Add type_name function to query the type of a value

doc/function/index.txt

@@ -11,6 +11,7 @@ These functions are built into the program, other [[type:function]]s can be defi
 | [[fun:to_color]]		Convert any value to a [[type:color]]
 | [[fun:to_image]]		Convert any value to an [[type:image]]
 | [[fun:to_date]]		Convert any value to a [[type:date]]
+| [[fun:type_name]]		Get the type of a value
 	
 ! Numbers			<<<
 | [[fun:abs]]			Absolute value

doc/function/type_name.txt

@@ -0,0 +1,17 @@
+Function: type_name
+
+DOC_MSE_VERSION: since 2.0.2
+
+--Usage--
+> type_name(any_value)
+
+Return the type of the given value as a string.
+Note that type names are localized, so they should not be compared to a fixed string.
+
+--Parameters--
+! Parameter	Type			Description
+| @input@	''any type''		Value to determine the type of.
+
+--Examples--
+> type_name("hello") == "string"
+> type_name(1)       == "integer number"

src/script/functions/basic.cpp

@@ -220,6 +220,11 @@ SCRIPT_FUNCTION(to_code) {
   SCRIPT_RETURN(input->toCode());
 }
 
+SCRIPT_FUNCTION(type_name) {
+  SCRIPT_PARAM_C(ScriptValueP, input);
+  SCRIPT_RETURN(input->typeName());
+}
+
 // ----------------------------------------------------------------------------- : Math
 
 SCRIPT_FUNCTION(abs) {
@@ -718,6 +723,7 @@ void init_script_basic_functions(Context& ctx) {
   ctx.setVariable(_("to color"),             script_to_color);
   ctx.setVariable(_("to date"),              script_to_date);
   ctx.setVariable(_("to code"),              script_to_code);
+  ctx.setVariable(_("type name"),            script_type_name);
   // math
   ctx.setVariable(_("abs"),                  script_abs);
   ctx.setVariable(_("random real"),          script_random_real);