[Haskell-cafe] What is a "simple pattern binding"?

Paterson, Ross R.Paterson at city.ac.uk
Sun Jun 26 10:31:05 CEST 2011


> If this is the case, then multiple sentences in the 2010 report don't
> make sense, though the way in which they don't make sense sort of
> depends on what "simple pattern binding" means.

Indeed, the Report has two problems:

Sections 4.4.3.2 and 4.5.5 have different definitions of "simple pattern".
This has been there since section 4.5.5 (Monomorphism Restriction) was
added in Haskell 1.1.  But then the only technical use of the term is
in section 4.5.5.

When the definition of declaration group (section 4.5.1) was changed in
Haskell 2010 to break dependencies on type signatures, Rule 1 of the
Monomorphism Restriction (section 4.5.5), while not incorrect, became
partially redundant and overly complex.  It could have been simplified
along the lines you describe.



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