06:59 <perspectivet> hi, I'm new to the channel and new to ocaml, though once a regular use of sml

07:01 <perspectivet> What is the idiomatic way to read a structured multi-type binary file?

07:05 <perspectivet> I've found the extLib IO class to be pretty helpful so far, but reading the binary stream into a hand constructed class seems pretty weak.

07:07 <perspectivet> record initialization oddness doesn't seem to lend itself to an elegant solution either.

08:29 <flux__> hmm.. I'm thinking one elegant way would be, for type foo = { a: string; b: int}; to provide something like let foo_structure = [`A, `String (255, encode_string); `B, `Int (4, encode_int)] and then the loading function would look something like let write_foo foo = let buf = Buffer.create () in let s = encode buf foo

08:29 <flux__> oh, that was writing, I wonder if it's more difficult for reading ;)

08:30 <flux__> encode should also refer to foo_structure

08:30 <flux__> sigh, I fixed my code into something that cannot work

08:31 <flux__> let write_foo foo = let buf = Buffer.create () in let s = encode buf foo_structure; s `A foo.a; s `B foo.b was what I was thinking

08:31 <flux__> the reading part is going to be more complex, though

08:33 <perspectivet> I've been reading through the camlp4 tutorial. a syntax extension seem to be the way to go. though it's still not simple.

08:33 <flux__> let read_foo () = let s = decode buffer_in foo_structure in let a = destring (s `A) in let b = destring (s `B) in { a: a; b: b}

08:33 <flux__> yes, syntax extension would give you much cleaner code, and may be wortwhile if you're doing lots of that

08:34 <flux__> (actually s/destring/identity/; s/destring/int_of_string/)

08:34 <perspectivet> Yah, I'll probably be doing a lot of it.

08:39 <perspectivet> flux__: thanx for the help, btw. Make me think a little deeper on the problem than I have.

08:39 <perspectivet> Still thinking C++-ish about the problem. Not good.

08:41 <flux__> good luck with your project

08:43 <perspectivet> thanks.