these things are very much a matter of taste. what does "effective" mean with respect to syntax? for instance, lispers will argue that their syntax is effective because of the things it lets you do, but that's orthogonal to whether it's actually a pleasant syntax to program in, which comes down to personal taste[1]. likewise, i love mlish syntax, but opa, a language steeped in ml semantics, nonetheless switched to something more javascripty for their main syntax because it proved more popular[2]. and read through the wrangling over ruby versus python sometime - the two languages are very similar under the hood, but their respective syntaxes are one of the things proponents of each language complain about when they have to use the other.
[1] as larry wall famously said, "lisp has all the visual appeal of oatmeal with fingernail clippings mixed in."
It takes a lot of chutzpah for Larry Wall to say anything critical about Lisp syntax. Larry Wall. Come on.
I'm not the author of the comment above, but I think Erlang's syntax is effective in that it strongly emphasizes computation by pattern matching. If you write very imperative code in it (as people tend to, coming from Ruby or what have you), yes, it will look gnarly. Good Erlang code looks qualitatively different. There are pretty good examples of hairy, imperative Erlang code being untangled in this blog post: http://gar1t.com/blog/2012/06/10/solving-embarrassingly-obvi...
The . , ; thing is a bit of a hack, admittedly -- I suspect that comes from using Prolog's read function to do parsing for the original versions of Erlang (which was a Prolog DSL), and reading every clause of a function definition at the same time. Prolog ends every top-level clause with a period, not "; ; ; ; .". (Not sure, but a strong hunch, supported by Erlang's history.) I got used to it pretty quickly, though.
As in Prolog ',' and ';' are separators: ',' behaves like an and, first do then and then do this (as in Prolog); while ';' is an or, do this clause or do this clause (again as in Prolog). '.' ends something, in this case a function definition. Erlang's functions clauses are not the same as Prolog's clauses which explains the difference.
It is very simple really, think of sentences in English and it all becomes trivially simple.How many sentences end in a ';'?. And you almost never need to explicitly specify blocks.
Sort of. The syntax evolved at the same time we were moving from Prolog onto our own implementation, which forced us to write our own parser and not rely on the original Prolog one. The biggest syntax change came around 1991, since then it has been mainly smaller additions and adjustments.
Anyways, my experience is that all languages will get people criticizing them. And, in my experience, those kinds of criticisms should almost always be categorized as "does not want to talk about language FOO" and a proper response is probably something like "if you don't want to give that subject the respect it deserves, let's change the subject to something you find interesting".
Erlang syntax maybe jarring but one benefit of it is there is actually very little syntax relative to languages like Java, C++, Python. There isn't that much to hold in your head. I can switch between Erlang and another language pretty effortlessly because the context switch is so small.
[1] as larry wall famously said, "lisp has all the visual appeal of oatmeal with fingernail clippings mixed in."
[2] http://blog.opalang.org/2012/02/opa-090-new-syntax.html