argument ordering

Johannes Waldmann waldmann at
Mon Aug 22 09:43:47 EDT 2005

Christian Maeder wrote:
> Okasaki, C. DR EECS wrote:
>>   insert 1 a $ insert 2 b $ insert 3 c dict
> A further argument for this notation is its close resemblance to the
> notation with function composition:
> insert 1 a . insert 2 b . insert 3 c $ dict

... of course keeping in mind that that's exactly the "wrong" way
to compose functions. See any algebra textbook for
definition of (f . g) (namely, first apply f, then apply g)

1. flow of information should be from left to right
2. consistency with composition of relations.

of course you could say that even writing f(x) is "wrong" (see item 1)
and there are indeed books that write  xf  instead
(e. g. Sakarovitch: Theorie des Automates - but then even he makes
exceptions, e. g. he uses prefix notation for  lim, sin, dom ... :-)

on the other hand I know at least on textbook that has the relational
composition the wrong way around, obviously in order to make it agree
with the wrong functional composition.

best regards,
-- Johannes Waldmann -- Tel/Fax (0341) 3076 6479/80 --
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