/*

Copyright (C) 2005, 2006, 2007 David Bateman
Copyright (C) 2002, 2003, 2004, 2005 Paul Kienzle

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 3 of the License, 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, see
<http://www.gnu.org/licenses/>.

*/

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <algorithm>
#include <sstream>

#include "defun-dld.h"
#include "error.h"
#include "gripes.h"
#include "oct-obj.h"
#include "utils.h"

#include "Cell.h"
#include "oct-map.h"
#include "str-vec.h"
#include "quit.h"
#include "parse.h"

#if defined (HAVE_PCRE)
#include <pcre.h>
#elif defined (HAVE_REGEX)
#if defined (__MINGW32__)
#define __restrict
#endif
#if defined (HAVE_SYS_TYPES_H)
#include <sys/types.h>
#endif
#include <regex.h>
#endif

// The regexp is constructed as a linked list to avoid resizing the
// return values in arrays at each new match.

// FIXME don't bother collecting and composing return values the user
// doesn't want.

class regexp_elem
{
public:
  regexp_elem (const string_vector& _named_token, const Cell& _t, 
	       const std::string& _m, const Matrix& _te, double _s, 
	       double _e) :
    named_token (_named_token), t (_t), m (_m), te (_te), s (_s), e (_e) { }

  regexp_elem (const regexp_elem &a) : named_token (a.named_token), t (a.t), 
				       m (a.m), te (a.te), s (a.s), e (a.e)
				       { }

  string_vector named_token;
  Cell t;
  std::string m;
  Matrix te;
  double s;
  double e;
};

typedef std::list<regexp_elem>::const_iterator const_iterator;

static int
octregexp_list (const octave_value_list &args, const std::string &nm, 
		bool case_insensitive, std::list<regexp_elem> &lst, 
		string_vector &named, int &nopts)
{
  int sz = 0;
#if defined (HAVE_REGEX) || defined (HAVE_PCRE) 
  int nargin = args.length();
  bool once = false;
  bool lineanchors = false;
  bool dotexceptnewline = false;
  bool freespacing = false;

  nopts = nargin - 2;

  std::string buffer = args(0).string_value ();
  if (error_state)
    {
      gripe_wrong_type_arg (nm.c_str(), args(0));
      return 0;
    }

  std::string pattern = args(1).string_value ();
  if (error_state)
    {
      gripe_wrong_type_arg (nm.c_str(), args(1));
      return 0;
    }

  for (int i = 2; i < nargin; i++)
    {
      std::string str = args(i).string_value();
      if (error_state)
	{
	  error ("%s: optional arguments must be strings", nm.c_str());
	  break;
	}
      std::transform (str.begin (), str.end (), str.begin (), tolower);
      if (str.find("once", 0) == 0)
	{
	  once = true;
	  nopts--;
	}
      else if (str.find("matchcase", 0) == 0)
	{
	  case_insensitive = false;
	  nopts--;
	}
      else if (str.find("ignorecase", 0) == 0)
	{
	  case_insensitive = true;
	  nopts--;
	}
      else if (str.find("dotall", 0) == 0)
	{
	  dotexceptnewline = false;
	  nopts--;
	}
      else if (str.find("stringanchors", 0) == 0)
	{
	  lineanchors = false;
	  nopts--;
	}
      else if (str.find("literalspacing", 0) == 0)
	{
	  freespacing = false;
	  nopts--;
	}
#if HAVE_PCRE
      // Only accept these options with pcre
      else if (str.find("dotexceptnewline", 0) == 0)
	{
	  dotexceptnewline = true;
	  nopts--;
	}
      else if (str.find("lineanchors", 0) == 0)
	{
	  lineanchors = true;
	  nopts--;
	}
      else if (str.find("freespacing", 0) == 0)
	{
	  freespacing = true;
	  nopts--;
	}
      else if (str.find("start", 0) && str.find("end", 0) &&
	       str.find("tokenextents", 0) && str.find("match", 0) &&
	       str.find("tokens", 0) && str.find("names", 0))
	error ("%s: unrecognized option", nm.c_str());
#else
      else if (str.find("names", 0) == 0 ||
	       str.find("dotexceptnewline", 0) == 0 ||
	       str.find("lineanchors", 0) == 0 ||
	       str.find("freespacing", 0) == 0)
       error ("%s: %s not implemented in this version", str.c_str(), nm.c_str());
      else if (str.find("start", 0) && str.find("end", 0) &&
	       str.find("tokenextents", 0) && str.find("match", 0) &&
	       str.find("tokens", 0))
	error ("%s: unrecognized option", nm.c_str());
#endif
    }

  if (!error_state)
    {
      Cell t;
      std::string m;
      double s, e;

      // named tokens "(?<name>...)" are only treated with PCRE not regex.
#if HAVE_PCRE
      // The syntax of named tokens in pcre is "(?P<name>...)" while we need
      // a syntax "(?<name>...)", so fix that here. Also an expression like
      // "(?<first>\w+)\s+(?<last>\w+)|(?<last>\w+),\s+(?<first>\w+)" should
      // be perfectly legal, while pcre does not allow the same named token
      // name on both sides of the alternative. Also fix that here by replacing
      // name tokens by dummy names, and dealing with the dummy names later.
      
      size_t pos = 0;
      size_t new_pos;
      int nnames = 0;
      int inames = 0;
      std::ostringstream buf;
      Array<int> named_idx;

      while ((new_pos = pattern.find ("(?<",pos)) != NPOS)
	{
	  size_t tmp_pos = pattern.find_first_of ('>',new_pos);

	  if (tmp_pos == NPOS)
	    {
	      error ("syntax error in pattern");
	      break;
	    }

	  std::string tmp_name = pattern.substr(new_pos+3,tmp_pos-new_pos-3);
	  bool found = false;

	  for (int i = 0; i < nnames; i++)
	    if (named(i) == tmp_name)
	      {
		named_idx.resize(inames+1);
		named_idx(inames) = i;
		found = true;
		break;
	      }
	  if (! found)
	    {
	      named_idx.resize(inames+1);
	      named_idx(inames) = nnames;
	      named.append(tmp_name);
	      nnames++;
	    }

	  if (new_pos - pos > 0)
	    buf << pattern.substr(pos,new_pos-pos);
	  if (inames < 10)
	    buf << "(?P<n00" << inames++;
	  else if (inames < 100)
	    buf << "(?P<n0" << inames++;
	  else
	    buf << "(?P<n" << inames++;
	  pos = tmp_pos;
	}

      buf << pattern.substr(pos);

      if (error_state)
	return 0;

      // Compile expression
      pcre *re;
      const char *err;
      int erroffset;
      std::string buf_str = buf.str ();
      re = pcre_compile (buf_str.c_str (),
			 (case_insensitive ? PCRE_CASELESS : 0) |
			 (dotexceptnewline ? 0 : PCRE_DOTALL) |
			 (lineanchors ? PCRE_MULTILINE : 0) |
			 (freespacing ? PCRE_EXTENDED : 0),
			 &err, &erroffset, 0);
    
      if (re == 0) {
	error("%s: %s at position %d of expression", nm.c_str(), 
	      err, erroffset);
	return 0;
      }

      int subpatterns;
      int namecount;
      int nameentrysize;
      char *nametable;
      int idx = 0;

      pcre_fullinfo(re, 0, PCRE_INFO_CAPTURECOUNT,  &subpatterns);
      pcre_fullinfo(re, 0, PCRE_INFO_NAMECOUNT, &namecount);
      pcre_fullinfo(re, 0, PCRE_INFO_NAMEENTRYSIZE, &nameentrysize);
      pcre_fullinfo(re, 0, PCRE_INFO_NAMETABLE, &nametable);

      OCTAVE_LOCAL_BUFFER(int, ovector, (subpatterns+1)*3);
      OCTAVE_LOCAL_BUFFER(int, nidx, namecount);

      for (int i = 0; i < namecount; i++)
	{
	  // Index of subpattern in first two bytes MSB first of name.
	  // Extract index.
	  nidx[i] = (static_cast<int>(nametable[i*nameentrysize])) << 8 |
	    static_cast<int>(nametable[i*nameentrysize+1]);
	}

      while(true)
	{
	  OCTAVE_QUIT;

	  int matches = pcre_exec(re, 0, buffer.c_str(), 
				  buffer.length(), idx, 
				  (idx ? PCRE_NOTBOL : 0),
				  ovector, (subpatterns+1)*3);

	  if (matches < 0 && matches != PCRE_ERROR_NOMATCH)
	    {
	      error ("%s: internal error calling pcre_exec", nm.c_str());
	      pcre_free(re);
	      return 0;
	    }
	  else if (matches == PCRE_ERROR_NOMATCH)
	    break;
	  else if (ovector[1] <= ovector[0])
	    break;
	  else
	    {
	      int pos_match = 0;
	      Matrix te(matches-1,2);
	      for (int i = 1; i < matches; i++)
		{
		  if (ovector[2*i] >= 0 && ovector[2*i+1] > 0)
		    {
		      te(pos_match,0) = double (ovector[2*i]+1);
		      te(pos_match++,1) = double (ovector[2*i+1]);
		    }
		}
	      te.resize(pos_match,2);
	      s = double (ovector[0]+1);
	      e = double (ovector[1]);

	      const char **listptr;
	      int status = pcre_get_substring_list(buffer.c_str(), ovector, 
						   matches, &listptr);

	      if (status == PCRE_ERROR_NOMEMORY) {
		error("%s: cannot allocate memory in pcre_get_substring_list",
		      nm.c_str());
		pcre_free(re);
		return 0;
	      }

	      Cell cell_t (dim_vector(1,pos_match));
	      pos_match = 0;
	      for (int i = 1; i < matches; i++)
		if (ovector[2*i] >= 0 && ovector[2*i+1] > 0)
		  cell_t(pos_match++) = std::string(*(listptr+i));

	      m =  std::string(*listptr);
	      t = cell_t;

	      string_vector named_tokens(nnames);
	      if (namecount > 0)
		for (int i = 1; i < matches; i++)
		  {
		    if (ovector[2*i] >= 0 && ovector[2*i+1] > 0)	
		      {
			named_tokens(named_idx(i-1)) = 
			  std::string(*(listptr+nidx[i-1]));
		      }
		  }

	      pcre_free_substring_list(listptr);

	      regexp_elem new_elem (named_tokens, t, m, te, s, e);
	      lst.push_back (new_elem);
	      idx = ovector[1];
	      sz++;

	      if (once)
		break;

	    }
	}

      pcre_free(re);
#else
      regex_t compiled;
      int err=regcomp(&compiled, pattern.c_str(), REG_EXTENDED | 
		      (case_insensitive ? REG_ICASE : 0));
      if (err)
	{
	  int len = regerror(err, &compiled, 0, 0);
	  OCTAVE_LOCAL_BUFFER (char, errmsg, len);
	  regerror(err, &compiled, errmsg, len);
	  error("%s: %s in pattern (%s)", nm.c_str(), errmsg, 
		pattern.c_str());
	  regfree(&compiled);
	  return 0;
	}

      int subexpr = 1;
      int idx = 0;
      for (unsigned int i=0; i < pattern.length(); i++)
	  subexpr += ( pattern[i] == '(' ? 1 : 0 );
      OCTAVE_LOCAL_BUFFER (regmatch_t, match, subexpr );

      while(true)
	{
	  OCTAVE_QUIT; 

	  if (regexec(&compiled, buffer.c_str() + idx, subexpr, 
		      match, (idx ? REG_NOTBOL : 0)) == 0) 
	    {
	      // Count actual matches
	      int matches = 0;
	      while (matches < subexpr && match[matches].rm_so >= 0) 
		matches++;

	      s = double (match[0].rm_so+1+idx);
	      e = double (match[0].rm_eo+idx);
	      Matrix te(matches-1,2);
	      for (int i = 1; i < matches; i++)
		{
		  te(i-1,0) = double (match[i].rm_so+1+idx);
		  te(i-1,1) = double (match[i].rm_eo+idx);
		}

	      m =  buffer.substr (match[0].rm_so+idx, 
					 match[0].rm_eo-match[0].rm_so);

	      Cell cell_t (dim_vector(1,matches-1));
	      for (int i = 1; i < matches; i++)
		cell_t(i-1) = buffer.substr (match[i].rm_so+idx, 
					     match[i].rm_eo-match[i].rm_so);
	      t = cell_t;

	      idx += match[0].rm_eo;

	      string_vector sv;
	      regexp_elem new_elem (sv, t, m, te, s, e);
	      lst.push_back (new_elem);
	      sz++;

	      if (once)
		break;
	    }
	  else
	    break;
	}
      regfree(&compiled);
#endif
    }
#else
  error ("%s: not available in this version of Octave", nm.c_str());
#endif
  return sz;
}

static octave_value_list
octregexp (const octave_value_list &args, int nargout, const std::string &nm,
	   bool case_insensitive)
{
  octave_value_list retval;
  int nargin = args.length();
  std::list<regexp_elem> lst;
  string_vector named;
  int nopts;
  int sz = octregexp_list (args, nm, case_insensitive, lst, named, nopts);

  if (! error_state)
    {
      // Converted the linked list in the correct form for the return values

      octave_idx_type i = 0;
#ifdef HAVE_PCRE
      Octave_map nmap;
      if (sz == 1)
	{
	  for (int j = 0; j < named.length(); j++)
	    nmap.assign (named(j), lst.begin()->named_token(j));
	  retval(5) = nmap;
	}
      else
	{
	  for (int j = 0; j < named.length (); j++)
	    {
	      i = 0;
	      Cell tmp(dim_vector (1, sz));
	      for (const_iterator p = lst.begin(); p != lst.end(); p++)
		tmp(i++) = p->named_token(j);
	      nmap.assign (named(j), octave_value (tmp));
	    }
	  retval(5) = nmap;
	}
#else
      retval(5) = Octave_map();
#endif

      Cell t (dim_vector(1, sz));
      i = 0;
      for (const_iterator p = lst.begin(); p != lst.end(); p++)
	t(i++) = p->t;
      retval(4) = t;

      Cell m (dim_vector(1, sz));
      i = 0;
      for (const_iterator p = lst.begin(); p != lst.end(); p++)
	m(i++) = p->m;
      retval(3) = m;


      Cell te (dim_vector(1, sz));
      i = 0;
      for (const_iterator p = lst.begin(); p != lst.end(); p++)
	te(i++) = p->te;
      retval(2) = te;

      NDArray e (dim_vector(1, sz));
      i = 0;
      for (const_iterator p = lst.begin(); p != lst.end(); p++)
	e(i++) = p->e;
      retval(1) = e;

      NDArray s (dim_vector(1, sz));
      i = 0;
      for (const_iterator p = lst.begin(); p != lst.end(); p++)
	s(i++) = p->s;
      retval(0) = s;

      // Alter the order of the output arguments
      if (nopts > 0)
	{
	  int n = 0;
	  octave_value_list new_retval;
	  new_retval.resize(nargout);

	  OCTAVE_LOCAL_BUFFER (int, arg_used, 6);
	  for (int j = 0; j < 6; j++)
	    arg_used[j] = false;
	  
	  for (int j = 2; j < nargin; j++)
	    {
	      int k = 0;
	      std::string str = args(j).string_value();
	      std::transform (str.begin (), str.end (), str.begin (), tolower);
	      if (str.find("once", 0) == 0
		  || str.find("stringanchors", 0) == 0
		  || str.find("lineanchors", 0) == 0
		  || str.find("matchcase", 0) == 0
		  || str.find("ignorecase", 0) == 0
		  || str.find("dotall", 0) == 0
		  || str.find("dotexceptnewline", 0) == 0
		  || str.find("literalspacing", 0) == 0
		  || str.find("freespacing", 0) == 0
	      )
		continue;
	      else if (str.find("start", 0) == 0)
		k = 0;
	      else if (str.find("end", 0) == 0)
		k = 1;
	      else if (str.find("tokenextents", 0) == 0)
		k = 2;
	      else if (str.find("match", 0) == 0)
		k = 3;
	      else if (str.find("tokens", 0) == 0)
		k = 4;
	      else if (str.find("names", 0) == 0)
		k = 5;

	      new_retval(n++) = retval(k);
	      arg_used[k] = true;

	      if (n == nargout)
		break;
	    }

	  // Fill in the rest of the arguments
	  if (n < nargout)
	    {
	      for (int j = 0; j < 6; j++)
		{
		  if (! arg_used[j])
		    new_retval(n++) = retval(j);
		}
	    }

	  retval = new_retval;
	}
    }

  return retval;
}

static octave_value_list
octcellregexp (const octave_value_list &args, int nargout, const std::string &nm,
	       bool case_insensitive)
{
  octave_value_list retval;

  if (args(0).is_cell())
    {
      OCTAVE_LOCAL_BUFFER (Cell, newretval, nargout);
      octave_value_list new_args = args;
      Cell cellstr = args(0).cell_value();
      if (args(1).is_cell())
	{
	  Cell cellpat = args(1).cell_value();

	  if (cellpat.numel() == 1)
	    {
	      for (int j = 0; j < nargout; j++)
		newretval[j].resize(cellstr.dims());

	      new_args(1) = cellpat(0);

	      for (octave_idx_type i = 0; i < cellstr.numel (); i++)
		{
		  new_args(0) = cellstr(i);
		  octave_value_list tmp = octregexp (new_args, nargout, nm, 
						     case_insensitive);

		  if (error_state)
		    break;

		  for (int j = 0; j < nargout; j++)
		    newretval[j](i) = tmp(j);
		}
	    }
	  else if (cellstr.numel() == 1)
	    {
	      for (int j = 0; j < nargout; j++)
		newretval[j].resize(cellpat.dims());

	      new_args(0) = cellstr(0);

	      for (octave_idx_type i = 0; i < cellpat.numel (); i++)
		{
		  new_args(1) = cellpat(i);
		  octave_value_list tmp = octregexp (new_args, nargout, nm, 
						     case_insensitive);

		  if (error_state)
		    break;

		  for (int j = 0; j < nargout; j++)
		    newretval[j](i) = tmp(j);
		}
	    }
	  else if (cellstr.numel() == cellpat.numel())
	    {

	      if (cellstr.dims() != cellpat.dims())
		error ("%s: Inconsistent cell array dimensions", nm.c_str());
	      else
		{
		  for (int j = 0; j < nargout; j++)
		    newretval[j].resize(cellstr.dims());

		  for (octave_idx_type i = 0; i < cellstr.numel (); i++)
		    {
		      new_args(0) = cellstr(i);
		      new_args(1) = cellpat(i);

		      octave_value_list tmp = octregexp (new_args, nargout, nm, 
							 case_insensitive);

		      if (error_state)
			break;

		      for (int j = 0; j < nargout; j++)
			newretval[j](i) = tmp(j);
		    }
		}
	    }
	  else
	    error ("regexp: cell array arguments must be scalar or equal size");
	}
      else
	{
	  for (int j = 0; j < nargout; j++)
	    newretval[j].resize(cellstr.dims());

	  for (octave_idx_type i = 0; i < cellstr.numel (); i++)
	    {
	      new_args(0) = cellstr(i);
	      octave_value_list tmp = octregexp (new_args, nargout, nm, case_insensitive);

	      if (error_state)
		break;

	      for (int j = 0; j < nargout; j++)
		newretval[j](i) = tmp(j);
	    }
	}

      if (!error_state)
	for (int j = 0; j < nargout; j++)
	  retval(j) = octave_value (newretval[j]);
    }
  else if (args(1).is_cell())
    {
      OCTAVE_LOCAL_BUFFER (Cell, newretval, nargout);
      octave_value_list new_args = args;
      Cell cellpat = args(1).cell_value();

      for (int j = 0; j < nargout; j++)
	newretval[j].resize(cellpat.dims());

      for (octave_idx_type i = 0; i < cellpat.numel (); i++)
	{
	  new_args(1) = cellpat(i);
	  octave_value_list tmp = octregexp (new_args, nargout, nm, case_insensitive);

	  if (error_state)
	    break;

	  for (int j = 0; j < nargout; j++)
	    newretval[j](i) = tmp(j);
	}

      if (!error_state)
	for (int j = 0; j < nargout; j++)
	  retval(j) = octave_value (newretval[j]);
    }
  else
    retval = octregexp (args, nargout, nm, case_insensitive);

  return retval;

}

DEFUN_DLD (regexp, args, nargout,
  "-*- texinfo -*-\n\
@deftypefn {Loadable Function} {[@var{s}, @var{e}, @var{te}, @var{m}, @var{t}, @var{nm}] =} regexp (@var{str}, @var{pat})\n\
@deftypefnx {Loadable Function} {[@dots{}] =} regexp (@var{str}, @var{pat}, @var{opts}, @dots{})\n\
\n\
Regular expression string matching. Matches @var{pat} in @var{str} and\n\
returns the position and matching substrings or empty values if there are\n\
none.\n\
\n\
The matched pattern @var{pat} can include any of the standard regex\n\
operators, including:\n\
\n\
@table @code\n\
@item .\n\
Match any character\n\
@item * + ? @{@}\n\
Repetition operators, representing\n\
@table @code\n\
@item *\n\
Match zero or more times\n\
@item +\n\
Match one or more times\n\
@item ?\n\
Match zero or one times\n\
@item @{@}\n\
Match range operator, which is of the form @code{@{@var{n}@}} to match exactly\n\
@var{n} times, @code{@{@var{m},@}} to match @var{m} or more times,\n\
@code{@{@var{m},@var{n}@}} to match between @var{m} and @var{n} times.\n\
@end table\n\
@item [@dots{}] [^@dots{}]\n\
List operators, where for example @code{[ab]c} matches @code{ac} and @code{bc}\n\
@item ()\n\
Grouping operator\n\
@item |\n\
Alternation operator. Match one of a choice of regular expressions. The\n\
alternatives must be delimited by the grouping operator @code{()} above\n\
@item ^ $\n\
Anchoring operator. @code{^} matches the start of the string @var{str} and\n\
@code{$} the end\n\
@end table\n\
\n\
In addition the following escaped characters have special meaning. It should\n\
be noted that it is recommended to quote @var{pat} in single quotes rather\n\
than double quotes, to avoid the escape sequences being interpreted by octave\n\
before being passed to @code{regexp}.\n\
\n\
@table @code\n\
@item \\b\n\
Match a word boundary\n\
@item \\B\n\
Match within a word\n\
@item \\w\n\
Matches any word character\n\
@item \\W\n\
Matches any non word character\n\
@item \\<\n\
Matches the beginning of a word\n\
@item \\>\n\
Matches the end of a word\n\
@item \\s\n\
Matches any whitespace character\n\
@item \\S\n\
Matches any non whitespace character\n\
@item \\d\n\
Matches any digit\n\
@item \\D\n\
Matches any non-digit\n\
@end table\n\
\n\
The outputs of @code{regexp} by default are in the order as given below\n\
\n\
@table @asis\n\
@item @var{s}\n\
The start indices of each of the matching substrings\n\
\n\
@item @var{e}\n\
The end indices of each matching substring\n\
\n\
@item @var{te}\n\
The extents of each of the matched token surrounded by @code{(@dots{})} in\n\
@var{pat}.\n\
\n\
@item @var{m}\n\
A cell array of the text of each match.\n\
\n\
@item @var{t}\n\
A cell array of the text of each token matched.\n\
\n\
@item @var{nm}\n\
A structure containing the text of each matched named token, with the name\n\
being used as the fieldname. A named token is denoted as\n\
@code{(?<name>@dots{})}\n\
@end table\n\
\n\
Particular output arguments or the order of the output arguments can be\n\
selected by additional @var{opts} arguments. These are strings and the\n\
correspondence between the output arguments and the optional argument\n\
are\n\
\n\
@multitable @columnfractions 0.2 0.3 0.3 0.2\n\
@item @tab 'start'        @tab @var{s}  @tab\n\
@item @tab 'end'          @tab @var{e}  @tab\n\
@item @tab 'tokenExtents' @tab @var{te} @tab\n\
@item @tab 'match'        @tab @var{m}  @tab\n\
@item @tab 'tokens'       @tab @var{t}  @tab\n\
@item @tab 'names'        @tab @var{nm}  @tab\n\
@end multitable\n\
\n\
A further optional argument is 'once', that limits the number of returned\n\
matches to the first match. Additional arguments are\n\
\n\
@table @asis\n\
@item matchcase\n\
Make the matching case sensitive.\n\
@item ignorecase\n\
Make the matching case insensitive.\n\
@item stringanchors\n\
Match the anchor characters at the beginning and end of the string.\n\
@item lineanchors\n\
Match the anchor characters at the beginning and end of the line.\n\
@item dotall\n\
The character @code{.} matches the newline character.\n\
@item dotexceptnewline\n\
The character @code{.} matches all but the newline character.\n\
@item freespacing\n\
The pattern can include arbitrary whitespace and comments starting with\n\
@code{#}.\n\
@item literalspacing\n\
The pattern is taken literally.\n\
@end table\n\
@end deftypefn")
{
  octave_value_list retval;
  int nargin = args.length();

  if (nargin < 2)
    print_usage ();
  else if (args(0).is_cell() || args(1).is_cell())
    retval = octcellregexp (args, nargout, "regexp", false);
  else
    retval = octregexp (args, nargout, "regexp", false);

  return retval;
}

/*

## seg-fault test
%!assert(regexp("abcde","."),[1,2,3,4,5])

## Check that anchoring of pattern works correctly
%!assert(regexp('abcabc','^abc'),1);
%!assert(regexp('abcabc','abc$'),4);
%!assert(regexp('abcabc','^abc$'),zeros(1,0));

%!test
%! [s, e, te, m, t] = regexp(' No Match ', 'f(.*)uck');
%! assert (s,zeros(1,0))
%! assert (e,zeros(1,0))
%! assert (te,cell(1,0))
%! assert (m, cell(1,0))
%! assert (t, cell(1,0))

%!test
%! [s, e, te, m, t] = regexp(' FiRetrUck ', 'f(.*)uck');
%! assert (s,zeros(1,0))
%! assert (e,zeros(1,0))
%! assert (te,cell(1,0))
%! assert (m, cell(1,0))
%! assert (t, cell(1,0))

%!test
%! [s, e, te, m, t] = regexp(' firetruck ', 'f(.*)uck');
%! assert (s,2)
%! assert (e,10)
%! assert (te{1},[3,7])
%! assert (m{1}, 'firetruck')
%! assert (t{1}{1}, 'iretr')

%!test
%! [s, e, te, m, t] = regexp('short test string','\w*r\w*');
%! assert (s,[1,12])
%! assert (e,[5,17])
%! assert (size(te), [1,2])
%! assert (isempty(te{1}))
%! assert (isempty(te{2}))
%! assert (m{1},'short')
%! assert (m{2},'string')
%! assert (size(t), [1,2])
%! assert (isempty(t{1}))
%! assert (isempty(t{2}))

%!test
%! [s, e, te, m, t] = regexp('short test string','\w*r\w*','once');
%! assert (s,1)
%! assert (e,5)
%! assert (size(te), [1,1])
%! assert (isempty(te{1}))
%! assert (m{1},'short')
%! ## Matlab gives [1,0] here but that seems wrong.
%! assert (size(t), [1,1])

%!test
%! [m, te, e, s, t] = regexp('short test string','\w*r\w*','once', 'match', 'tokenExtents', 'end', 'start', 'tokens');
%! assert (s,1)
%! assert (e,5)
%! assert (size(te), [1,1])
%! assert (isempty(te{1}))
%! assert (m{1},'short')
%! ## Matlab gives [1,0] here but that seems wrong.
%! assert (size(t), [1,1])

%!testif HAVE_PCRE
%! ## This test is expected to fail if PCRE is not installed
%! [s, e, te, m, t, nm] = regexp('short test string','(?<word1>\w*t)\s*(?<word2>\w*t)');
%! assert (s,1)
%! assert (e,10)
%! assert (size(te), [1,1])
%! assert (te{1}, [1 5; 7, 10])
%! assert (m{1},'short test')
%! assert (size(t),[1,1])
%! assert (t{1}{1},'short')
%! assert (t{1}{2},'test')
%! assert (size(nm), [1,1])
%! assert (!isempty(fieldnames(nm)))
%! assert (sort(fieldnames(nm)),{'word1';'word2'})
%! assert (nm.word1,'short')
%! assert (nm.word2,'test')

%!testif HAVE_PCRE
%! ## This test is expected to fail if PCRE is not installed
%! [nm, m, te, e, s, t] = regexp('short test string','(?<word1>\w*t)\s*(?<word2>\w*t)', 'names', 'match', 'tokenExtents', 'end', 'start', 'tokens');
%! assert (s,1)
%! assert (e,10)
%! assert (size(te), [1,1])
%! assert (te{1}, [1 5; 7, 10])
%! assert (m{1},'short test')
%! assert (size(t),[1,1])
%! assert (t{1}{1},'short')
%! assert (t{1}{2},'test')
%! assert (size(nm), [1,1])
%! assert (!isempty(fieldnames(nm)))
%! assert (sort(fieldnames(nm)),{'word1';'word2'})
%! assert (nm.word1,'short')
%! assert (nm.word2,'test')

%!testif HAVE_PCRE
%! ## This test is expected to fail if PCRE is not installed
%! [t, nm] = regexp("John Davis\nRogers, James",'(?<first>\w+)\s+(?<last>\w+)|(?<last>\w+),\s+(?<first>\w+)','tokens','names');
%! assert (size(t), [1,2]);
%! assert (t{1}{1},'John');
%! assert (t{1}{2},'Davis');
%! assert (t{2}{1},'Rogers');
%! assert (t{2}{2},'James');
%! assert (size(nm), [1,1]);
%! assert (nm.first{1},'John');
%! assert (nm.first{2},'James');
%! assert (nm.last{1},'Davis');
%! assert (nm.last{2},'Rogers');

%!assert(regexp("abc\nabc",'.'),[1:7])
%!assert(regexp("abc\nabc",'.','dotall'),[1:7])
%!testif HAVE_PCRE
%! assert(regexp("abc\nabc",'(?s).'),[1:7])
%! assert(regexp("abc\nabc",'.','dotexceptnewline'),[1,2,3,5,6,7])
%! assert(regexp("abc\nabc",'(?-s).'),[1,2,3,5,6,7])

%!assert(regexp("caseCaSe",'case'),1)
%!assert(regexp("caseCaSe",'case',"matchcase"),1)
%!assert(regexp("caseCaSe",'case',"ignorecase"),[1,5])
%!testif HAVE_PCRE
%! assert(regexp("caseCaSe",'(?-i)case'),1)
%! assert(regexp("caseCaSe",'(?i)case'),[1,5])

%!assert (regexp("abc\nabc",'c$'),7)
%!assert (regexp("abc\nabc",'c$',"stringanchors"),7)
%!testif HAVE_PCRE
%! assert (regexp("abc\nabc",'(?-m)c$'),7)
%! assert (regexp("abc\nabc",'c$',"lineanchors"),[3,7])
%! assert (regexp("abc\nabc",'(?m)c$'),[3,7])

%!assert (regexp("this word",'s w'),4)
%!assert (regexp("this word",'s w','literalspacing'),4)
%!testif HAVE_PCRE
%! assert (regexp("this word",'(?-x)s w','literalspacing'),4)
%! assert (regexp("this word",'s w','freespacing'),zeros(1,0))
%! assert (regexp("this word",'(?x)s w'),zeros(1,0))

%!error regexp('string', 'tri', 'BadArg');
%!error regexp('string');

%!assert(regexp({'asdfg-dfd';'-dfd-dfd-';'qasfdfdaq'},'-'),{6;[1,5,9];zeros(1,0)})
%!assert(regexp({'asdfg-dfd','-dfd-dfd-','qasfdfdaq'},'-'),{6,[1,5,9],zeros(1,0)})
%!assert(regexp({'asdfg-dfd';'-dfd-dfd-';'qasfdfdaq'},{'-';'f';'q'}),{6;[3,7];[1,9]})
%!assert(regexp('Strings',{'t','s'}),{2,7})

*/

DEFUN_DLD (regexpi, args, nargout,
  "-*- texinfo -*-\n\
@deftypefn {Loadable Function} {[@var{s}, @var{e}, @var{te}, @var{m}, @var{t}, @var{nm}] =} regexpi (@var{str}, @var{pat})\n\
@deftypefnx {Loadable Function} {[@dots{}] =} regexpi (@var{str}, @var{pat}, @var{opts}, @dots{})\n\
\n\
Case insensitive regular expression string matching. Matches @var{pat} in\n\
@var{str} and returns the position and matching substrings or empty values\n\
if there are none. See @code{regexp} for more details\n\
@end deftypefn")
{
  octave_value_list retval;
  int nargin = args.length();

  if (nargin < 2)
    print_usage ();
  else if (args(0).is_cell() || args(1).is_cell())
    retval = octcellregexp (args, nargout, "regexpi", true);
  else
    retval = octregexp (args, nargout, "regexpi", true);

  return retval;
}

/*

## seg-fault test
%!assert(regexpi("abcde","."),[1,2,3,4,5])

## Check that anchoring of pattern works correctly
%!assert(regexpi('abcabc','^abc'),1);
%!assert(regexpi('abcabc','abc$'),4);
%!assert(regexpi('abcabc','^abc$'),zeros(1,0));

%!test
%! [s, e, te, m, t] = regexpi(' No Match ', 'f(.*)uck');
%! assert (s,zeros(1,0))
%! assert (e,zeros(1,0))
%! assert (te,cell(1,0))
%! assert (m, cell(1,0))
%! assert (t, cell(1,0))

%!test
%! [s, e, te, m, t] = regexpi(' FiRetrUck ', 'f(.*)uck');
%! assert (s,2)
%! assert (e,10)
%! assert (te{1},[3,7])
%! assert (m{1}, 'FiRetrUck')
%! assert (t{1}{1}, 'iRetr')

%!test
%! [s, e, te, m, t] = regexpi(' firetruck ', 'f(.*)uck');
%! assert (s,2)
%! assert (e,10)
%! assert (te{1},[3,7])
%! assert (m{1}, 'firetruck')
%! assert (t{1}{1}, 'iretr')

%!test
%! [s, e, te, m, t] = regexpi('ShoRt Test String','\w*r\w*');
%! assert (s,[1,12])
%! assert (e,[5,17])
%! assert (size(te), [1,2])
%! assert (isempty(te{1}))
%! assert (isempty(te{2}))
%! assert (m{1},'ShoRt')
%! assert (m{2},'String')
%! assert (size(t), [1,2])
%! assert (isempty(t{1}))
%! assert (isempty(t{2}))

%!test
%! [s, e, te, m, t] = regexpi('ShoRt Test String','\w*r\w*','once');
%! assert (s,1)
%! assert (e,5)
%! assert (size(te), [1,1])
%! assert (isempty(te{1}))
%! assert (m{1},'ShoRt')
%! ## Matlab gives [1,0] here but that seems wrong.
%! assert (size(t), [1,1])

%!test
%! [m, te, e, s, t] = regexpi('ShoRt Test String','\w*r\w*','once', 'match', 'tokenExtents', 'end', 'start', 'tokens');
%! assert (s,1)
%! assert (e,5)
%! assert (size(te), [1,1])
%! assert (isempty(te{1}))
%! assert (m{1},'ShoRt')
%! ## Matlab gives [1,0] here but that seems wrong.
%! assert (size(t), [1,1])

%!testif HAVE_PCRE
%! ## This test is expected to fail if PCRE is not installed
%! [s, e, te, m, t, nm] = regexpi('ShoRt Test String','(?<word1>\w*t)\s*(?<word2>\w*t)');
%! assert (s,1)
%! assert (e,10)
%! assert (size(te), [1,1])
%! assert (te{1}, [1 5; 7, 10])
%! assert (m{1},'ShoRt Test')
%! assert (size(t),[1,1])
%! assert (t{1}{1},'ShoRt')
%! assert (t{1}{2},'Test')
%! assert (size(nm), [1,1])
%! assert (!isempty(fieldnames(nm)))
%! assert (sort(fieldnames(nm)),{'word1';'word2'})
%! assert (nm.word1,'ShoRt')
%! assert (nm.word2,'Test')

%!testif HAVE_PCRE
%! ## This test is expected to fail if PCRE is not installed
%! [nm, m, te, e, s, t] = regexpi('ShoRt Test String','(?<word1>\w*t)\s*(?<word2>\w*t)', 'names', 'match', 'tokenExtents', 'end', 'start', 'tokens');
%! assert (s,1)
%! assert (e,10)
%! assert (size(te), [1,1])
%! assert (te{1}, [1 5; 7, 10])
%! assert (m{1},'ShoRt Test')
%! assert (size(t),[1,1])
%! assert (t{1}{1},'ShoRt')
%! assert (t{1}{2},'Test')
%! assert (size(nm), [1,1])
%! assert (!isempty(fieldnames(nm)))
%! assert (sort(fieldnames(nm)),{'word1';'word2'})
%! assert (nm.word1,'ShoRt')
%! assert (nm.word2,'Test')

%!assert(regexpi("abc\nabc",'.'),[1:7])
%!assert(regexpi("abc\nabc",'.','dotall'),[1:7])
%!testif HAVE_PCRE
%! assert(regexpi("abc\nabc",'(?s).'),[1:7])
%! assert(regexpi("abc\nabc",'.','dotexceptnewline'),[1,2,3,5,6,7])
%! assert(regexpi("abc\nabc",'(?-s).'),[1,2,3,5,6,7])

%!assert(regexpi("caseCaSe",'case'),[1,5])
%!assert(regexpi("caseCaSe",'case',"matchcase"),1)
%!assert(regexpi("caseCaSe",'case',"ignorecase"),[1,5])
%!testif HAVE_PCRE
%! assert(regexpi("caseCaSe",'(?-i)case'),1)
%! assert(regexpi("caseCaSe",'(?i)case'),[1,5])

%!assert (regexpi("abc\nabc",'c$'),7)
%!assert (regexpi("abc\nabc",'c$',"stringanchors"),7)
%!testif HAVE_PCRE
%! assert (regexpi("abc\nabc",'(?-m)c$'),7)
%! assert (regexpi("abc\nabc",'c$',"lineanchors"),[3,7])
%! assert (regexpi("abc\nabc",'(?m)c$'),[3,7])

%!assert (regexpi("this word",'s w'),4)
%!assert (regexpi("this word",'s w','literalspacing'),4)
%!testif HAVE_PCRE
%! assert (regexpi("this word",'(?-x)s w','literalspacing'),4)
%! assert (regexpi("this word",'s w','freespacing'),zeros(1,0))
%! assert (regexpi("this word",'(?x)s w'),zeros(1,0))

%!error regexpi('string', 'tri', 'BadArg');
%!error regexpi('string');

%!assert(regexpi({'asdfg-dfd';'-dfd-dfd-';'qasfdfdaq'},'-'),{6;[1,5,9];zeros(1,0)})
%!assert(regexpi({'asdfg-dfd','-dfd-dfd-','qasfdfdaq'},'-'),{6,[1,5,9],zeros(1,0)})
%!assert(regexpi({'asdfg-dfd';'-dfd-dfd-';'qasfdfdaq'},{'-';'f';'q'}),{6;[3,7];[1,9]})
%!assert(regexpi('Strings',{'t','s'}),{2,[1,7]})

*/


static octave_value
octregexprep (const octave_value_list &args, const std::string &nm)
{
  octave_value retval;
  int nargin = args.length();

  // Make sure we have string,pattern,replacement
  const std::string buffer = args(0).string_value ();
  if (error_state) return retval;
  const std::string pattern = args(1).string_value ();
  if (error_state) return retval;
  const std::string replacement = args(2).string_value ();
  if (error_state) return retval;
  
  // Pack options excluding 'tokenize' and various output
  // reordering strings into regexp arg list
  octave_value_list regexpargs(nargin-1,octave_value());
  regexpargs(0) = args(0);
  regexpargs(1) = args(1);
  int len=2;
  for (int i = 3; i < nargin; i++) 
    {
      const std::string opt = args(i).string_value();
      if (opt != "tokenize" && opt != "start" && opt != "end"
	  && opt != "tokenextents" && opt != "match" && opt != "tokens"
	  && opt != "names"  && opt != "warnings") 
	{
	  regexpargs(len++) = args(i);
	}
    }
  regexpargs.resize(len);
  
  // Identify replacement tokens; build a vector of group numbers in
  // the replacement string so that we can quickly calculate the size 
  // of the replacement.
  int tokens = 0;
  for (size_t i=1; i < replacement.size(); i++) 
    {
      if (replacement[i-1]=='$' && isdigit(replacement[i])) 
	{
	  tokens++, i++;
	}
    }
  std::vector<int> token(tokens);
  int kk = 0;
  for (size_t i = 1; i < replacement.size(); i++) 
    {
      if (replacement[i-1]=='$' && isdigit(replacement[i])) 
	{
	  token[kk++] = replacement[i]-'0';
	  i++;
	}
    }

  // Perform replacement
  std::string rep;
  if (tokens > 0) 
    {
      std::list<regexp_elem> lst;
      string_vector named;
      int nopts;
      int sz = octregexp_list (regexpargs, nm , false, lst, named, nopts);

      if (error_state)
	return retval;
      if (sz == 0)
	{
	  retval = args(0);
	  return retval;
	}

      // Determine replacement length
      const size_t replen = replacement.size() - 2*tokens;
      int delta = 0;
      const_iterator p = lst.begin();
      for (int i = 0; i < sz; i++) 
	{
	  OCTAVE_QUIT;

	  const Matrix pairs(p->te);
	  size_t pairlen = 0;
	  for (int j = 0; j < tokens; j++) 
	    {
	      if (token[j] == 0) 
		pairlen += static_cast<size_t>(p->e - p->s) + 1;
	      else if (token[j] <= pairs.rows()) 
		pairlen += static_cast<size_t>(pairs(token[j]-1,1) - 
					       pairs(token[j]-1,0)) + 1;
	    }
	  delta += static_cast<int>(replen + pairlen) - 
	    static_cast<int>(p->e - p->s + 1);
	  p++;
	}
      
      // Build replacement string
      rep.reserve(buffer.size()+delta);
      size_t from = 0;
      p = lst.begin();
      for (int i=0; i < sz; i++) 
	{
	  OCTAVE_QUIT;

	  const Matrix pairs(p->te);
	  rep.append(&buffer[from], static_cast<size_t>(p->s - 1) - from);
	  from = static_cast<size_t>(p->e - 1) + 1;
	  for (size_t j = 1; j < replacement.size(); j++) 
	    {
	      if (replacement[j-1]=='$' && isdigit(replacement[j])) 
		{
		  int k = replacement[j]-'0';
		  if (k == 0) 
		    { 
		      // replace with entire match
		      rep.append(&buffer[static_cast<size_t>(p->e - 1)],
				 static_cast<size_t>(p->e - p->s) + 1);
		    } 
		  else if (k <= pairs.rows()) 
		    {
		      // replace with group capture
		      rep.append(&buffer[static_cast<size_t>(pairs(k-1,0)-1)],
				 static_cast<size_t>(pairs(k-1,1) - 
						     pairs(k-1,0))+1);
		    }
		  else 
		    {
		      // replace with nothing
		    }
		  j++;
		} 
	      else 
		{
		  rep.append(1,replacement[j-1]);
		}
	      if (j+1 == replacement.size()) 
		{
		  rep.append(1,replacement[j]);
		}
	    }
	  p++;
	}
      rep.append(&buffer[from],buffer.size()-from);
    } 
  else 
    {
      std::list<regexp_elem> lst;
      string_vector named;
      int nopts;
      int sz = octregexp_list (regexpargs, nm, false, lst, named,nopts);

      if (error_state)
	return retval;
      if (sz == 0)
	{
	  retval = args(0);
	  return retval;
	}

      // Determine replacement length
      const size_t replen = replacement.size();
      int delta = 0;
      const_iterator p = lst.begin();
      for (int i = 0; i < sz; i++) 
	{
          OCTAVE_QUIT;
	  delta += static_cast<int>(replen) - 
	    static_cast<int>(p->e - p->s + 1);
	  p++;
	}

      // Build replacement string
      rep.reserve(buffer.size()+delta);
      size_t from = 0;
      p = lst.begin();
      for (int i=0; i < sz; i++) 
	{
          OCTAVE_QUIT;
	  rep.append(&buffer[from], static_cast<size_t>(p->s - 1) - from);
	  from = static_cast<size_t>(p->e - 1) + 1;
	  rep.append(replacement);
	  p++;
	}
      rep.append(&buffer[from],buffer.size()-from);
    }
  
  retval = rep;
  return retval;
}

DEFUN_DLD (regexprep, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Loadable Function}  {@var{string} =} regexprep (@var{string}, @var{pat}, @var{repstr}, @var{options})\n\
Replace matches of @var{pat} in  @var{string} with @var{repstr}.\n\
\n\
\n\
The replacement can contain @code{$i}, which substitutes\n\
for the ith set of parentheses in the match string.  E.g.,\n\
@example\n\
\n\
   regexprep(\"Bill Dunn\",'(\\w+) (\\w+)','$2, $1')\n\
\n\
@end example\n\
returns \"Dunn, Bill\"\n\
\n\
@var{options} may be zero or more of\n\
@table @samp\n\
\n\
@item once\n\
Replace only the first occurrence of @var{pat} in the result.\n\
\n\
@item warnings\n\
This option is present for compatibility but is ignored.\n\
\n\
@item ignorecase or matchcase\n\
Ignore case for the pattern matching (see @code{regexpi}).\n\
Alternatively, use (?i) or (?-i) in the pattern.\n\
\n\
@item lineanchors and stringanchors\n\
Whether characters ^ and $ match the beginning and ending of lines.\n\
Alternatively, use (?m) or (?-m) in the pattern.\n\
\n\
@item dotexceptnewline and dotall\n\
Whether . matches newlines in the string.\n\
Alternatively, use (?s) or (?-s) in the pattern.\n\
\n\
@item freespacing or literalspacing\n\
Whether whitespace and # comments can be used to make the regular expression more readable.\n\
Alternatively, use (?x) or (?-x) in the pattern.\n\
\n\
@end table\n\
@seealso{regexp,regexpi}\n\
@end deftypefn")
{
  octave_value_list retval;
  int nargin = args.length();

  if (nargin < 3)
    {
      print_usage ();
      return retval;
    }

  if (args(0).is_cell() || args(1).is_cell() || args(2).is_cell())
    {
      Cell str;
      Cell pat;
      Cell rep;
      dim_vector dv0;
      dim_vector dv1(1,1);

      if (args(0).is_cell())
	str = args(0).cell_value();
      else
	str = Cell (args(0));

      if (args(1).is_cell())
	pat = args(1).cell_value();
      else
	pat = Cell (args(1));

      if (args(2).is_cell())
	rep = args(2).cell_value();
      else
	rep = Cell (args(2));

      dv0 = str.dims();
      if (pat.numel() != 1)
	{
	  dv1 = pat.dims();
	  if (rep.numel() != 1 && dv1 != rep.dims())
	    error ("regexprep: Inconsistent cell array dimensions");
	}
      else if (rep.numel() != 1)
	dv1 = rep.dims();

      if (!error_state)
	{
	  Cell ret (dv0);
	  octave_value_list new_args = args;

	  for (octave_idx_type i = 0; i < dv0.numel(); i++)
	    {
	      new_args(0) = str(i);
	      if (pat.numel() == 1)
		new_args(1) = pat(0);
	      if (rep.numel() == 1)
		new_args(2) = rep(0);
	      for (octave_idx_type j = 0; j < dv1.numel(); j++)
		{
		  if (pat.numel() != 1)
		    new_args(1) = pat(j);
		  if (rep.numel() != 1)
		    new_args(2) = rep(j);
		  new_args(0) = octregexprep (new_args, "regexprep");

		  if (error_state)
		    break;
		}

	      if (error_state)
		break;

	      ret(i) = new_args(0);
	    }

	  if (!error_state)
	    retval = octave_value (ret);
	}
    }
  else
    retval = octregexprep (args, "regexprep");

  return retval;
}

/*
%!test  # Replace with empty
%! xml = '<!-- This is some XML --> <tag v="hello">some stuff<!-- sample tag--></tag>';
%! t = regexprep(xml,'<[!?][^>]*>','');
%! assert(t,' <tag v="hello">some stuff</tag>')

%!test  # Replace with non-empty
%! xml = '<!-- This is some XML --> <tag v="hello">some stuff<!-- sample tag--></tag>';
%! t = regexprep(xml,'<[!?][^>]*>','?');
%! assert(t,'? <tag v="hello">some stuff?</tag>')

%!test  # Check that 'tokenize' is ignored
%! xml = '<!-- This is some XML --> <tag v="hello">some stuff<!-- sample tag--></tag>';
%! t = regexprep(xml,'<[!?][^>]*>','','tokenize');
%! assert(t,' <tag v="hello">some stuff</tag>')

%!testif HAVE_PCRE # Capture replacement
%! data = "Bob Smith\nDavid Hollerith\nSam Jenkins";
%! result = "Smith, Bob\nHollerith, David\nJenkins, Sam";
%! t = regexprep(data,'(?m)^(\w+)\s+(\w+)$','$2, $1');
%! assert(t,result)

# Return the original if no match
%!assert(regexprep('hello','world','earth'),'hello')

## Test a general replacement
%!assert(regexprep("a[b]c{d}e-f=g", "[^A-Za-z0-9_]", "_"), "a_b_c_d_e_f_g");

## Make sure it works at the beginning and end
%!assert(regexprep("a[b]c{d}e-f=g", "a", "_"), "_[b]c{d}e-f=g");
%!assert(regexprep("a[b]c{d}e-f=g", "g", "_"), "a[b]c{d}e-f=_");

## Options
%!assert(regexprep("a[b]c{d}e-f=g", "[^A-Za-z0-9_]", "_", "once"), "a_b]c{d}e-f=g");
%!assert(regexprep("a[b]c{d}e-f=g", "[^A-Z0-9_]", "_", "ignorecase"), "a_b_c_d_e_f_g");

## Option combinations
%!assert(regexprep("a[b]c{d}e-f=g", "[^A-Z0-9_]", "_", "once", "ignorecase"), "a_b]c{d}e-f=g");

## End conditions on replacement
%!assert(regexprep("abc","(b)",".$1"),"a.bc");
%!assert(regexprep("abc","(b)","$1"),"abc");
%!assert(regexprep("abc","(b)","$1."),"ab.c");
%!assert(regexprep("abc","(b)","$1.."),"ab..c");

## Test cell array arguments
%!assert(regexprep("abc",{"b","a"},"?"),{"??c"})
%!assert(regexprep({"abc","cba"},"b","?"),{"a?c","c?a"})
%!assert(regexprep({"abc","cba"},{"b","a"},{"?","!"}),{"!?c","c?!"})

*/

/*
;;; Local Variables: ***
;;; mode: C++ ***
;;; End: ***
*/