Feature for fast trial of scripting expressions

Please add a dialog box for fast trialling scripting expressions, having a Format String input control, live-updated output text, and a Cancel button - that's all.

I currently use Tag - Filename when possible... which is not always because but the output is not the true script output - instead it the script output processed through $validate.

Thanks.

Same request there ...
/t/8723/1

DD.20090808.1858.CEST