On Aug 4, 2006, at 1:12 PM, Martin Percossi wrote:
Hi, I'm wondering what the rationale was for not allowing
capitalized variable names (and uncapitalized type names and
constructors). I can only think of two arguments, and IMHO both of
them are bad:
1. Enforces a naming convention. Fine - but my view is that this
doesn't belong in the language definition (it belongs in the user's
coding standards). I get annoyed, for example, that when I write
code that manipulates matrices and vectors, I can't refer to the
matrices with capital letters as is common in the literature.
This is occasionally irritating.
And to anyone who says that it's good to enforce naming
consistency, I have this to say: Any language that requires me to
learn about category theory in order to write imperative code
should treat me like an adult when it comes to the naming of
variables as well. ;-)
2. It makes it easier to write the compiler. I don't think I need
to explain why this is bad...
Eh? I'm not convinced this is a bad reason. It obviously needs to
be balanced against other competing factors, but ease of
implementation should always a consideration when designing a language.
3. It removes a whole class of possible ambiguities from the
language. You the programmer (and the compiler, as an added bonus)
can always identify the syntactic class of an identifier from _purely
local_ context.
Suppose I remove the case restriction. Is the following a pattern
match or a function definition? Is M a variable or a data constructor?
let f x M = z M in ....
You can't tell! Worse, it could change depending on what identifiers
are in scope. It could happen that you import a module and it
silently causes your function definition to change to a pattern
match. The situation is similar with type classes and type
variables. You could magically end up with an instance declaration
that is less polymorphic than you expect (if you have extensions
turned on).
I imagine that someone is just itching to "sort me out". Do your
worst! ;-)
Thx
Martin
Rob Dockins
Speak softly and drive a Sherman tank.
Laugh hard; it's a long way to the bank.
-- TMBG
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