[Haskell-cafe] Why are && and || right-associative?

Richard O'Keefe raoknz at gmail.com
Fri Apr 12 09:21:03 UTC 2019

How does the right associativity of the short-circuiting
Boolean operators in any way contradict the way that such operators work in
other languages?  These operators are associative, so a && (b && c)
necessarily has the same value and effects as (a && b) && c.  It has never
been the case that all operators in all programming languages were left
associative.  For addition and subtraction it matters; you don't want a-b+c
interpreted as a-(b+c), but not for || and not for &&.  My expectation is
that these operators should be right associative.

On Fri, 12 Apr 2019 at 14:13, Richard Eisenberg <rae at richarde.dev> wrote:

> Hi café,
> Why are && and || in the Prelude right-associative? This contradicts my
> expectation and the way these work in other languages. That said, I can't
> think of any harm in it. This came up from a question asked by a student,
> and I have no idea why the design is this way.
> Thanks,
> Richard
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