MiHa 2015-05:

Online-IDEs / -Compilers / -Interpreters are websites where you can enter/paste some sourcecode, and have it executed.
They commonly offer the functionality to give the user a short URL for the entered code, like http://pastebin.com/.

Smallish programs can be run that way, typically no more than a few kb of code. Same for input-data.

Some Online-IDEs are dedicated to only one language:

• http://www.lua.org/demo.html - Lua
• http://play.golang.org - Go
• https://jsfiddle.net - JavaScript, Ajax, etc.

These Online-IDEs have support for tcl:

• http://codepad.org/
• http://ideone.com/
• http://www.tutorialspoint.com/execute_tcl_online.php
• http://rextester.com/l/tcl_online_compiler
• https://tio.run/#tcl — seems to be online since 2017/04/19, as the info from https://chat.stackexchange.com/search?q=tcl&room=44255 , which also shows it has the Trf package installed.
• https://www.jdoodle.com/execute-tcl-online
• ...

Some others are listed at Tcl Web Resources .. these pages might benefit from being merged.

---