syntactic-sugar

I'm learning Zend Framework at the moment and came across the following syntax. class Zend_Controller_Action_Helper_Redirector extends Zend_Controller_Action_Helper_Abstract { /** * Perform a redirect to an action/controller/module with params * * @param string $action * @param string $controller * @param string $module * @param array $params * @return void */ public function gotoSimple($action, $controller = null, $module = null, array $params = array()) { $this->setGotoSimple($action, $controller, $module, $params); if ($this->getExit()) { $this->redirectAndExit(); } } /** * direct():

In Prolog, [H|T] is the list that begins with H and where the remaining elements are in the list T (internally represented with '.'(H, '.'(…)) ). Is it possible to define new syntax in a similar fashion? For example, is it possible to define that [T~H] is the list that ends with H and where the remaining elements are in the list T , and then use it as freely as [H|T] in heads and bodies of predicates? Is it also possible to define e.g. <H|T> to be a different structure than lists? One can interpret your question literally. A list-like data structure, where accessing the tail can be expressed

I have been trying to implement apply function in Rcpp so far the code looks like this //[[Rcpp::export]] NumericVector apply(NumericMatrix x,int dim,Function f){ NumericVector output; if(dim==1){ for(int i=0;i<x.nrow();i++){ output[i]=f(x(i,_)); } } else if(dim==2){ for(int i=0;i<x.ncol();i++){ output[i]=f(x(_,i)); } } return(output); } but i'm getting an error "cannot convert SEXP to double in assignment" in line 6 and 11. Is there any way to convert the value returned by an arbitrary function to double? also is there a sugar function for the apply function. There is no sugar function for

Would it make sense to have a " constify " operation in C/C++ that makes a variable const ? Here is an example where it could be useful, where obviously we don't want to declare it const yet in the first line: std::vector<int> v; v.push_back(5); constify v; // now it's const Currently, without such a possibility, you'd have to introduce another variable to get the same effect: std::vector<int> v0; v0.push_back(5); const std::vector<int>& v = v0; That's more confusing since it adds a new name into the scope and you need to make it a reference to avoid copying the whole vector (or use swap ?).