.id.c_str(), blk.beg, blk.end } },
+								           { .langfn = { src.id, blk.beg, blk.end } },
 									   false } );
 			}
 			if( member_ofs.size() == 0 ) {
@@ -455,7 +455,7 @@ int exec_internal( vm_state_t & vm, long begin, long end, var_base_t * ret )
 					goto fail;
 				}
 				vm.funcs.add( function_t{ name, args_min, args_max, args, FnType::LANG,
-					                  { .langfn = { src.id.c_str(), blk.beg, blk.end } },
+					                  { .langfn = { src.id, blk.beg, blk.end } },
 							  false } );
 			}
 			break;
diff --git a/src/VM/Functions.hpp b/src/VM/Functions.hpp
index 92c0150..3f7f486 100644
--- a/src/VM/Functions.hpp
+++ b/src/VM/Functions.hpp
@@ -22,7 +22,7 @@ struct func_call_data_t;
 typedef var_base_t * ( * modfnptr_t )( vm_state_t & vm, func_call_data_t & fcd );
 struct langfn_t
 {
-	const char * src;
+	int src;
 	int beg, end;
 };
 
diff --git a/src/VM/LoadFile.cpp b/src/VM/LoadFile.cpp
index a230a38..996e7f9 100644
--- a/src/VM/LoadFile.cpp
+++ b/src/VM/LoadFile.cpp
@@ -12,6 +12,8 @@
 
 #include "LoadFile.hpp"
 
+static bool src_exists( const srcs_t & srcs, const std::string & file );
+
 int load_src( vm_state_t & vm, const std::string & file )
 {
 	src_t & src = * vm.srcstack.back();
@@ -20,7 +22,7 @@ int load_src( vm_state_t & vm, const std::string & file )
 
 	const std::string new_src_file = file.substr( last_slash_loc + 1 );
 
-	if( vm.srcs.find( new_src_file ) != vm.srcs.end() ) {
+	if( src_exists( vm.srcs, new_src_file ) ) {
 		return E_OK;
 	}
 
@@ -30,8 +32,8 @@ int load_src( vm_state_t & vm, const std::string & file )
 
 	parse_tree_t * ptree = nullptr;
 	src_t * new_src = new src_t( false );
+	new_src->id = vm.srclist.size();
 	new_src->file = new_src_file;
-	new_src->id = new_src_file;
 	new_src->dir = src_dir;
 	err = tokenize( * new_src );
 	if( err != E_OK ) goto cleanup;
@@ -78,6 +80,7 @@ int load_src( vm_state_t & vm, const std::string & file )
 	// actual code execution
 	if( !( vm.flags & OPT_C ) && !( vm.flags & OPT_D ) ) {
 		vm.srcstack.push_back( new_src );
+		vm.srclist.push_back( new_src_file );
 		vm.srcs[ new_src->id ] = new_src;
 		vm.vars->add_zero( vm.vars->layer_size() );
 		err = vm_exec( vm );
@@ -89,4 +92,12 @@ int load_src( vm_state_t & vm, const std::string & file )
 cleanup:
 	if( err != E_OK ) delete new_src;
 	return err;
+}
+
+static bool src_exists( const srcs_t & srcs, const std::string & file )
+{
+	for( auto & item : srcs ) {
+		if( item.second->file == file && !item.second->is_main_src ) return true;
+	}
+	return false;
 }
\ No newline at end of file