Hello! I'm struggling with some of the Factor's words. Mostly with `when-empty`, `if-zero` and similar. It's difficult for me to understand why they don't work sometimes, while their simpler counterparts (while, if) do work exactly as expected.
Here's the latest installment of my struggle: IN: scratchpad USE: crypto.xor [ [ empty-xor-key ] when-empty ] infer. ( x -- x ) Why is the stack effect as shown here? The documentation for `when-empty` says it takes `( seq quot -- )`. Therefore, I expect `[ [ empty-xor-key ] when-empty ] infer.` to output `( x -- )`. When I modify the quotation passed to `when-empty` to be a no-op, I get a compilation error: IN: scratchpad [ [ 1 drop ] when-empty ] infer. Error The input quotations to “if-empty” don't match their expected effects Input Expected Got [ 1 drop ] ( ..a -- ..b ) ( -- ) [ ] ( ..a seq -- ..b ) ( -- ) That's completely weird to me. Is the stack effect in the documentation incorrect? Should it be `( seq quot -- seq )`? And why does it refuse to compile the second example with `1 drop`? ---=====--- Александр ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, SlashDot.org! http://sdm.link/slashdot _______________________________________________ Factor-talk mailing list Factor-talk@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/factor-talk
