switch will not match case single item statements in some cases.

dworkin / dgd

Dworkin's Game Driver, an object-oriented database management system originally used to run MUDs.

https://www.dworkin.nl/dgd/

GNU Affero General Public License v3.0

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switch will not match case single item statements in some cases. #87

Closed knubo closed 8 months ago

knubo commented 8 months ago

The following code does not match 0 in the switch.

int bink() {
  int size, i;
  object ob;
  string sizestr;

  sizestr = "Change me";

  size = 0;
  switch (size) {
  case 0:
    sizestr = "tiny ";
    break;
  case 1: sizestr = "little "; break;
  case 2: sizestr = "small "; break;
  case 3..5: sizestr = ""; break;
  case 6: sizestr = "large "; break;
  case 7: sizestr = "big "; break;
  case 8: sizestr = "huge "; break;
  }

  write("Huh:"+sizestr+"\n");
  return size;
}

Whereas a much simpler case do work:


void working_switch() {
  int s,i;
  string x;

  s = 0;

  switch(s) {
  case 0:
    x = "0 case";
    break;
  case 1:
    write("Huh\n");
    break;
  }

  write(x);
}

Found on Viking.

geirpg commented 8 months ago

Further investigation of the bug:

It only appears when you mix singular values and ranges.
Ranges such as 1..1 still bugs
It only affects the first case. Other cases work as expected.
It doesn't matter if the first case is a range or singular case, the first case still bugs, the other cases still work.
If the first case is a range, it will only bug for the first value of that range. remaining values in the range works.
However, if the first case is a singular value, and the remaining cases are ranges, it works as expected, but as soon as you introduce singular values into the mix, it bugs.

switch(size) { case 0: sizestr = "tiny";break; case 1..2: sizestr = "little";break; case 3: sizestr ="small ";break; }

this will fail for case 0. If case 3 is instead 3..4, everything will work just fine.

//geirpg / Moreldir@vikingmud