TIP:            289
Title:          Revision of [lrepeat] Argument Order
Version:        $Revision: 1.5 $
Author:         Peter Spjuth <peter.spjuth@space.se>
Author:          <dgp@users.sf.net>
State:          Rejected
Type:           Project
Vote:           Done
Created:        26-Oct-2006
Post-History:   
Keywords:       Tcl
Tcl-Version:    8.5

~ Abstract

This TIP proposes to alter the argument order of '''lrepeat''' to be similar
to '''string repeat'''.

~ Rationale

In [136], lrepeat is defined as:

 > '''lrepeat''' ''number element1'' ?''element2''? ?''element3''? ...

whereas the old string repeat command is:

 > '''string repeat''' ''string number''

This difference between similar commands is bound to cause confusion.
Consistency is good.

~ Specification

Change lrepeat's argument order to:

 > '''lrepeat''' ''element1'' ?''element2''? ?''element3''? ... '''number'''

~ Examples:

| lrepeat 0 100                - returns list of 100 zeros
| lrepeat [lrepeat 0 100] 100  - returns 100x100 matrix (list of lists) of zeros
| lrepeat a b c 3              - returns nine-element list {a b c a b c a b c}
| lrepeat a b c 1              - identical to [list a b c]

~ Discussion:

DGP: The main feature that appears to get lost in this change is the
ability to redirect aliases or subcommands of ensembles to '''lrepeat'''
calls with the number of repetitions already filled in.

PS: On the other hand, you get the ability to redirect aliases or
subcommands of ensembles to '''lrepeat''' calls with the elements already
filled in.

DGP: I skimmed the old TIP 136 messages in the TCLCORE archives. One
thing to note is that the existing '''lrepeat''' syntax in 8.5a5 was
chosen in part to be consistent with the existing '''struct::list
repeat''' syntax in the struct::list package.

DGP: I think it's fair to say that given a complete "do-over"
more of us would opt to change '''string repeat''' to agree
with '''lrepeat''' and '''struct::list repeat''' than the other
way around.

~ Copyright

This document has been placed in the public domain.
