TIP 334: Make 'lrepeat' Accept Zero as a Count

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by Aug 21.
Author:		Michael Thomas Greer <michael.thomas.greer@verizon.net>
State:		Withdrawn
Type:		Project
Tcl-Version:	8.6
Vote:		Pending
Created:	13-Oct-2008
Post-History:	
Keywords:	empty list

Abstract

Following on from [323], the lrepeat command should also act gracefully when a repeat count of zero is used, as an empty list is still a valid list.

Rationale

A list of zero items is a valid, empty list. In my own experience (I cannot speak for others'), generating a list of N identical elements is more often an algorithmic expression than a literal shorthand, and often enough an empty list is the correct result. All other core list commands properly handle empty lists; but lrepeat complains when given a count of zero repetitions, requiring additional code to handle this (doubly) exceptional condition.

Proposal

The lrepeat command should be changed so that when it's first, count, argument is zero, it returns an empty list.

Copyright

This document has been placed in the public domain.

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