## -*- mode: octave; -*-

function txt = unimplemented (fcn)

  is_matlab_function = true;

  ## Some smarter cases, add more as needed.
  switch (fcn)

  case "importdata"
    txt = ["importdata is not implemented.  Similar functionality is ",...
    "available through @code{load}, @code{dlmread}, @code{csvread}, ",...
    "or @code{textscan}."];  

  case "quad2d"
    txt = ["quad2d is not implemented.  Consider using dblquad."];

  case "gsvd"
    txt = ["gsvd is not currently part of core Octave.  See the ",...
    "linear-algebra package at ",...
    "@url{http://octave.sourceforge.net/linear-algebra/}."];

  case "linprog"
    txt = ["Octave does not currently provide linprog.  ",...
    "Linear programming problems may be solved using @code{glpk}.  ",...
    "Try @code{help glpk} for more info."];

  case {"ode113", "ode15i", "ode15s", "ode23", "ode23s", "ode23t", "ode45", "odeget", "odeset"}
    txt = ["Octave provides lsode for solving differential equations.  ",...
    "For more information try @code{help lsode}.  ",...
    "Matlab-compatible ODE functions are provided by the odepkg package.  ",...
    "See @url{http://octave.sourceforge.net/odepkg/}."];

  otherwise
    if (ismember (fcn, missing_functions ()))
      txt = sprintf ("the '%s' function is not yet implemented in Octave", fcn);
    else
      is_matlab_function = false;
      txt = "";
    endif
  endswitch

  if (is_matlab_function)
    txt = [txt, "\n\n@noindent\nPlease read ",...
           "@url{http://www.octave.org/missing.html} to learn how ",...
           "you can contribute missing functionality."];
    txt = __makeinfo__ (txt);
  endif

  if (nargout == 0)
    warning ("Octave:missing-function", "%s", txt);
  endif

endfunction