From: Hal Fulton <hal9000@...>
Date: 2006-10-19T08:55:27+09:00
Subject: Re: My first feeling of Ruby

Florent Guiliani wrote:
> 
> Why #test doesn't work for local variables? It would be more logic. It's 
> my point of view. We can have both #test and #{test} working.
> 

For one thing, test could just as easily be a method name. This
might lead people to think that the parameters followed it in
the string.

Things such as #$foo and #@foo are special cases. A single char
tells us that it's a simple variable.

The general case is #{...} and can be any arbitrary expression.


> Second thing:
> =============
> hastables is using a mix of {} and []. Always using {} or [] (but not 
> both) for hastable would be "errorless".

Conflict with block syntax. You can't say hash {"A"} meaningfully.
In fact, I'm not certain why that returns an integer.


Hal



> Actually {} for initialisation:
> irb(main):150:0> hash = { "A"=>1 , "B"=>2 }
> => {"A"=>1, "B"=>2}
> 
> [] for reading:
> irb(main):152:0> hash["A"]
> => 1
> 
> If you go wrong:
> irb(main):156:0> hash{"A"}
> => 537984250
> irb(main):154:0> hash = [ "A"=>1 , "B"=>2 ]
> => [{"A"=>1, "B"=>2}]
> 
> I would prefer an error or warning. The last line means I can omit {}? 
> so let's go on:
> 
> irb(main):155:0> hash = "A"=>1 , "B"=>2
> SyntaxError: compile error
> (irb):155: parse error, unexpected tASSOC, expecting $
> hash = "A"=>1 , "B"=>2
>             ^
>         from (irb):155
>         from :0
> irb(main):156:0>
> 
> Hmm why [ "A"=>1 , "B"=>2 ] silently produce [{"A"=>1, "B"=>2}] ?
> 
> my 2c,
> Florent,
>