default case matches multiple times for same term in a visit

[mahills]

If I do the following in an otherwise empty module:

import Traversal;
import IO;

void doit() {
    l = [1,"one",2,"two",3,"three"];
    bottom-up visit(l) {
        case int n : println("<n> is an int");
        default: {
            println("Found the default");
        }
    }
}

and run it I see the following:

rascal>doit();
1 is an int
Found the default
Found the default
Found the default
2 is an int
Found the default
Found the default
Found the default
3 is an int
Found the default
Found the default
Found the default
Found the default
Found the default
Found the default
ok

Why is default being triggered so many times? I would think it would be triggered at most 4 times, one for each of the 3 strings in the list, and one for the list as a whole.

[josvanroosmalen]

Because it will also visit for string chars.

Do tot see what is going PN:

default value x: { println("no visitor for <x>")

[josvanroosmalen]

Sorry should be:

case value x:  { println("No visitor for <x>"); }

This will give:

rascal>doit();
1 is an int
Found the default one
Found the default ne
Found the default e
2 is an int
Found the default two
Found the default wo
Found the default o
3 is an int
Found the default three
Found the default hree
Found the default ree  
Found the default ee
Found the default e
Found the default [1,"one",2,"two",3,"three"]
ok

[mahills]

Question: is this really the behavior we want? This seems amazingly expensive, and not terribly consistent (matching each character inside the string would make more sense if we were going to do this, I would think).

[PaulKlint]

As usual, I have executed this example with the compiler, and I think that gives the behavior we want:

import Traversal;
import IO;

void doit() {
    l = [1,"one",2,"two",3,"three"];
    bottom-up visit(l) {
        case int n : println("<n> is an int");
        case value x:  { println("No case for <x>"); }
    }
}

and get:

1 is an int
No case for one
2 is an int
No case for two
3 is an int
No case for three
No case for [1,"one",2,"two",3,"three"]

In the compiler, only top-level string visits match every character.

[mahills]

I think that makes much more sense, this is what I would expect.

[jurgenvinju]

We should make a separate statement kind for top-level string visits, like edit(s) { case ... }. The current overloading of visit is hard to spot and inconsistent with the case oF visiting a string that is nested.