'''Case Insensitive TCL commands'''

Some days back I faced an issue with writing case insensitive procedure names.
i.e 

    proc abc {} {
        puts "Called function abc() .."
    }

This should work with other 7 variants ABC, abC, aBc, aBC, Abc, AbC, aBc.

The solution to this could be to use the ''unknown'' function in TCL.

# define the original command name list.
    set orig_cmd_names [list abc]

# Rename the original ''unknown'' to ''unknown_orig''
    rename unknown unknown_orig

# Define a customized unknown procedure.
    proc unknown {args} {
        set cmd [lindex $args 0]
        global orig_cmd_names
        foreach oCmd $orig_cmd_names {
            if {[regexp -nocase ^($oCmd)$ $cmd]} {
                # Found the command .. !, now execute it in global scope
                set result [uplevel #0 $oCmd [lrange $args 1 end]]
                return -code ok $result
            }
        }
        # Not found .. :-(, call the base unknown function.
        unknown_orig $args
    }

    %abC
    Called function abc() ..
    %Abc
    Called function abc() ..

[MG] would recommend using [string equal] instead of [regexp] to compare the strings, otherwise you could get inaccurate matches when command names contain chars with special meaning for regexp (proc a..z).

[MJ] would recommend to install [interp alias]es for the other capitalisations as well so subsequent calls to the different capitalisation don't invoke unknown. Executing the command in global scope is probably an error anyway. It will fail nicely if the original command uses [uplevel] or [upvar] for instance.