## Copyright (C) 2011-2018 Carnë Draug
##
## 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
## <https://www.gnu.org/licenses/>.

## -*- texinfo -*-
## @deftypefn {} {@var{p} =} inputParser ()
## Create object @var{p} of the inputParser class.
##
## This class is designed to allow easy parsing of function arguments.  The
## class supports four types of arguments:
##
## @enumerate
## @item mandatory (see @command{addRequired});
##
## @item optional (see @command{addOptional});
##
## @item named (see @command{addParameter});
##
## @item switch (see @command{addSwitch}).
## @end enumerate
##
## After defining the function API with these methods, the supplied arguments
## can be parsed with the @command{parse} method and the parsing results
## accessed with the @command{Results} accessor.
##
## @end deftypefn
## @deftypefn {} {} inputParser.Parameters
## Return list of parameter names already defined.
##
## @end deftypefn
## @deftypefn {} {} inputParser.Results
## Return structure with argument names as fieldnames and corresponding values.
##
## @end deftypefn
## @deftypefn {} {} inputParser.Unmatched
## Return structure similar to @command{Results}, but for unmatched parameters.
## See the @command{KeepUnmatched} property.
##
## @end deftypefn
## @deftypefn {} {} inputParser.UsingDefaults
## Return cell array with the names of arguments that are using default values.
##
## @end deftypefn
## @deftypefn {} {} inputParser.CaseSensitive = @var{boolean}
## Set whether matching of argument names should be case sensitive.  Defaults
## to false.
##
## @end deftypefn
## @deftypefn {} {} inputParser.FunctionName = @var{name}
## Set function name to be used in error messages; Defaults to empty string.
##
## @end deftypefn
## @deftypefn {} {} inputParser.KeepUnmatched = @var{boolean}
## Set whether an error should be given for non-defined arguments.  Defaults to
## false.  If set to true, the extra arguments can be accessed through
## @code{Unmatched} after the @code{parse} method.  Note that since
## @command{Switch} and @command{Parameter} arguments can be mixed, it is
## not possible to know the unmatched type.  If argument is found unmatched
## it is assumed to be of the @command{Parameter} type and it is expected to
## be followed by a value.
##
## @end deftypefn
## @deftypefn {} {} inputParser.StructExpand = @var{boolean}
## Set whether a structure can be passed to the function instead of
## parameter/value pairs.  Defaults to true.
##
## The following example shows how to use this class:
##
## @example
## function check (varargin)
## @c The next two comments need to be indented by one for alignment
##   p = inputParser ();                      # create object
##   p.FunctionName = "check";                # set function name
##   p.addRequired ("pack", @@ischar);         # mandatory argument
##   p.addOptional ("path", pwd(), @@ischar);  # optional argument
##
##   ## create a function handle to anonymous functions for validators
##   val_mat = @@(x) isvector (x) && all (x <= 1) && all (x >= 0);
##   p.addOptional ("mat", [0 0], val_mat);
##
##   ## create two arguments of type "Parameter"
##   val_type = @@(x) any (strcmp (x, @{"linear", "quadratic"@}));
##   p.addParameter ("type", "linear", val_type);
##   val_verb = @@(x) any (strcmp (x, @{"low", "medium", "high"@}));
##   p.addParameter ("tolerance", "low", val_verb);
##
##   ## create a switch type of argument
##   p.addSwitch ("verbose");
##
##   p.parse (varargin@{:@});  # Run created parser on inputs
##
##   ## the rest of the function can access inputs by using p.Results.
##   ## for example, get the tolerance input with p.Results.tolerance
## endfunction
## @end example
##
## @example
## @group
## check ("mech");           # valid, use defaults for other arguments
## check ();                 # error, one argument is mandatory
## check (1);                # error, since ! ischar
## check ("mech", "~/dev");  # valid, use defaults for other arguments
##
## check ("mech", "~/dev", [0 1 0 0], "type", "linear");  # valid
##
## ## following is also valid.  Note how the Switch argument type can
## ## be mixed into or before the Parameter argument type (but it
## ## must still appear after any Optional argument).
## check ("mech", "~/dev", [0 1 0 0], "verbose", "tolerance", "high");
##
## ## following returns an error since not all optional arguments,
## ## `path' and `mat', were given before the named argument `type'.
## check ("mech", "~/dev", "type", "linear");
## @end group
## @end example
##
## @emph{Note 1}: A function can have any mixture of the four API types but
## they must appear in a specific order.  @command{Required} arguments must be
## first and can be followed by any @command{Optional} arguments.  Only
## the @command{Parameter} and @command{Switch} arguments may be mixed
## together and they must appear at the end.
##
## @emph{Note 2}: If both @command{Optional} and @command{Parameter} arguments
## are mixed in a function API then once a string Optional argument fails to
## validate it will be considered the end of the @command{Optional}
## arguments.  The remaining arguments will be compared against any
## @command{Parameter} or @command{Switch} arguments.
##
## @seealso{nargin, validateattributes, validatestring, varargin}
## @end deftypefn

## -*- texinfo -*-
## @deftypefn  {} {} addOptional (@var{argname}, @var{default})
## @deftypefnx {} {} addOptional (@var{argname}, @var{default}, @var{validator})
## Add new optional argument to the object @var{parser} of the class
## inputParser to implement an ordered arguments type of API
##
## @var{argname} must be a string with the name of the new argument.  The order
## in which new arguments are added with @command{addOptional}, represents the
## expected order of arguments.
##
## @var{default} will be the value used when the argument is not specified.
##
## @var{validator} is an optional anonymous function to validate the given
## values for the argument with name @var{argname}.  Alternatively, a
## function name can be used.
##
## See @command{help inputParser} for examples.
##
## @emph{Note}: if a string argument does not validate, it will be considered a
## ParamValue key.  If an optional argument is not given a validator, anything
## will be valid, and so any string will be considered will be the value of the
## optional argument (in @sc{matlab}, if no validator is given and argument is
## a string it will also be considered a ParamValue key).
##
## @end deftypefn

## -*- texinfo -*-
## @deftypefn  {} {} addParameter (@var{argname}, @var{default})
## @deftypefnx {} {} addParameter (@var{argname}, @var{default}, @var{validator})
## Add new parameter to the object @var{parser} of the class inputParser to
## implement a name/value pair type of API.
##
## @var{argname} must be a string with the name of the new parameter.
##
## @var{default} will be the value used when the parameter is not specified.
##
## @var{validator} is an optional function handle to validate the given values
## for the parameter with name @var{argname}.  Alternatively, a function name
## can be used.
##
## See @command{help inputParser} for examples.
##
## @end deftypefn

## -*- texinfo -*-
## @deftypefn  {} {} addParamValue (@var{argname}, @var{default})
## @deftypefnx {} {} addParamValue (@var{argname}, @var{default}, @var{validator})
## Add new parameter to the object @var{parser} of the class inputParser to
## implement a name/value pair type of API.
##
## This is an alias for @command{addParameter} method without the
## @qcode{"PartialMatchPriority"} option.  See it for the help text.
##
## @end deftypefn

## -*- texinfo -*-
## @deftypefn  {} {} addRequired (@var{argname})
## @deftypefnx {} {} addRequired (@var{argname}, @var{validator})
## Add new mandatory argument to the object @var{parser} of inputParser class.
##
## This method belongs to the inputParser class and implements an ordered
## arguments type of API.
##
## @var{argname} must be a string with the name of the new argument.  The order
## in which new arguments are added with @command{addrequired}, represents the
## expected order of arguments.
##
## @var{validator} is an optional function handle to validate the given values
## for the argument with name @var{argname}.  Alternatively, a function name
## can be used.
##
## See @command{help inputParser} for examples.
##
## @emph{Note}: this can be used together with the other type of arguments but
## it must be the first (see @command{@@inputParser}).
##
## @end deftypefn

## -*- texinfo -*-
## @deftypefn {} {} addSwitch (@var{argname})
## Add new switch type of argument to the object @var{parser} of inputParser
## class.
##
## This method belongs to the inputParser class and implements a switch
## arguments type of API.
##
## @var{argname} must be a string with the name of the new argument.  Arguments
## of this type can be specified at the end, after @code{Required} and
## @code{Optional}, and mixed between the @code{Parameter}.  They default to
## false.  If one of the arguments supplied is a string like @var{argname},
## then after parsing the value of @var{parse}.Results.@var{argname} will be
## true.
##
## See @command{help inputParser} for examples.
##
## @end deftypefn

## -*- texinfo -*-
## @deftypefn {} {} parse (@var{varargin})
## Parses and validates list of arguments according to object @var{parser} of
## the class inputParser.
##
## After parsing, the results can be accessed with the @command{Results}
## accessor.  See @command{help inputParser} for a more complete description.
##
## @end deftypefn

## Author: Carnë Draug <carandraug@octave.org>

classdef inputParser < handle
  properties
    ## FIXME: set input checking for these properties
    CaseSensitive = false;
    FunctionName  = "";
    KeepUnmatched = false;
    PartialMatching = false; # FIXME: unimplemented (and default should be true)
    StructExpand    = true;
  endproperties

  properties (SetAccess = protected)
    Parameters    = cell ();
    Results       = struct ();
    Unmatched     = struct ();
    UsingDefaults = cell ();
  endproperties

  properties (Access = protected)
    ## Since Required and Optional are ordered, they get a cell array of
    ## structs with the fields "name", "def" (default), and "val" (validator).
    Required = cell ();
    Optional = cell ();
    ## Parameter and Switch are unordered so we have a struct whose fieldnames
    ## are the argname, and values are a struct with fields "def" and "val"
    Parameter = struct ();
    Switch    = struct ();

    ## List of Parameter and Switch names to ease searches
    ParameterNames = cell ();
    SwitchNames    = cell ();

    ## When checking for fieldnames in a Case Insensitive way, this variable
    ## holds the correct identifier for the last searched named using the
    ## is_argname method.
    last_name = "";
  endproperties

  properties (Access = protected, Constant = true)
    ## Default validator, always returns scalar true.
    def_val = @() true;
  endproperties

  methods
    function set.PartialMatching (this, val)
      if (val)
        error ("inputParser: PartialMatching is not yet implemented");
      endif
    endfunction

    function addRequired (this, name, val = inputParser.def_val)
      if (nargin < 2 || nargin > 3)
        print_usage ();
      elseif (numel (this.Optional) || numfields (this.Parameter)
              || numfields (this.Switch))
        error (["inputParser.addRequired: can't have a Required argument " ...
                "after Optional, Parameter, or Switch"]);
      endif
      this.validate_name ("Required", name);
      this.Required{end+1} = struct ("name", name, "val", val);
    endfunction

    function addOptional (this, name, def, val = inputParser.def_val)
      if (nargin < 3 || nargin > 4)
        print_usage ();
      elseif (numfields (this.Parameter) || numfields (this.Switch))
        error (["inputParser.Optional: can't have Optional arguments " ...
                "after Parameter or Switch"]);
      endif
      this.validate_name ("Optional", name);
      this.Optional{end+1} = struct ("name", name, "def", def, "val", val);
    endfunction

    function addParamValue (this, name, def, val = inputParser.def_val)
      if (nargin < 3 || nargin > 4)
        print_usage ();
      endif
      this.addParameter (name, def, val);
    endfunction

    function addParameter (this, name, def, varargin)
      if (nargin < 3 || nargin > 6)
        print_usage ();
      endif

      n_opt = numel (varargin);

      if (n_opt == 0 || n_opt == 2)
        val = inputParser.def_val;
      else # n_opt is 1 or 3
        val = varargin{1};
      endif

      if (n_opt == 0 || n_opt == 1)
        match_priority = 1;
      else # n_opt is 2 or 3
        if (! strcmpi (varargin{end-1}, "PartialMatchPriority"))
          error ("inputParser.addParameter: unrecognized option");
        endif
        match_priority = varargin{end};
        validateattributes (match_priority, {"numeric"}, {"positive", "integer"},
                            "inputParser.addParameter",
                            "PartialMatchPriority");
      endif

      this.validate_name ("Parameter", name);
      this.Parameter.(name).def = def;
      this.Parameter.(name).val = val;
    endfunction

    function addSwitch (this, name)
      if (nargin != 2)
        print_usage ();
      endif
      this.validate_name ("Switch", name);
      this.Switch.(name).def = false;
    endfunction

    function parse (this, varargin)
      this.Results = struct ();
      this.Unmatched = struct ();
      this.UsingDefaults = cell ();
      if (numel (varargin) < numel (this.Required))
        if (this.FunctionName)
          print_usage (this.FunctionName);
        else
          this.error ("inputParser.parse: not enough input arguments");
        endif
      endif
      pnargin = numel (varargin);

      this.ParameterNames = fieldnames (this.Parameter);
      this.SwitchNames    = fieldnames (this.Switch);

      ## Evaluate the Required arguments first
      nReq = numel (this.Required);
      for idx = 1:nReq
        req = this.Required{idx};
        this.validate_arg (req.name, req.val, varargin{idx});
      endfor

      vidx = nReq;  # current index in varargin

      ## Search for a list of Optional arguments
      idx  = 0;     # current index on the array of Optional
      nOpt = numel (this.Optional);
      while (vidx < pnargin && idx < nOpt)
        opt = this.Optional{++idx};
        in  = varargin{++vidx};
        if ((this.is_argname ("Parameter", in) && vidx < pnargin)
            || this.is_argname ("Switch", in))
          ## This looks like an optional parameter/value pair or a
          ## switch, not an positional option.  This does mean that
          ## positional options cannot be strings named like parameter
          ## keys.  See bug #50752.
          idx -= 1;
          vidx -= 1;
          break
        endif
        try
          valid_option = opt.val (in);
        catch
          valid_option = false;
        end_try_catch
        if (! valid_option)
          ## If it does not match there's two options:
          ##    1) input is actually wrong and we should error;
          ##    2) it's a Parameter or Switch name and we should use
          ##       the default for the rest;
          ##    3) it's a struct with the Parameter pairs.
          if (ischar (in) || (this.StructExpand && isstruct (in)
                              && isscalar (in)))
            idx -= 1;
            vidx -= 1;
            break
          else
            this.error (sprintf (["failed validation of %s\n", ...
                                  "Validation function: %s"],
                                 toupper (opt.name), disp(opt.val)));
          endif
        endif
        this.Results.(opt.name) = in;
      endwhile

      ## Fill in with defaults of missing Optional
      while (idx++ < nOpt)
        opt = this.Optional{idx};
        this.UsingDefaults{end+1} = opt.name;
        this.Results.(opt.name) = opt.def;
      endwhile

      ## Search unordered Options (Switch and Parameter)
      while (vidx++ < pnargin)
        name = varargin{vidx};

        if (this.StructExpand && isstruct (name) && isscalar (name))
          expanded_options = [fieldnames(name) struct2cell(name)]'(:);
          n_new_args = numel (expanded_options) -1;
          pnargin += n_new_args;
          varargin(vidx+n_new_args+1:pnargin) = varargin(vidx+1:end);
          varargin(vidx:vidx+n_new_args) = expanded_options;
          name = varargin{vidx};
        endif

        if (! ischar (name))
          this.error ("non-string for Parameter name or Switch");
        endif

        if (this.is_argname ("Parameter", name))
          if (vidx++ > pnargin)
            this.error (sprintf ("no matching value for option '%s'",
                                 toupper (name)));
          endif
          this.validate_arg (this.last_name,
                             this.Parameter.(this.last_name).val,
                             varargin{vidx});
        elseif (this.is_argname ("Switch", name))
          this.Results.(this.last_name) = true;
        else
          if (vidx++ < pnargin && this.KeepUnmatched)
            this.Unmatched.(name) = varargin{vidx};
          else
            this.error (sprintf ("argument '%s' is not a valid parameter",
                                 toupper (name)));
          endif
        endif
      endwhile
      ## Add them to the UsingDefaults list
      this.add_missing ("Parameter");
      this.add_missing ("Switch");

    endfunction

    function disp (this)
      if (nargin != 1)
        print_usage ();
      endif
      printf ("inputParser object with properties:\n\n");
      b2s = @(x) ifelse (any (x), "true", "false");
      printf (["   CaseSensitive   : %s\n   FunctionName    : %s\n" ...
               "   KeepUnmatched   : %s\n   PartialMatching : %s\n" ...
               "   StructExpand    : %s\n\n"],
               b2s (this.CaseSensitive), b2s (this.FunctionName),
               b2s (this.KeepUnmatched), b2s (this.PartialMatching),
               b2s (this.StructExpand));
      printf ("Defined parameters:\n\n   {%s}\n",
              strjoin (this.Parameters, ", "));
    endfunction
  endmethods

  methods (Access = private)
    function validate_name (this, type, name)
      if (! isvarname (name))
        error ("inputParser.add%s: NAME is an invalid identifier", method);
      elseif (any (strcmpi (this.Parameters, name)))
        ## Even if CaseSensitive is "on", we still shouldn't allow
        ## two args with the same name.
        error ("inputParser.add%s: argname '%s' has already been specified",
               type, name);
      endif
      this.Parameters{end+1} = name;
    endfunction

    function validate_arg (this, name, val, in)
        if (! val (in))
          this.error (sprintf ("failed validation of %s with %s",
                               toupper (name), func2str (val)));
        endif
        this.Results.(name) = in;
    endfunction

    function r = is_argname (this, type, name)
      if (this.CaseSensitive)
        r = isfield (this.(type), name);
        this.last_name = name;
      else
        fnames = this.([type "Names"]);
        l = strcmpi (name, fnames);
        r = any (l(:));
        if (r)
          this.last_name = fnames{l};
        endif
      endif
    endfunction

    function add_missing (this, type)
      unmatched = setdiff (fieldnames (this.(type)), fieldnames (this.Results));
      for namec = unmatched(:)'
        name = namec{1};
        this.UsingDefaults{end+1} = name;
        this.Results.(name) = this.(type).(name).def;
      endfor
    endfunction

    function error (this, msg)
      where = "";
      if (this.FunctionName)
        where = [this.FunctionName ": "];
      endif
      error ("%s%s", where, msg);
    endfunction
  endmethods

endclassdef

%!function p = create_p ()
%!  p = inputParser ();
%!  p.CaseSensitive = true;
%!  p.addRequired ("req1", @(x) ischar (x));
%!  p.addOptional ("op1", "val", @(x) any (strcmp (x, {"val", "foo"})));
%!  p.addOptional ("op2", 78, @(x) x > 50);
%!  p.addSwitch ("verbose");
%!  p.addParameter ("line", "tree", @(x) any (strcmp (x, {"tree", "circle"})));
%!endfunction

## check normal use, only required are given
%!test
%! p = create_p ();
%! p.parse ("file");
%! r = p.Results;
%! assert (r.req1, "file");
%! assert (sort (p.UsingDefaults), sort ({"op1", "op2", "verbose", "line"}));
%! assert ({r.req1, r.op1, r.op2, r.verbose, r.line},
%!         {"file", "val", 78,    false,     "tree"});

## check normal use, but give values different than defaults
%!test
%! p = create_p ();
%! p.parse ("file", "foo", 80, "line", "circle", "verbose");
%! r = p.Results;
%! assert ({r.req1, r.op1, r.op2, r.verbose, r.line},
%!         {"file", "foo", 80,    true,      "circle"});

## check optional is skipped and considered Parameter if unvalidated string
%!test
%! p = create_p ();
%! p.parse ("file", "line", "circle");
%! r = p.Results;
%! assert ({r.req1, r.op1, r.op2, r.verbose, r.line},
%!         {"file", "val", 78,    false,     "circle"});

## check case insensitivity
%!test
%! p = create_p ();
%!  p.CaseSensitive = false;
%! p.parse ("file", "foo", 80, "LiNE", "circle", "vERbOSe");
%! r = p.Results;
%! assert ({r.req1, r.op1, r.op2, r.verbose, r.line},
%!         {"file", "foo", 80,    true,      "circle"});

## check KeepUnmatched
%!test
%! p = create_p ();
%! p.KeepUnmatched = true;
%! p.parse ("file", "foo", 80, "line", "circle", "verbose", "extra", 50);
%! assert (p.Unmatched.extra, 50);

## check error when missing required
%!error <not enough input arguments>
%! p = create_p ();
%! p.parse ();

## check error when given required does not validate
%!error <failed validation of >
%! p = create_p ();
%! p.parse (50);

## check error when given optional does not validate
%!error <is not a valid parameter>
%! p = create_p ();
%! p.parse ("file", "no-val");

## check error when given Parameter does not validate
%!error <failed validation of >
%! p = create_p ();
%! p.parse ("file", "foo", 51, "line", "round");

## check alternative method (obj, ...) API
%!function p2 = create_p2 ();
%!  p2 = inputParser;
%!  addRequired (p2, "req1", @(x) ischar (x));
%!  addOptional (p2, "op1", "val", @(x) any (strcmp (x, {"val", "foo"})));
%!  addOptional (p2, "op2", 78, @(x) x > 50);
%!  addSwitch (p2, "verbose");
%!  addParameter (p2, "line", "tree", @(x) any (strcmp (x, {"tree", "circle"})));
%!endfunction

## check normal use, only required are given
%!test
%! p2 = create_p2 ();
%! parse (p2, "file");
%! r = p2.Results;
%! assert ({r.req1, r.op1, r.op2, r.verbose, r.line},
%!         {"file", "val", 78,    false,     "tree"});
%! assert (sort (p2.UsingDefaults), sort ({"op1", "op2", "verbose", "line"}));

## check normal use, but give values different than defaults
%!test
%! p2 = create_p2 ();
%! parse (p2, "file", "foo", 80, "line", "circle", "verbose");
%! r = p2.Results;
%! assert ({r.req1, r.op1, r.op2, r.verbose, r.line},
%!         {"file", "foo", 80,    true,      "circle"});

## We must not perform validation of default values
%!test <*45837>
%! p = inputParser;
%! p.addParameter ("Dir", [], @ischar);
%! p.parse ();
%! assert (p.Results.Dir, []);

%!test
%! p = inputParser;
%! p.addParameter ("positive", -1, @(x) x > 5);
%! p.parse ();
%! assert (p.Results.positive, -1);

## Throw an error on validation of optional argument to check that it
## is caught without preventing continuation into param/value pairs.
%!test
%! p = inputParser ();
%! p.addOptional ("err", "foo", @error);
%! p.addParameter ("not_err", "bar", @ischar);
%! p.parse ("not_err", "qux");
%! assert (p.Results.err, "foo")
%! assert (p.Results.not_err, "qux")


## With more Parameters to test StructExpand
%!function p3 = create_p3 ();
%!  p3 = inputParser;
%!  addOptional (p3, "op1", "val", @(x) any (strcmp (x, {"val", "foo"})));
%!  addOptional (p3, "op2", 78, @(x) x > 50);
%!  addSwitch (p3, "verbose");
%!  addParameter (p3, "line", "tree", @(x) any (strcmp (x, {"tree", "circle"})));
%!  addParameter (p3, "color", "red", @(x) any (strcmp (x, {"red", "green"})));
%!  addParameter (p3, "style", "tt", @(x) any (strcmp (x, {"tt", "f", "i"})));
%!endfunction

## Test StructExpand
%!test
%! p3 = create_p3 ();
%! p3.parse (struct ("line", "circle", "color", "green"));
%! assert (p3.Results, struct ("op1", "val", "op2", 78, "verbose", false,
%!                             "line", "circle", "color", "green",
%!                             "style", "tt"))

%!test
%! p3 = create_p3 ();
%! p3.parse (struct ("line", "circle", "color", "green"), "line", "tree");
%! assert (p3.Results.line, "tree")
%! p3.parse ("line", "tree", struct ("line", "circle", "color", "green"));
%! assert (p3.Results.line, "circle")

%!test # unmatched parameters with StructExpand
%! p3 = create_p3 ();
%! p3.KeepUnmatched = true;
%! p3.parse (struct ("line", "circle", "color", "green", "bar", "baz"));
%! assert (p3.Unmatched.bar, "baz")

## The validation for the second optional argument throws an error with
## a struct so check that we can handle it.
%!test
%! p3 = create_p3 ();
%! p3.parse ("foo", struct ("color", "green"), "line", "tree");
%! assert (p3.Results.op1, "foo")
%! assert (p3.Results.line, "tree")
%! assert (p3.Results.color, "green")
%! assert (p3.Results.verbose, false)


## Some simple tests for addParamValue since all the other ones use add
## addParameter but they use the same codepath.
%!test
%! p = inputParser;
%! addParameter (p, "line", "tree", @(x) any (strcmp (x, {"tree", "circle"})));
%! addParameter (p, "color", "red", @(x) any (strcmp (x, {"red", "green"})));
%! p.parse ("line", "circle");
%! assert ({p.Results.line, p.Results.color}, {"circle", "red"})

%!test
%! p = inputParser;
%! p.addParameter ("foo", "bar", @ischar);
%! p.parse ();
%! assert (p.Results, struct ("foo", "bar"))
%! p.parse ("foo", "qux");
%! assert (p.Results, struct ("foo", "qux"))

## This behaviour means that a positional option can never be a string
## that is the name of a parameter key.  This is required for Matlab
## compatibility.
%!test <*50752>
%! p = inputParser ();
%! p.addOptional ("op1", "val");
%! p.addParameter ("line", "tree");
%! p.parse ("line", "circle");
%! assert (p.Results, struct ("op1", "val", "line", "circle"))
%!
%! p = inputParser ();
%! p.addOptional ("op1", "val1");
%! p.addOptional ("op2", "val2");
%! p.addParameter ("line", "tree");
%! p.parse ("line", "circle");
%! assert (p.Results.op1, "val1")
%! assert (p.Results.op2, "val2")
%! assert (p.Results.line, "circle")
%!
%! ## If there's enough arguments to fill the positional options and
%! ## param/key, it still skips positional options.
%! p = inputParser ();
%! p.addOptional ("op1", "val1");
%! p.addOptional ("op2", "val2");
%! p.addParameter ("line", "tree");
%! p.parse ("line", "circle", "line", "rectangle");
%! assert (p.Results, struct ("op1", "val1", "op2", "val2",
%!                            "line", "rectangle"))
%!
%! ## Even if the key/param fails validation, it does not backtrack to
%! ## check if the values are valid positional options.
%! p = inputParser ();
%! p.addOptional ("op1", "val1", @ischar);
%! p.addOptional ("op2", "val2", @isnumeric);
%! p.addParameter ("line", "circle", @ischar);
%! fail ('p.parse ("line", 89)', "failed validation of LINE")
%!
%! p = inputParser ();
%! p.addOptional ("op1", "val1");
%! p.addParamValue ("line", "circle", @ischar);
%! fail ('p.parse ("line", "line", 89)',
%!       "non-string for Parameter name or Switch")

%!test <*50752>
%! ## This fails in Matlab but works in Octave.  It is a bug there
%! ## that we do not replicate.
%! p = inputParser ();
%! p.addOptional ("op1", "val1");
%! p.addParameter ("line", "circle");
%! p.parse ("line");
%! assert (p.Results, struct ("op1", "line", "line", "circle"))

%!test <*50752>
%! p = inputParser;
%! p.addOptional ("op1", "val1");
%! p.addSwitch ("line");
%! p.parse ("line");
%! assert (p.Results.op1, "val1")
%! assert (p.Results.line, true)

%!test
%! p = inputParser;
%! p.addParameter ("a", []);
%! p.addParameter ("b", []);
%! p.parse ("a", 1);
%! p.parse ("b", 1);
%! assert (p.Results, struct ("a", [], "b", 1));
%! assert (p.UsingDefaults, {"a"});

%!test
%! p = inputParser;
%! p.addParameter ("b", []);
%! p.KeepUnmatched = true;
%! p.parse ("a", 1);
%! p.parse ("b", 1);
%! assert (p.Results, struct ("b", 1));
%! assert (p.Unmatched, struct ());

## Test for patch #9241
%!error<failed validation of A with ischar>
%! p = inputParser;
%! p.addParameter ("a", [], @ischar);
%! p.parse ("a", 1);
