Thanks Stephen, that helps.
On Sun, Apr 11, 2010 at 1:58 PM, Stephen Tetley
Hello
There is no semantic implication of the difference.
http://haskell.org/onlinereport/syntax-iso.html
The Haskell syntax allows multiple declarations within a single let expression:
exp10 -> ... | let decls in exp
where decls is a list of declarations, (braces and colons can be replaced by layout):
decls -> { decl1 ; ... ; decln }
As a let ... in ... is an expression you can choose to write a list of declarations as nested let instead as you did in the second version.
From the original description of GHC intermediate form 'core' [1] page 3 shows that GHC chooses to desugar a let expression with a list of decls into nested singular let expressions, though this might have changed and also I might be misreading how GHC core distinguishes recursive let declarations which do appear as lists.
Best wishes
Stephen
[1] An External Representation for the GHC Core Language (DRAFT for GHC5.02) Andrew Tolmach and the GHC Team
GHC doesn't define Haskell of course... _______________________________________________ Beginners mailing list Beginners@haskell.org http://www.haskell.org/mailman/listinfo/beginners
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