I think that's because the above semantics correspond more directly to assembly language, which I imagine was done because "switch" was defined back when that was either important or just not seen to be bad. (Perhaps I'm just making that up, though.) Here's how a switch statement would look in x64 assembly:
switch:
;put desired thing in rax, let's say
case_1:
cmp rax, val_1
jne case_2 ;jump if not equal
<case 1 code>
case_2:
cmp rax, val_2
jne case_3
<case 2 code>
case_3:
cmp rax, val_2
jne done
<case 3 code>
done:
<whatever>
By default, the machine will just plow through the remaining cases. If you want it to break out after one case, you have to tell it to do so:
switch:
;put desired thing in rax, let's say
case_1:
cmp rax, val_1
jne case_2 ;jump if not equal
<case 1 code>
jmp done ;jump.
case_2:
cmp rax, val_2
jne case_3
<case 2 code>
jmp done
case_3:
cmp rax, val_2
jne done
<case 3 code>
done:
<whatever>
Assembly language is kind of awesome, by the way. And so is the Miller-Rabin primality test. Some disorganized code: http://pastebin.com/raw.php?i=wRyQ2NAx
Fine. That's great and all for C, but I dislike how Java copied C word-for-word, and then JavaScript copied Java. It would have been nice if they had said, "hm... using continue rather than break would make a lot more sense."
It's not a huge deal, and developers can simply avoid switch if they don't like it. My point was merely that "JavaScript's switch sucks, Arc's (case) is awesome."
