Difference between revisions of "Singleton list confusion"
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Why do Haskell newcomers frequently believe, that list variables must be enclosed in brackets? |
Why do Haskell newcomers frequently believe, that list variables must be enclosed in brackets? |
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People sometimes write argument patterns like <hask>[x]</hask>, hoping that <hask>x</hask> will assume all values of a list successively. |
People sometimes write argument patterns like <hask>[x]</hask>, hoping that <hask>x</hask> will assume all values of a list successively. |
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| − | Maybe |
+ | Maybe they expect some kind of [[list comprehension]]. |
| + | However, if there wouldn't be a special [[list notation]] and if there wouldn't be the special syntax for the list type constructor (thus we must write <hask>[a]</hask> instead of <hask>List a</hask>), |
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| + | then there would be certainly less confusion. |
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Revision as of 07:07, 11 April 2008
Why do Haskell newcomers frequently believe, that list variables must be enclosed in brackets?
People sometimes write argument patterns like [x], hoping that x will assume all values of a list successively.
Maybe they expect some kind of list comprehension.
However, if there wouldn't be a special list notation and if there wouldn't be the special syntax for the list type constructor (thus we must write [a] instead of List a),
then there would be certainly less confusion.
See for example Haskell-Cafe about testing for same characters in lists of strings, Pattern match failure