Factor/FAQ/Unanswered questions

Add ideas for questions here, and we'll answer them and incorporate the answers into the FAQ.

Q: How are hashes implemented in Factor? Generically, how can hashes be implemented efficiently within a language where the principle data structure is a stack?

I've added an answer to Develop.

Q: how do I inspect the source code of a word?

• - metaperl

Q: If I were going to create a series of vocabularies based around text, is there hierarchy support? e.g. text.lorem, text.leetspeak, text.balanced

or should they have just underscores in their name? textlorem

A: there's hierarchy support. USE: foo.bar loads foo/bar/bar.factor

Q: Say I have '5' on the stack, and I want to create a sequence { 1 x 3 } and place 5 where the x is, what's the best way to do this?

slava: 5 1 swap 3 3array

slava: or 5 :> x { 1 x 3 }

slava: prunedtree would suggest something like 5 1array { 1 } { 3 } surround [ ] map

Q: I keep USE:ing source files from the listener but when I play with them in the listener, they do not have the search paths that the source file loaded!

A:

the only way to change the listener's search path is by entering USING:, USE:, etc in the listener

the first time, USE: will load the vocabulary, but any USE: or USING: in the source file that gets loaded will not affect the listener

slava: methods don't belong to a vocabulary

slava: methods belong to a generic word

slava: to invoke a generic word, you have to have the generic word's vocabulary in your search path

metaperl: I think that might trip up a lot of people

slava: well, its how java import statements owrk

slava: it only affects the source file being parsed

slava: I guess python and ruby just stick everything in one global namespace

slava: so you load a source file which loads another source file and suddently you've got 30 new identifiers in the global scope, some of which clash with your existing ones :)

Q: I keep killing the listener and restarting to make sure all my definitions get refreshed. Is there a simpler way?

A: if you just want to reload the source file, do refresh-all in the listener

you don't have to restart it