Re: Preliminary Haskell 1.3 report now available
Thomas Hallgren [EMAIL PROTECTED] writes: In the syntax for labeled fields (records) the symbol - is chosen as the operator used to associate a label with a value in constructions and patterns: [...] According to a committee member, there were no convincing reasons why - was chosen. Other symbols, like = and := were also considered. I support Thomas Hallgen's suggestion that `=' be used instead. Another reason, in addition to the two he mentioned, is that the `-' symbol is very unintuitive when used for pattern matching, because the arrow is in the *opposite* direction to the data-flow. I find this very confusing. -- Fergus Henderson | Designing grand concepts is fun; [EMAIL PROTECTED] | finding nitty little bugs is just work. http://www.cs.mu.oz.au/~fjh | -- Brooks, in "The Mythical Man-Month". PGP key fingerprint: 00 D7 A2 27 65 09 B6 AC 8B 3E 0F 01 E7 5D C4 3F
Re: Preliminary Haskell 1.3 report now available
I always favoured `=' over `-', but I don't care much. -- Lennart
Re: Preliminary Haskell 1.3 report now available
Thomas Hallgren [EMAIL PROTECTED] writes:
In the syntax for labeled fields (records) the symbol - is chosen
as the operator used to associate a label with a value in
constructions and patterns:
[...]
According to a committee member, there were no convincing reasons
why - was chosen. Other symbols, like = and := were also considered.
I support Thomas Hallgen's suggestion that `=' be used instead.
Another reason, in addition to the two he mentioned, is that the `-'
symbol is very unintuitive when used for pattern matching, because the
arrow is in the *opposite* direction to the data-flow. I find this
very confusing.
Indeed, a couple of reasons I find convincing myself:
1 - SML uses '=' too, therefore it is one less problem for people
moving to/from SML/Haskell.
2 - The '-' notation always reminds me of list comprehensions,
e.g. at first sight if I see an expression like
R{v - [1..10]}
I could think v is an integer (taken from [1..10]) when it is actually a list.
the following expression is also confusing:
[R{v - [1..x]} | x - [1..10]]
(defines a list of records)
An expression using records on the rhs of the '|' should be even more interesting
(and useful for obfuscated Haskell competitions).
The same applies for records with fields defined with list comprehensions.
Andre.
Andre SantosDepartamento de Informatica
e-mail: [EMAIL PROTECTED] Universidade Federal de Pernambuco
http://www.di.ufpe.br/~alms CP 7851, CEP 50732-970, Recife PE Brazil
Preliminary Haskell 1.3 report now available
Announcing a preliminary version of the Haskell 1.3 report. The Haskell 1.3 report is nearly complete. All technical issues appear to be resolved and the report is nearly ready. The report will be finalized April 19. Any comments must be submitted by April 15. We do not anticipate making any serious technical changes is the current version. The report is being made available both on the web and as a .dvi file. A summary of changes made in the Haskell 1.3 report can be found in http://www.cs.yale.edu/HTML/YALE/CS/haskell/haskell13.html This has pointers to the html version of the report. The dvi file is available via anonymous ftp at ftp://haskell.cs.yale.edu/pub/haskell/report/new-report.dvi.gz Send comments or questions to [EMAIL PROTECTED]
