> With that I was able to debug the problem in a snap. It turns out that one
> of my functions had "readlines(open(...))" instead of
> "open(readlines,...)". The critical difference is that the former leaves a
> file pointer dangling.
>
Ah, ok, that's exactly the difference: using open(myfunc, filename) is the
same as
open(filename) do io
myfunc(io)
end
Like this you never have to worry about closing files, even on exceptions.
When using open without a function it looks like this:
io = open(filename)
myfunc(io)
# this is crucial:
close(io)
In this version, when an exception occurs in myfunc the file will never be
closed.
Last note: the "do" syntax is not special for open but can be used with
your own functions as well:
function functhatneedsfunc(f, a)
println("let's just apply f")
f(a)
end
# lets call it:
functhatneedsfunc(a) do x
show(x)
println("printed x!")
end
