The new syntax is <local *toclose x = f()>. The mark '*' allows other
attributes to be added later without the need of new keywords; it
also allows better error messages. The API function was also renamed
('lua_tobeclosed' -> 'lua_toclose').
Statements like 'if cond then goto label' generate code so that the
jump in the 'if' goes directly to the given label. This optimization
cannot be done when the jump is backwards leaving the scope of some
variable, as it cannot add the needed 'close' instruction. (The jumps
were already generated by the 'if'.)
This commit also added 'likely'/'unlikely' for tests for errors in
the parser, and it changed the way breaks outside loops are detected.
(Now they are detected like other goto's with undefined labels.)
Added restriction that, when a label is created, there cannot be
another label with the same name visible. That allows backward goto's
to be resolved when they are read. Backward goto's get a close if
they jump out of the scope of some variable; labels get a close only
if previous goto to it jumps out of the scope of some upvalue.
From the point of view of 'git', all names are relative to the root
directory of the project. So, file names in '$Id:' also should be
relative to that directory: the proper name for test file 'all.lua'
is 'testes/all.lua'.
Roberto Ierusalimschy