assert()
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- Subject: assert()
- From: "Peter Hill" <corwin@...>
- Date: Sun, 2 Feb 2003 23:21:17 +0800
I've been reading through the "How to Program in Lua Draft" (mentioned on
the list a few days ago) and I noticed the suggested use of "assert()" as a
guard against unexpected errors in functions that return 'nil' to signal an
error has occured. So:
assert(readline("test"))
Or even:
x = assert( f() )
But what if the function normally returns multiple values? According to the
Lua5(beta) manual "assert" is equivalent to:
function assert (v, m)
if not v then
error(m or "assertion failed!")
end
return v
end
so:
a,b,c = assert( f() )
would be doomed to failure (as 'b' and 'c' would never be assigned) :-(.
Would it not make more sense to define "assert()" as:
function assert(v, ...)
if not v then
error(arg[1] or "assertion failed!")
end
return v, unpack(arg)
end
*cheers*
Peter Hill.