[Haskell-cafe] Optimization with Strings ?

Alec Berryman alec at thened.net
Thu Dec 3 12:32:53 EST 2009

Emmanuel CHANTREAU on 2009-12-03 13:03:02 +0100:

> In my futur program, it use a lot of binary trees with strings (words)
> as leaf. There is just arround 1000 words and they will appear a lot of
> times. The program will possibly consume a lot of process and memory
> (it is a mathematics proover).
> I began this program in C++ but haskell has a prety good speed and
> memory footprint and is easier. But I don't know if it worth to do this
> optimization: having a dictionary to translate string words in Int.
> The answer depends on the automatic optimizations in GHC, because GHC
> could compare quickely two strings if it is the same object, so it
> depends if program generated by GHC have a dictionary (tree) of strings
> internaly. Someone knows this ?

I don't know of a library to intern strings, but it's not too hard to
implement.  I couldn't find the code I wrote to do this, but I looked
around a bit and this is about what I remember doing:


For the application I was using, interning strings did provide a
significant reduction in memory, but for whatever reason didn't help
with speed.

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