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What is a match statement translated into?
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Date: 2007-08-18 (07:42)
From: Jacques GARRIGUE <garrigue@m...>
Subject: Re: [Caml-list] What is a match statement translated into?
From: Joel Reymont <joelr1@gmail.com>

> Is pattern-matching code in OCaml expanded into threaded code (pre- 
> computed branch table) or something analogous to the C switch  
> statement (lots of branching)?

I do not understand your description of C compilation: this certainly
depends a lot on the compiler and the optimization level.
OCaml does different things according to the data matched, using a
table when it is compact enough, or branches otherwise. So there is
no uniform answer, just that it is rather optimized.

> How do I find out?
> I suspect this should be quite optimized but I haven't tried dumping  
> disassembling native-compiled OCaml yet and I wonder if there's a  
> simpler approach.

No need to disassemble: you can just dump the assembler with the -S
flag. And this is probably the most instructive approach, as the
compiler itself is quite involved.

Jacques Garrigue