incr Tcl (commonly stylised as ''
ncr Tcl NCR may refer to:
* NCR Corporation, formerly National Cash Register
* "No carbon required" carbonless copy paper
* A Nature Conservation Review, UK book
* Naval Construction Regiment of US Navy Seabees
* New Carrollton station Amtrak code
* Not c ...
/nowiki>'', and often abbreviated to ''itcl'') is a set of object-oriented extensions for the Tcl programming language. It is widely used among the Tcl community, and is generally regarded as