Re: default values of 'false' in data description

[David Olofson <david@...>]

On Thursday 14 September 2006 22:00, Javier Guerra wrote:
> On Thursday 14 September 2006 2:40 pm, Paul Hudson wrote:
> >  >Or how about everything becomes an expression:
> >
> > Ah! Another step on the secret plan to turn Lua into Lisp :)
> 
> i don't remember if there was any particular objection to that
> feature.  apart from being a profound change to current grammar, of
> course. 
> 
> could anybody elaborate on the downsides of everyting (or most
> things) being an expression?

Well, there is the classical C mistake: if(a = b) ..., which compiles 
just fine, but doesn't do what the programmer (probably) intended. 
This just won't compile if an assignment does not generate a value.

Although I think "most things are expressions" can be rather handy, it 
doesn't exactly make the language safe and friendly. It allows you to 
write rather clever and compact code - but it also makes it very easy 
to write incomprehensible code, and it opens up for a bunch of 
pitfalls like the aforementioned C thing.

Meanwhile, what does it really add to a language that isn't designed 
from the ground up around the "everything is an expression" idea...?

It's not that I like languages that try to teach you "good" habits. 
(On the contrary, I'm experienced and arrogant enough to - sometimes 
incorrectly - believe that I don't need babysitting. ;-) It's just 
that some tools tend to be more dangerous than they are useful.


//David Olofson - Programmer, Composer, Open Source Advocate

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