diff --git a/src/main.cpp b/src/main.cpp
index 0955be9..40223ec 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -166,7 +166,7 @@ void execute(const std::string& file,
     }
 
     // run
-    auto start = clk::now();
+    const auto start = clk::now();
     if (cmd&VM_DEBUG) {
         auto debugger = std::unique_ptr<nasal::dbg>(new nasal::dbg);
         debugger->run(gen, ld, argv, cmd&VM_PROFILE, cmd&VM_PROF_ALL);
@@ -178,7 +178,7 @@ void execute(const std::string& file,
     }
 
     // get running time
-    auto end = clk::now();
+    const auto end = clk::now();
     if (cmd&VM_TIME) {
         std::clog << "process exited after ";
         std::clog << (end-start).count()*1.0/den << "s.\n\n";
@@ -211,7 +211,7 @@ i32 main(i32 argc, const char* argv[]) {
     }
 
     // execute with arguments
-    const std::unordered_map<std::string, u32> cmdlst = {
+    const std::unordered_map<std::string, u32> command_list = {
         {"--raw-ast", VM_RAW_AST},
         {"--ast", VM_AST},
         {"-a", VM_AST},
@@ -233,12 +233,13 @@ i32 main(i32 argc, const char* argv[]) {
         {"--ref-file", VM_REF_FILE},
         {"--limit", VM_LIMIT|VM_EXEC}
     };
-    u32 cmd = 0;
+
+    u32 commands = 0;
     std::string filename = "";
     std::vector<std::string> vm_argv;
     for(i32 i = 1; i<argc; ++i) {
-        if (cmdlst.count(argv[i])) {
-            cmd |= cmdlst.at(argv[i]);
+        if (command_list.count(argv[i])) {
+            commands |= command_list.at(argv[i]);
         } else if (!filename.length()) {
             filename = argv[i];
         } else {
@@ -248,6 +249,7 @@ i32 main(i32 argc, const char* argv[]) {
     if (!filename.length()) {
         err();
     }
-    execute(filename, vm_argv, cmd? cmd:VM_EXEC);
+
+    execute(filename, vm_argv, commands? commands:VM_EXEC);
     return 0;
 }
\ No newline at end of file
diff --git a/src/nasal.h b/src/nasal.h
index 26894d0..0c59625 100644
--- a/src/nasal.h
+++ b/src/nasal.h
@@ -1,7 +1,7 @@
 #pragma once
 
 #ifndef __nasver__
-#define __nasver__ "11.1"
+#define __nasver__ "11.2"
 #endif
 
 #include <cstdint>
diff --git a/src/nasal_gc.cpp b/src/nasal_gc.cpp
index e402447..215c08a 100644
--- a/src/nasal_gc.cpp
+++ b/src/nasal_gc.cpp
@@ -222,7 +222,7 @@ void gc::init(
             continue;
         }
         strs[i] = var::gcobj(new nas_val(vm_type::vm_str));
-        strs[i].val.gcobj->unmutable = 1;
+        strs[i].val.gcobj->immutable = 1;
         strs[i].str() = constant_strings[i];
     }
 
@@ -234,7 +234,7 @@ void gc::init(
             continue;
         }
         env_argv[i] = var::gcobj(new nas_val(vm_type::vm_str));
-        env_argv[i].val.gcobj->unmutable = 1;
+        env_argv[i].val.gcobj->immutable = 1;
         env_argv[i].str() = argv[i];
     }
 }
diff --git a/src/nasal_lexer.h b/src/nasal_lexer.h
index 4c57f8e..bd0a778 100644
--- a/src/nasal_lexer.h
+++ b/src/nasal_lexer.h
@@ -177,7 +177,8 @@ private:
     token dots();
     token calc_opr();
 public:
-    lexer(): line(1), column(0), ptr(0), filename(""), res(""), invalid_char(0) {}
+    lexer(): line(1), column(0), ptr(0),
+             filename(""), res(""), invalid_char(0) {}
     const error& scan(const std::string&);
     const std::vector<token>& result() const {return toks;}
 };
diff --git a/src/nasal_type.cpp b/src/nasal_type.cpp
index 0587f27..5b3cf20 100644
--- a/src/nasal_type.cpp
+++ b/src/nasal_type.cpp
@@ -198,7 +198,7 @@ std::ostream& operator<<(std::ostream& out, nas_map& mp) {
 nas_val::nas_val(vm_type val_type) {
     mark = gc_status::collected;
     type = val_type;
-    unmutable = 0;
+    immutable = 0;
     switch(val_type) {
         case vm_type::vm_str:   ptr.str = new std::string; break;
         case vm_type::vm_vec:   ptr.vec = new nas_vec;     break;
diff --git a/src/nasal_type.h b/src/nasal_type.h
index a217996..7cd3f17 100644
--- a/src/nasal_type.h
+++ b/src/nasal_type.h
@@ -250,7 +250,7 @@ struct nas_map {
 };
 
 struct nas_val {
-    enum class gc_status:u8 {
+    enum class gc_status: u8 {
         uncollected = 0,   
         collected,
         found
@@ -258,7 +258,7 @@ struct nas_val {
 
     gc_status mark;
     vm_type type; // value type
-    u8 unmutable; // used to mark if a string is unmutable
+    u8 immutable; // used to mark if a string is immutable
     union {
         std::string* str;
         nas_vec*   vec;
diff --git a/src/natives/bits_lib.cpp b/src/natives/bits_lib.cpp
index 1ccfe6d..61576c5 100644
--- a/src/natives/bits_lib.cpp
+++ b/src/natives/bits_lib.cpp
@@ -48,7 +48,7 @@ var builtin_fld(context* ctx, gc* ngc) {
     auto str = local[1];
     auto startbit = local[2];
     auto length = local[3];
-    if (!str.is_str() || str.val.gcobj->unmutable) {
+    if (!str.is_str() || str.val.gcobj->immutable) {
         return nas_err("bits::fld", "\"str\" must be mutable string");
     }
     if (!startbit.is_num() || !length.is_num()) {
@@ -78,7 +78,7 @@ var builtin_sfld(context* ctx, gc* ngc) {
     auto str = local[1];
     auto startbit = local[2];
     auto length = local[3];
-    if (!str.is_str() || str.val.gcobj->unmutable) {
+    if (!str.is_str() || str.val.gcobj->immutable) {
         return nas_err("bits::sfld", "\"str\" must be mutable string");
     }
     if (!startbit.is_num() || !length.is_num()) {
@@ -112,7 +112,7 @@ var builtin_setfld(context* ctx, gc* ngc) {
     auto startbit = local[2];
     auto length = local[3];
     auto value = local[4];
-    if (!str.is_str() || str.val.gcobj->unmutable) {
+    if (!str.is_str() || str.val.gcobj->immutable) {
         return nas_err("bits::setfld", "\"str\" must be mutable string");
     }
     if (!startbit.is_num() || !length.is_num() || !value.is_num()) {
diff --git a/src/natives/io_lib.cpp b/src/natives/io_lib.cpp
index 9fb4cfc..7f9b469 100644
--- a/src/natives/io_lib.cpp
+++ b/src/natives/io_lib.cpp
@@ -84,7 +84,7 @@ var builtin_read(context* ctx, gc* ngc) {
     if (!file_descriptor.object_check(file_type_name)) {
         return nas_err("io::read", "not a valid filehandle");
     }
-    if (!buffer.is_str() || buffer.val.gcobj->unmutable) {
+    if (!buffer.is_str() || buffer.val.gcobj->immutable) {
         return nas_err("io::read", "\"buf\" must be mutable string");
     }
     if (!length.is_num()) {
@@ -102,7 +102,7 @@ var builtin_read(context* ctx, gc* ngc) {
         static_cast<FILE*>(file_descriptor.ghost().pointer)
     );
     buffer.str() = temp_buffer;
-    buffer.val.gcobj->unmutable = true;
+    buffer.val.gcobj->immutable = true;
     delete []temp_buffer;
     return var::num(read_size);
 }