----- Original Message -----
Sent: Monday, June 02, 2003 5:47 AM
Subject: one more little thing about
upvalues
In lua book (BTW, a question to Roberto: how high
is the finishing of THE BOOK in your priority list? ;-) there is an
interesting example of using upvalues in Lua4:
sin = function (x)
return %sin(x*180/PI)
end
This thing is not directly reproducible in Lua5,
right? The way to do this in 5.0 I can think of is
this:
local old_sin = sin
sin = function (x)
return old_sin(x*math.pi/180) -- updated
to Lua5 specifics: convert back to accepting degrees ;-)
end
Is this right? Is this the only way? Will it work
just the same? (I tested it to some expent, it produced similar result on my
test script for Lua4 and Lua5 versions).
P.S. I wonder if this discussion of upvalues os
of use to anybody (even me): those who use closure know what it is, those who
don't know - well, then just do not use them
8-)
