mex_pattern.cpp

#include "mex.h"

/*
 * Doing this works and is easy enough to maintain but it is kind of annoying.
 * There are code generators and argument parsers out there, 
 * but they can complicate the code even more.
 * Named optional parameters and other complexities should just be handled by a matlab wrapper. 
 */

// I meant this string was useless but it also describes this file
#define MEX_ERR_ID "pointless:boilerplate"



bool assert_type(bool correct_type, int index, char *name, char *should_be){
	if (!correct_type){
		// index + 1 because matlab starts at 1
		mexErrMsgIdAndTxt(MEX_ERR_ID, "Argument %d (%s) should be %s.", index + 1, name, should_be);
	}
}

void mexFunction(int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[]){
    
	int arg_count = -1;
	
	const int foo_index = ++arg_count;
	const int bar_index = ++arg_count;
	const int optional_index = ++arg_count;
	
	int required_arguments = bar_index + 1;
	
	if (nrhs < required_arguments || nrhs > arg_count){
		usage_error();
	}
	
	const mxArray *foo_arg = prhs[foo_index];
	const mxArray *bar_arg = prhs[bar_index];
	const mxArray *optional_arg = optional_index < nrhs ? prhs[optional_index] : NULL;
	
	assert_type(mxIsDouble(foo_arg), foo_index, "foo", "a double array");
	assert_type(is_scalar_double(bar_arg), bar_index, "bar", "a number");
	
	if (optional_arg) assert_type(mxIsDouble(optional_arg), optional_index, "optional", "a double array");
	
	const double *foo = mxGetPr(foo_arg);
	int bar = (int) mxGetScalar(bar)
	... optional ...
	plhs ... out
	do_thing_better_than_matlab(foo, bar, optional, out);
	
}