Re: __plt__.m redundancies

[Rik]

On 06/27/2013 10:31 AM, Daniel J Sebald wrote:
> On 06/27/2013 11:44 AM, Rik wrote:
>> 6/27/13
>>
>> All,
>>
>> I happened to be looking in scripts/plot/private/__plt__.m and found that
>> there is a dispatch table in the subfunction __plt2__ which checks whether
>> the x input is a scalar, vector, or matrix and whether the y input is a
>> scalar, vector, or matrix and then calls the appropriate subfunction such
>> as __plt2sv__ for scalar/vector plotting.
>>
>> I checked in each of the 6 subfunctions and they check the number of input
>> arguments with nargin as well as re-checking that each of the inputs is a
>> scalar, vector, or matrix.  This is redundant and probably arose as the
>> code evolved in time.  Does anyone know why the input checks in the leaf
>> functions cannot be deleted in favor of the earlier checks?
>>
>> --Rik
>
> I'm not seeing this redundancy.  What line numbers or code hunks?
The dispatch table is in the __plt2__ subfunction at line 231.  Here it is
just to give the flavor:

  if (isempty (x1) && isempty (x2))
    retval = zeros (0, 1);
  elseif (isscalar (x1))
    if (isscalar (x2))
      retval = __plt2ss__ (h, x1, x2, options, properties);
    elseif (isvector (x2))
      retval = __plt2sv__ (h, x1, x2, options, properties);
    else
      error ("__plt2__: invalid data for plotting");
    endif
  elseif (isvector (x1))
    if (isscalar (x2))
      retval = __plt2vs__ (h, x1, x2, options, properties);
    elseif (isvector (x2))
      retval = __plt2vv__ (h, x1, x2, options, properties);
    elseif (ismatrix (x2))
      retval = __plt2vm__ (h, x1, x2, options, properties);
    else
      error ("__plt2__: invalid data for plotting");
    endif
  elseif (ismatrix (x1))
    if (isvector (x2))
      retval = __plt2mv__ (h, x1, x2, options, properties);
    elseif (ismatrix (x2))
      retval = __plt2mm__ (h, x1, x2, options, properties);
    else
      error ("__plt2__: invalid data for plotting");
    endif
  else
    error ("__plt2__: invalid data for plotting");
  endif

Each of the subfunctions is __plt2[svm][svm]__ where s is scalar, v is
vector, and m is matrix.  As an example, here is the start of __plt2ss__
which is for plotting scalar/scalar such as plot (1,1).

function retval = __plt2ss__ (h, x, y, options, properties)

  if (nargin < 3 || nargin > 5)
    print_usage ();
  endif

  if (nargin < 4 || isempty (options))
    options = __default_plot_options__ ();
  endif

  if (nargin < 5)
    properties = {};
  endif

  if (numel (options) > 1)
    options = options(1);
  endif

  if (isscalar (x) && isscalar (y))
    linestyle = options.linestyle;
    marker = options.marker;
    if (isempty (marker) && isempty (linestyle))
      ## If unspecified, marker for a single point is always "."
      linestyle = "-";
      marker = ".";
    endif
    color = options.color;
    if (isempty (color))
      color = __next_line_color__ ();
    endif

    retval = line (x, y, "color", color,
                   "linestyle", linestyle,
                   "marker", marker, properties{:});
  else
    error ("__plt2ss__: arguments must be scalars");
  endif

As you can see, there is quite a bit of option validating and this seems
unnecessary.

--Rik