diff --git a/lib/src/libc/bootstrap.gsc b/lib/src/libc/bootstrap.gsc
index 2580d08..1caad01 100644
--- a/lib/src/libc/bootstrap.gsc
+++ b/lib/src/libc/bootstrap.gsc
@@ -12,5 +12,5 @@ fun main()
 #[nomangle,noreturn,entry]
 fun _start() {
     main()
-    os::exit(0 as i32)
+    std::os::exit(0 as i32)
 }
diff --git a/lib/src/libc/os.gsc b/lib/src/libc/os.gsc
index d4225ee..c7801a4 100644
--- a/lib/src/libc/os.gsc
+++ b/lib/src/libc/os.gsc
@@ -7,5 +7,5 @@ fun _exit(in i32: code)
 
 #[noreturn]
 fun exit(in i32: code) {
-    os::_exit(code)
+    _exit(code)
 }
diff --git a/src/ast/ast.c b/src/ast/ast.c
index 012581f..1306318 100644
--- a/src/ast/ast.c
+++ b/src/ast/ast.c
@@ -5,6 +5,20 @@
 #include <stdio.h>
 #include <sys/log.h>
 
+bool AST_annotation_array_contains_flag(AST_Annotation* haystack, const char* needle) {
+    if (haystack->kind == AnnotationKindArray) {
+        for (guint i = 0; i < haystack->impl.array->len; i++) {
+            AST_Annotation child = g_array_index(haystack->impl.array, AST_Annotation, i);
+
+            if (child.kind == AnnotationKindFlag && strcmp(child.impl.flag, needle) == 0) {
+                return true;
+            }
+        }
+    }
+
+    return false;
+}
+
 struct AST_Node_t* AST_new_node(TokenLocation location,
                                 enum AST_SyntaxElement_t kind,
                                 const char* value) {
@@ -26,6 +40,7 @@ struct AST_Node_t* AST_new_node(TokenLocation location,
     node->kind     = kind;
     node->value    = value;
     node->location = location;
+    node->annotation.kind = AnnotationKindNone;
 
     return node;
 }
diff --git a/src/ast/ast.h b/src/ast/ast.h
index adb71a5..e120cfd 100644
--- a/src/ast/ast.h
+++ b/src/ast/ast.h
@@ -89,6 +89,45 @@ enum AST_SyntaxElement_t {
     AST_ELEMENT_COUNT
 };
 
+typedef enum AST_AnnotationKind_t {
+    AnnotationKindFlag,
+    AnnotationKindVariable,
+    AnnotationKindArray,
+    AnnotationKindNone
+} AST_AnnotationKind;
+
+struct AST_Annotation_t;
+
+typedef enum AST_AnnotationValueKind_t {
+    AnnotationValueKindAnnotation,
+    AnnotationValueKindString,
+    AnnotationValueKindInteger
+} AST_AnnotationValueKind;
+
+typedef struct AST_AnnotationValue_t {
+    AST_AnnotationValueKind kind;
+    union {
+        struct AST_Annotation_t* annotation;
+        char* string;
+        int64_t integer;
+    } impl;
+} AST_AnnotationValue;
+
+typedef struct AST_Annotation_t {
+    AST_AnnotationKind kind;
+    union {
+        // array of annotation values
+        GArray* array;
+        struct {
+            char* name;
+            AST_AnnotationValue value;
+        } variable;
+        char* flag;
+    } impl;
+} AST_Annotation;
+
+bool AST_annotation_array_contains_flag(AST_Annotation*, const char*);
+
 /**
  * @brief A single node which can be joined with other nodes like a graph.
  * Every node can have one ancestor (parent) but multiple (also none) children.
@@ -108,6 +147,8 @@ typedef struct AST_Node_t {
 
     TokenLocation location;
 
+    AST_Annotation annotation;
+
     // children array
     GArray* children;
 } AST_Node;
diff --git a/src/cfg/opt.c b/src/cfg/opt.c
index 97c837a..6a101a6 100644
--- a/src/cfg/opt.c
+++ b/src/cfg/opt.c
@@ -167,7 +167,9 @@ void module_ref_push(ModuleRef* ref, char* name) {
 }
 
 void module_ref_pop(ModuleRef* ref) {
-    g_array_remove_index(ref->module_path, ref->module_path->len - 1);
+    if (ref->module_path->len > 0) {
+        g_array_remove_index(ref->module_path, ref->module_path->len - 1);
+    }
 }
 
 char* module_ref_to_str(ModuleRef* ref) {
diff --git a/src/io/files.c b/src/io/files.c
index aabaef0..12d8478 100644
--- a/src/io/files.c
+++ b/src/io/files.c
@@ -66,7 +66,10 @@ char* module_from_basename(char* path) {
         *dot = '\0';
     }
 
-    return basename;
+    char* cached_module_name = mem_strdup(MemoryNamespaceOpt, basename);
+    g_free(basename);
+
+    return cached_module_name;
 }
 
 void delete_files(ModuleFileStack* stack) {
diff --git a/src/lex/lexer.l b/src/lex/lexer.l
index 8762224..7eaff0b 100644
--- a/src/lex/lexer.l
+++ b/src/lex/lexer.l
@@ -28,7 +28,9 @@
 %%
 "\n"    yyLineNumber++;
 
-//.* ;
+\/\/.* ;
+
+"#" {DEBUG("\"%s\" tokenized with \'#\'", yytext); return('#');};
 
 "::" {return(ModSep);};
 ":" {DEBUG("\"%s\" tokenized with \':\'", yytext); return(':');};
diff --git a/src/set/set.c b/src/set/set.c
index 8cf746c..74cd9e8 100644
--- a/src/set/set.c
+++ b/src/set/set.c
@@ -2648,11 +2648,17 @@ int createFunction(Function* function, AST_NODE_PTR currentNode) {
             return SEMANTIC_ERROR;
     }
 
-    // compose function name by appending parent modules
-    char* modules = module_ref_to_str(currentNode->location.module_ref);
-    char* composed_name = g_strjoin("", modules, "::", function->name, NULL);
-    g_free(modules);
-    function->name = composed_name;
+    if (!(currentNode->annotation.kind == AnnotationKindArray
+        && AST_annotation_array_contains_flag(&currentNode->annotation, "nomangle"))) {
+
+        // compose function name by appending parent modules
+        char* modules = module_ref_to_str(currentNode->location.module_ref);
+        char* composed_name = g_strjoin("", modules, "::", function->name, NULL);
+        char* cached_composed_name = mem_strdup(MemoryNamespaceSet, composed_name);
+        g_free(modules);
+        g_free(composed_name);
+        function->name = cached_composed_name;
+    }
 
     mem_free(functionParameter);
     functionParameter = NULL;
diff --git a/src/yacc/parser.y b/src/yacc/parser.y
index cf83f51..434852e 100644
--- a/src/yacc/parser.y
+++ b/src/yacc/parser.y
@@ -6,6 +6,7 @@
     #include <ast/ast.h>
     #include <sys/col.h>
     #include <io/files.h>
+    #include <mem/cache.h>
     #include <glib.h>
     extern int yylineno;
     extern ModuleFile* current_file;
@@ -26,6 +27,9 @@
 %union {
     char *string;
     AST_NODE_PTR node_ptr;
+    AST_Annotation annotation;
+    AST_AnnotationValue annotationvalue;
+    GArray* array;
 }
 
 %type <node_ptr> operation
@@ -78,7 +82,11 @@
 %type <node_ptr> storage_expr
 %type <node_ptr> returnstmt
 %type <node_ptr> moduleref
-
+%type <node_ptr> callable
+%type <array> annotationlist
+%type <annotationvalue> annotationvalue
+%type <annotation> annotation
+%type <annotation> annotationbind
 
 %token KeyInt
 %token KeyFloat
@@ -155,15 +163,55 @@ program: program programbody {AST_push_node(root, $2);
 
 programbody: moduleimport {$$ = $1;}
        | moduleinclude {$$ = $1;}
-       | fundef{$$ = $1;}
-       | fundecl{$$ = $1;}
-       | procdecl{$$ = $1;}
-       | procdef{$$ = $1;}
+       | callable {$$ = $1;}
        | box{$$ = $1;}
        | definition{$$ = $1;}
        | decl{$$ = $1;}
        | typedef{$$ = $1;};
 
+callable: fundef {$$=$1;}
+        | fundecl {$$=$1;}
+        | procdef {$$=$1;}
+        | procdecl {$$=$1;}
+        | annotationbind callable {
+            $2->annotation = $1;
+            $$ = $2;
+        };
+
+annotationvalue: ValStr { AST_AnnotationValue value;
+                            value.impl.string = $1;
+                            value.kind = AnnotationValueKindString;
+                            $$ = value; }
+            | ValInt { AST_AnnotationValue value;
+                        value.impl.integer = atol($1);
+                        value.kind = AnnotationValueKindInteger;
+                        $$ = value; }
+            | annotation { AST_AnnotationValue value;
+                         value.impl.annotation = mem_clone(MemoryNamespaceAst, &($1), sizeof(AST_Annotation));
+                         value.kind = AnnotationValueKindAnnotation;
+                         $$ = value; };
+
+annotationlist: annotation ',' annotationlist { g_array_append_val($3, $1); $$ = $3; }
+        | annotation { GArray* list = mem_new_g_array(MemoryNamespaceSet, sizeof(AST_Annotation));
+                        g_array_append_val(list, $1);
+                        $$ = list; };
+
+annotation: Ident { AST_Annotation annotation;
+                    annotation.kind = AnnotationKindFlag;
+                    annotation.impl.flag = $1;
+                    $$ = annotation; }
+        | '[' annotationlist ']' { AST_Annotation annotation;
+                                 annotation.kind = AnnotationKindArray;
+                                 annotation.impl.array = $2;
+                                 $$ = annotation; }
+        | Ident '(' annotationvalue ')' { AST_Annotation annotation;
+                                         annotation.kind = AnnotationKindVariable;
+                                         annotation.impl.variable.name = $1;
+                                         annotation.impl.variable.value = $3;
+                                         $$ = annotation; };
+
+annotationbind: '#' annotation { $$ = $2; };
+
 moduleref: Ident {$$ = AST_new_node(new_loc(), AST_Ident, $1);}
         | Ident ModSep moduleref {AST_NODE_PTR modref = AST_new_node(new_loc(), AST_ModuleRef, NULL);
                                    AST_push_node(modref, AST_new_node(new_loc(), AST_Ident, $1));
diff --git a/tests/box/main.gsc b/tests/box/main.gsc
index 9231fa7..07f113a 100644
--- a/tests/box/main.gsc
+++ b/tests/box/main.gsc
@@ -1,6 +1,7 @@
 
 import "std"
 
+#[nomangle]
 fun main() {
     i32: u = 0 as i32
 }