A Pythonista's Impressions of Erlang

Corrado Santoro csanto@REDACTED
Tue Jan 11 18:24:29 CET 2005

Some few words on this, from a guy who wrote projects both in Python and 

> http://llimllib.f2o.org/blog/serve/entry/erlang

> No String Type: Let me repeat this for emphasis:
 > There Is No String Type In Erlang. Arrrggggh! Why would you do this?
IMHO, I didn't suffer for a lack of a python-like string type in Erlang. 
Functions in module "lists" are quite complete and comparable to those 
of the "string" python module. If I should say that something is 
missing, I would refer to the python slicing capability, i.e.:

a="Hello, World"
a[5:-3] --> ", Wo"

 > Error messages: Erlang's error messages are totally undecipherable 
for > a newbie.
 > ** exited: {undef,[{shell_default,length,[[1,2,3],12]},
 >                    {erl_eval,do_apply,5},
 >                    {shell,exprs,6},
 >                    {shell,eval_loop,3}]} **
 > Got it?
Yes, indeed, a more verbose exception trace could be better.

 > Documentation: Most of the links to documentation on erlang.org are
 > broken.
Really? I didn't find any broken link. And you?

 > The; Punctuation. Is, Weird ->: Maybe this is one of the not sure
 > things, but I'm pretty sure I don't like some of Erlang's punctuation.
 > I don't mind the '->', but I oftentimes have to look at the docs to
 > figure out whether I should be using a ';' or a '.' to end a
 > statement.
I don't agree. The ';' has a precise semantics, because it means a logic 
"or" (like in Prolog). So using ';' to end different function clause 
means to activate this OR that clause. The '.' is a natural symbol to 
specify that a function definition (with all of its clauses) is ended.

I know that the misuse of ';' and '.' is a common cause of syntax 
errors, but similar situations also happen in C. Many students of mine 
forget to end a statement with ';', others wrongly place the ';' at the 
end of a 'for' or 'while' statement, i.e.:

for (....) ; <------!!!!!

and so on.

Finally, I would make a personal note on object-orientation. Erlang is 
not OO, but I think that such a feature---and in particular the 
inheritance---could be useful above all for beahviours.


Eng. Corrado Santoro, Ph.D.

University of Catania - Engineering Faculty
Department of Computer Science and
Telecommunications Engineering
Viale A. Doria, 6 - 95125 CATANIA (ITALY)

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