[Haskell] writeFile for a looong string

Simon Marlow simonmar at microsoft.com
Thu Jul 14 07:39:16 EDT 2005

On 14 July 2005 10:08, Johannes Waldmann wrote:

> I am writing a long string (several MByte) to a file,
> with   writeFile fname ( render d )
> where d :: Text.PrettyPrint.HughesPJ.Doc
> I wonder what happens internally
> (when compiled with ghc -O, if that matters)
> Will the string be in memory completely
> before it is actually written?

No, it should be streamed to the output in constant space, as long as
the String can be evaluated lazilly.


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