## Copyright (C) 2006 Bill Denney

##

## This file is part of Octave.

##

## Octave is free software; you can redistribute it and/or modify it

## under the terms of the GNU General Public License as published by

## the Free Software Foundation; either version 2, or (at your option)

## any later version.

##

## Octave is distributed in the hope that it will be useful, but

## WITHOUT ANY WARRANTY; without even the implied warranty of

## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

## General Public License for more details.

##

## You should have received a copy of the GNU General Public License

## along with Octave; see the file COPYING.  If not, write to the Free

## Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

## 02110-1301, USA.



## -*- texinfo -*-

## @deftypefn {Function File} @var{string} = regexprep(@var{string}, @var{regex}, @var{repstr}, @var{options})

## Replace occurances of @var{repre} in string with @var{repstr}.

##

## @var{options} may be one or more of

## @table @samp

## @item N

## Replace the Nth match of the regexp

##

## @item once

## Replace only the first occurance of the regexp in the result. (The

## same as @var{N} = 1.)

##

## @item warnings

## This option is ignored, but it does not give an error.

## @end table

## @seealso{regexp}

## @end deftypefn



function string = regexprep(string, repre, repstr, varargin)



  ## Parse input arguements



  n = -1;

  for i = 1:length(varargin)

    if isnumeric(varargin{i})

      n = assignn(n, varargin{i});

    elseif strcmpi(varargin{i}, "once")

      n = assignn(n, 1);

    elseif strcmpi(varargin{i}, "warnings") ## for compatability

    else

      ## I could do more type checking here, but it will just throw an

      ## error for things like cells or other types, and that's OK by

      ## me.

      error("regexprep: Unrecognised option '%s'", varargin{i});

    endif

  endfor



  [st, en] = regexp(string, repre);

  if (n > 0)

    if (length(st) >= n)

      st = st(n);

    else

      warning("regexprep: fewer matches than N, original string returned");

      st = [];

    endif

  endif



  for i = length(st):-1:1

    string = [string(1:st(i)-1) repstr string(en(i)+1:length(string))];

  endfor



endfunction



function n = assignn(n, newn)



  if (newn < 0)

    warning("regexprep: negative value for N given; all matches will be replaced");

  endif



  if (n < 0)

    n = newn;

  else

    warning("regexprep: conflicting options given for N");

  endif



endfunction