[TCLCORE] TIP #358: Suppress Empty List Element Generation from the Split Command

[George P. <pe...@ii...>]

 TIP #358: SUPPRESS EMPTY LIST ELEMENT GENERATION FROM THE SPLIT COMMAND 
=========================================================================
 Version:      $Revision: 1.2 $
 Author:       George Petasis <petasis_at_iit.demokritos.gr>
 State:        Draft
 Type:         Project
 Tcl-Version:  8.7
 Vote:         Pending
 Created:      Sunday, 04 October 2009
 URL:          http://purl.org/tcl/tip/358.html
 WebEdit:      http://purl.org/tcl/tip/edit/358
 Post-History: 

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 ABSTRACT 
==========

 The *split* command will create empty list elements when adjacent split 
 characters are found in the input. In some cases these empty list 
 elements are not desired, so this TIP proposes a new switch to disable 
 their generation. 

 RATIONALE 
===========

 The idea for this TIP came from a discussion in comp.lang.tcl: 
 [<URL:http://groups.google.gr/group/comp.lang.tcl/browse_thread/thread/8d46b0f10e7a5750/d7844cc739aa4310>] 
 and the (non obvious) suggestions on how tokens can be extracted from a 
 string can be performed efficiently. 

 It should be noted that this will allow the *split* command to be used 
 in a fashion that is very similar to how splitting works in many other 
 languages (e.g., Perl, awk, Unix shells). 

 SPECIFICATION 
===============

 This TIP proposes a new optional switch (*-noemptyelements*) to the 
 *split* command: 

       *split -noemptyelements* /string/ ?/splitChars/? 

 If this option is present, then *split* will not produce an empty list 
 element when the /string/ contains adjacent characters that are present 
 in /splitChars/. 

 REFERENCE IMPLEMENTATION 
==========================

 Currently there is no patch, but it should be quite easy to implement 
 this. 

 COPYRIGHT 
===========

 This document has been placed in the public domain. 

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