Description of slinvoke

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slinvoke

PURPOSE

SLINVOKE Invokes a function

SYNOPSIS

function varargout = slinvoke(invoke_descr, varargin)

DESCRIPTION

SLINVOKE Invokes a function

 $ Syntax $
   - [y1, y2, ..., yn] = slinvoke(invoke_descr, x1, x2, ..., xm)

 $ Arguments $
   - invoke_descr:       the invoking descriptor
   - x1, x2, ..., xm:    the input arguments
   - y1, y2, ..., yn:    the output arguments

 $ Description $
   - [y1, y2, ..., yn] = slinvoke(invoke_descr, placepos, x1, x2, ..., xm) 
     invokes some function with a specified manner. The invoking descriptor
     can be in following form:
     1. a string representing the function name, a function handle or an 
        inline object. In this case, no fixed argument is binded. The x1, 
        x2, ..., xm are directly fed to the function.
     2. a cell array like {func, var_pos, fa1, fa2, ... fak}. Here
        func is the function name, function handle or inline object that
        is to be invoked. var_pos is the positions of variable arguments.
        fa1, fa2, ... are the fixed(binded) arguments. If var_pos is [],
        the variable arguments will be put first.

 $ Examples $
   - Invoke a function without fixed arguments
     \{
           slinvoke('plot', x, y);
           y = slinvoke({'sin', []}, x);
     \}

   - Invoke a function with fixed arguments binded, the following pairs
     of statements are equivalent.
     \{
           K = slinvoke({'strfind', 1, 'pattern'}, s);
           K = strfind(s, 'pattern');

           slinvoke({'plot', [1 2], 'r-'}, x, y);
           plot(x, y, 'r-');

           slinvoke({'plot', 2, x, 'b+'}, y);
           plot(x, y, 'b+');

           b = slinvoke({'isequal', [], 0}, x);
           b = isequal(x, 0);
     \}

 $ History $
   - Created by Dahua Lin on Dec 28th, 2005

CROSS-REFERENCE INFORMATION

This function calls:

This function is called by:

SOURCE CODE

0001 function varargout = slinvoke(invoke_descr, varargin)
0002 %SLINVOKE Invokes a function
0003 %
0004 % $ Syntax $
0005 %   - [y1, y2, ..., yn] = slinvoke(invoke_descr, x1, x2, ..., xm)
0006 %
0007 % $ Arguments $
0008 %   - invoke_descr:       the invoking descriptor
0009 %   - x1, x2, ..., xm:    the input arguments
0010 %   - y1, y2, ..., yn:    the output arguments
0011 %
0012 % $ Description $
0013 %   - [y1, y2, ..., yn] = slinvoke(invoke_descr, placepos, x1, x2, ..., xm)
0014 %     invokes some function with a specified manner. The invoking descriptor
0015 %     can be in following form:
0016 %     1. a string representing the function name, a function handle or an
0017 %        inline object. In this case, no fixed argument is binded. The x1,
0018 %        x2, ..., xm are directly fed to the function.
0019 %     2. a cell array like {func, var_pos, fa1, fa2, ... fak}. Here
0020 %        func is the function name, function handle or inline object that
0021 %        is to be invoked. var_pos is the positions of variable arguments.
0022 %        fa1, fa2, ... are the fixed(binded) arguments. If var_pos is [],
0023 %        the variable arguments will be put first.
0024 %
0025 % $ Examples $
0026 %   - Invoke a function without fixed arguments
0027 %     \{
0028 %           slinvoke('plot', x, y);
0029 %           y = slinvoke({'sin', []}, x);
0030 %     \}
0031 %
0032 %   - Invoke a function with fixed arguments binded, the following pairs
0033 %     of statements are equivalent.
0034 %     \{
0035 %           K = slinvoke({'strfind', 1, 'pattern'}, s);
0036 %           K = strfind(s, 'pattern');
0037 %
0038 %           slinvoke({'plot', [1 2], 'r-'}, x, y);
0039 %           plot(x, y, 'r-');
0040 %
0041 %           slinvoke({'plot', 2, x, 'b+'}, y);
0042 %           plot(x, y, 'b+');
0043 %
0044 %           b = slinvoke({'isequal', [], 0}, x);
0045 %           b = isequal(x, 0);
0046 %     \}
0047 %
0048 % $ History $
0049 %   - Created by Dahua Lin on Dec 28th, 2005
0050 %
0051 
0052 
0053 %% parse input arguments
0054 if ~iscell(invoke_descr)
0055     func = invoke_descr;
0056     var_pos =[];
0057     fix_args = {};
0058 else
0059     len_invoke_descr = length(invoke_descr);
0060     func = invoke_descr{1};
0061     if len_invoke_descr >= 2
0062         var_pos = invoke_descr{2};
0063     else
0064         var_pos = [];
0065     end
0066     if len_invoke_descr >= 3
0067         fix_args = invoke_descr(3:end);
0068     else
0069         fix_args = {};
0070     end
0071 end
0072 
0073 if isempty(var_pos) && ~isempty(varargin)
0074     var_pos = 1:length(varargin);
0075 end
0076 n_fix_args = length(fix_args);
0077 n_var_args = length(var_pos);
0078 if length(varargin) ~= n_var_args
0079     error('sltoolbox:argmismatch', ...
0080         'The variable input arguments do not match that described in invoking descriptor');
0081 end
0082 
0083 
0084 %% organize input arguments
0085 if n_fix_args == 0 && n_var_args == 0
0086     if nargout == 0
0087         feval(func);
0088     else
0089         [varargout{1:nargout}] = feval(func);
0090     end
0091 elseif n_var_args == 0
0092     if nargout == 0
0093         feval(func, fix_args{:});
0094     else
0095         [varargout{1:nargout}] = feval(func, fix_args{:});
0096     end
0097 else
0098     n_args = max(n_fix_args + n_var_args, max(var_pos));
0099     input_args = cell(1, n_args);
0100     indicator_var = false(1, n_args);
0101     indicator_var(var_pos) = true; 
0102     fix_pos = find(~indicator_var);
0103     
0104     for i = 1 : n_var_args
0105         input_args{var_pos(i)} = varargin{i};
0106     end
0107     
0108     for i = 1 : n_fix_args
0109         input_args{fix_pos(i)} = fix_args{i};
0110     end
0111     
0112     if nargout == 0
0113         feval(func, input_args{:});
0114     else
0115         [varargout{1:nargout}] = feval(func, input_args{:});
0116     end
0117 end
0118 
0119 
0120     
0121 
0122 
0123

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