On 25-Jan-07, at 5:21 PM, Jan Schütze wrote:
Correct.
But only for error and exception handling.
I don't need it to handle an failure or an exception, its normal case
- so there should be a normal function to do this, without such a big
(and good working!) workaround, which Romulo posted.
Surely if you call a function "die", you're implying that it's a
response to a failure or exceptional condition :) In which case, using
an error() based exception system seems entirely appropriate.
If you want to do a "compressed return" from a nested recursion, you
should think seriously about coroutines, which make that convenient,
as well as being more flexible because they give the option of
accepting a result or continuing a search.
For example:
trythis = coroutine.yield
function find()
for value in some_query(database) do
find2(database, value)
end
end
function find2(database, value)
for value2 in some_other_query(database, value) do
find3(database, value, value2)
end
end
function find3(database, v1, v2)
for result in yet_another_query(database, v1, v2) do
trythis(result)
end
end
-- main search
local function search()
local finder = coroutine.wrap(find)
local result
repeat
result = finder()
if checks_out(result) then return result end
until not result
end
error "Not found"
end
Just posted mainly to help improving lua with what is often needed in
developing web. applications. But you are correct, depends on the
point of view, and where(/how often) you need such functionality.
