[Haskell-cafe] Haskell symbol ~

Brandon S. Allbery KF8NH allbery at ece.cmu.edu
Wed Aug 27 14:47:13 EDT 2008

On 2008 Aug 27, at 14:23, Maurí cio wrote:
> What does '~' mean in Haskell? I
> read in haskell.org/haskellwiki/Keywords
> that “(...) Matching the pattern ~pat
> against a value always suceeds, and
> matching will only diverge when one of
> the variables bound in the pattern is
> used.” Isn't that true for any
> variable, due to lazyness?

Only in let-patterns; others, including case expressions and top level  
definitions, are strict (which is in fact the normal way to force a  

brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allbery at kf8nh.com
system administrator [openafs,heimdal,too many hats] allbery at ece.cmu.edu
electrical and computer engineering, carnegie mellon university    KF8NH

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