Hi. I'm trying to parse an simple string expression to something
like Element array. Each Element can have a value of unknown
type, which will be further combined and calculated to let say
real/double/float value, no mather.
In Java i had something like generics and this could be
implemented like:
class Element<T> {
T value;
Element(T value){
this.value=value;
}
}
class Parser{
Collection<Element<?>> parse(String expression){
Collection<Element<?>> retVal = new ArrayList<>();
//"expression" would be parser but for this example lets say
we just create new elements
Element<Integer> e1= new Element<>();
e1.value=3;
Element<String> e2 = new Element<>();
e2.value="+"
retValue.add(e1);
retValue.add(e2);
...
return retValue;
}
}
And then in other class not connected through module or template
parameter or anything i could call it just:
Parser p = new Parser();
Collection<Element<?>> elements=p.parse("(1+2+3)/6");
and then check weather (element.value instanceof Operator) or
other stuff.
if i do something like this in D:
module calculator;
class Element(T) {
T value;
this(T value){
this.value=value;
}
}
and then:
Element[] parse(string expression){
Element[] returnSlice;
...
//"expression" would be parser but for this example
lets say we just create new elements
Element!(int) e1 = new Element();
e1.value=3;
Element!(string) e2= new Element();
e2.value="+";
returnSlice~=e1;
returnSlice~=e2;
return returnSlice;
}
I'm getting error:
class calculator.Element used as a type.
How to represent this class template parameter T of Element(T) as
wildcard Element(?) ??
Cheers Voitech
