[Haskell-cafe] commending "Design concepts in programming languages"

Wolfgang Jeltsch g9ks157k at acme.softbase.org
Tue May 12 07:41:06 EDT 2009

Am Freitag, 8. Mai 2009 14:31 schrieb Daniel Fischer:
> Though I had no contact with algebraists in the 1980s,

I also hadn’t. However, nowadays I have contact with someone who was an 
algebraist in the 1980s. It’s my boss (professor), by the way. :-) 

> > I think, also category theorists often wrote (write?) composition with
> > the first morphism on the left, i.e., “the other way round”.
> Yeah, I heard that, too. It's a field where the advantages of postfix
> notation show clearly and a young one, so for them it was relatively easy
> to switch.

However, I fear that all those other mathematicians who define
f . g = \x -> f(g(x), have made the category theorists switch to this 
suboptimal notation (first morphism on the right). At least, I cannot 
remember seeing the other notation (first morphism on the left) in category 
theory literature so far. It’s just that my above-mentioned professor told me 
that category theorists would use the first-morphism-on-the-left notation.

Best wishes,

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