What is the difference between \startlua and \startluacode?

Question

Is there any difference between \startlua and \startluacode? The commands seem to have a similar purpose, but I have found some code does compile properly if the wrong one is chosen. When is one used? When is the other?

Answer 1

The difference are the catcodes. \startlua uses TeX catcodes, startluacode uses Lua catcodes. Two examples:

\starttext

\startlua
-- fails both
-- context("Foo %Bar")
-- %context("Foo \n Bar")
\stoplua

\startluacode
-- prints Foo
-- context("Foo %Bar")

-- prints Foo Bar
context("Foo \n Bar")
\stopluacode

\stoptext

For more information you can have a look at the source file luat-ini.mkiv.