Adding Comefrom to LuaJIT

tedunangst.com

63 points·mr_tyzic··8 comments

I recognize that this is just for fun, but can't help linking this anyway:

http://www.freelists.org/post/luajit/Turning-Lua-into-C-was-...

I'm disappointed that he didn't implement the infinitely more useful "PLEASE COMEFROM (LABEL) STEP (INTEGER)"

Would using a macro system such as http://metalua.luaforge.net/metalua-manual.html be another way of doing this ?

This blog post reminded me of Lua's rather non-conformist older cousin Tcl. Shaping your own control structure is an idiomatic thing to do in Tcl thanks (or perhaps, but no thanks) to uplevel and upvar. I wish there was a standard goto (no pun intended) place exclusively reserved for creative hacks using those two. There probably is such a page on Tclers wiki, if not it very well deserves to be there.

I don't think metalua is compatible with LuaJIT. Or has this changed?

You are correct it emits Lua bytecode and not LuaJIT bytecode. Wasn't there a refactoring of metalua in progress to facilitate porting ? It would be tedious work but there should not be any fundamental blockers.

> A return statement is only valid at the end of a block, which means if the control flow introduces new blocks, they may not behave as such without if true return end wrapping.

do return end

Is there a "Cotton Eye Joe" reference here?

Nope, it's from INTERCAL[1], which is (obviously) an abbreviation for Compiler Language With No Pronounceable Acronym.

[1] https://en.wikipedia.org/wiki/INTERCAL

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