Random_seed behaves differently when called as a function or as a subroutine. I am not sure if this is the expected behaviour. I am running yorick 2.2.02x. The following demonstrates this difference (starting in a fresh yorick):

I would have guessed that calling random_seed as a function would return the current random seed.

Hello,

The problem is that Y_random_seed drops all its arguments and left nothing on top of the stack so when you call it as a function (without storing the result in a variable) the interpreter "displays" the result (the topmost stack item) which is the function itself and thus re-execute random_seed without any argument this time which reset the seed to a default value as you correctly guessed.

The fix is easy: just discard: at the last line of function Y_random_seed in std1.c (line number 1120). Then the result of calling random_seed will be its argument (whatever it is). Another possibility could be to push a boolean (scalar int) to indicate whether the call was successful or not.

I am not allowed to push changes into Yorick repository so I left Dave decides if it is worth fixing this bug...

Commit 58b3486 "fixes" this. It is still an error to invoke random_seed as a function, but now its return value is its input instead of the function itself.

Just to make it clear what's going on, here's an interpreted function that acts like random_seed used to: