TIP #151: Remove -e: Command Line Option from tclsh and wish
_____________________________________________________________________________
TIP:	151
Title:	Remove -e: Command Line Option from tclsh and wish
Version:	$Revision: 1.7 $
Authors:	Don Porter <dgp@users.sourceforge.net>
	Don Porter <dgp@users.sf.net>
	Donal K. Fellows <donal.k.fellows@man.ac.uk>
State:	Final
Type:	Project
Tcl-Version:	8.5
Vote:	Done
Created:	Fri Aug 22 00:00:00 UTC 2003
Abstract
This TIP proposes removal of the -e: command line option to tclsh and wish that was Accepted as part of [137].
Background
[137] was Accepted today. However, there were a few NO votes objecting to the new -e: form of the -encoding command line option for specifying the encoding of a startup script to tclsh and wish. Those voting NO only objected to that part of [137] while supporting the rest as a solid proposal that will improve Tcl. Among those voting YES, no one explicitly embraced the -e: command line option as something they required. Some voting YES opined that the -e: option was a wart that could be fixed later.
Based on those comments, [137] would have been better had the -e: form of the command line option not been part of the proposal. This TIP proposes nothing more than removing Acceptance of the -e: form of the -encoding command line option.
Without the controversial -e: proposal, I believe [137] would have had unanimous approval.
Rationale
The use of -e: as a command line option to tclsh or wish suffers when compared with the perl program. The perl -e option for evaluation of a Perl script provided on the command line is very well known, and it's a mistake to add something to tclsh that looks similar, but is in fact very different.
[137] proposed both -encoding and the -e: form. There's really no need to add multiple ways to do the same thing.
The Rationale in [137] for the -e: form is solely to support the 32-character limit in some Unices for their #! lines. However, the -e: form does not really solve that problem. For example:
 #!/usr/local/bin/tclsh8.5 -e:iso8859-15 
 12345678901234567890123456789012
Here we see that we still run afoul of the 32-character limit when tclsh is installed in the default location. Even longer encoding names exist which magnify the problem, and altering the installation location will not necessarily help:
 #!/usr/bin/tclsh8.5 -e:iso8859-15 
 12345678901234567890123456789012
(This is actually an insidious failure mode in that it leads to the script being sourced with a valid but incorrect encoding.)
Conversely, we already have an effective general workaround for the 32-character limit problem:
 #!/bin/sh
 # \par exec tclsh -encoding iso8859-15 "$0" $1+"$@"
So, -e: doesn't solve a problem we don't really have, and it's controverisal. We should remove it.
Proposal
Remove (Acceptance of) the -e: set of command line options to the programs tclsh and wish.
Compatibility
Since no version of Tcl or Tk has been released supporting the -e: command line option, there are no compatibility issues to resolve.
Copyright
This document is placed in the public domain.
_____________________________________________________________________________
Colophon
TIP AutoGenerator - written by Donal K. Fellows