(Moved to haskell-cafe) Syntacticly, -x parses as 0-x. That is, there is only one - operator and the "0" is filled in when it is encountered in a unary position. Thus -3 ^ 2 translates to 0 - 3 ^ 2 There were many arguments on either side of this debate but I would have to dig deep into the archives to remember what they were. This is certainly a potential source of confusion! Anyway, experienced Haskellers always add parens around unary minus to avoid any ambiguity: (-3) ^ 2 John
John Peterson:
Syntacticly, -x parses as 0-x. That is, there is only one - operator and the "0" is filled in when it is encountered in a unary position. Thus
-3 ^ 2 translates to 0 - 3 ^ 2
There were many arguments on either side of this debate but I would have to dig deep into the archives to remember what they were. This is certainly a potential source of confusion!
Anyway, experienced Haskellers always add parens around unary minus to avoid any ambiguity: (-3) ^ 2
Hmm, any reason not to parse -x as (0-x) rather than 0-x? Then, -3 ^ 2 would translate to (0-3) ^ 2. Björn Lisper
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Bjorn Lisper -
John Peterson