[racket] [plt-scheme] Re: Typed scheme: Cannot apply expression of type Procedure, since it is not a function type

From: keydana at gmx.de (keydana at gmx.de)
Date: Sat Jun 12 12:25:16 EDT 2010

> Have you read the Guide?

Caught again :-; Well I guess that when I first got acquainted with PLT scheme (in 2008 I think), having read (or reading in parallel) SICP, the former edition of Dybvig's book on scheme (or rather, the first parts of it) and perhaps some other stuff I don't remember right now, I thought I might skip the Guide... as a general read I mean; what I've always been doing is taking the links from the Reference to the Guide as an aid to understand... Perhaps also - I don't know - the Guide has become more voluminous, more PLT-specific in the meantime? Anyway I've had a look at the contents listing now and I see it contains lots of stuff I'll probably don't know or don't REALLY know. So I'll try to find the time to read it now!
(In fact, this is always the problem with the good suggestions of what to read or do one gets on this list - if only one had more than those 30-40 minutes a day for the whole ensemble of writing scheme code, reading scheme code, reading scheme documentation, writing emails to this list :-; ... not even to mention trying to go on learning Haskell:-; )

> I'm curious to learn where precisely the hole
> in the documentation lies.

Perhaps there is none - but as you're going on in your mail yourself: People (me, at least) don't learn from documentation only. I read real books when I really want to understand concepts, get a broader view, .. and also, to learn by watching (some great books contain lots of code)

> (Racket needs a book, but it has to be the
> right kind of book.)

Having quite a big (and thick!) queue of "must read" books on my desk right now, I've had to postpone reading it to the end yet another time, but the impression I've had from the first 200 (300?) pages of "Real World Haskell" was quite positive: It explains the core language, it gives a motivating introduction to functional programming (I remember being on vacation, without a laptop, when I read the section where it shows how to formulate functions in terms of foldl & foldr, and I tried doing the same in scheme in my head :-; ), but afterwards it really goes on to solving "real-world problems" in Haskell... 
I think a book on Racket might be a bit like this. All the necessary stuff, Racket has already... the web server, the FFI, the network functionalities and and and... just present it not as a reference, but more of a tutorial / "by example" kind of thing?

Ciao, Sigrid

> N.

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