Re: Fluent programming in Ruby

[UTF-8] Wolfgang Nテ。dasi-Donner writes: 

> Please, please, please...-...don't change the syntax that
> "Ruby" and "irb" don't accept the same things, or have different
> syntactical elements for the same thing! 
> 
> Wolfgang N疆asi-Donner

First, as the person who started this thread, I'd like to point out that 
Matz has not actually asked any of us what we think about this new feature. 

The only objection I've heard to it that was mostly a matter of subjective 
dislike for fluent APIs is this issue about irb. 

I think it is solvable. (Though I don't think it needs to be solved in 
1.9.1.  We can wait for 1.9.2...) 

Modify IRB so that when it sees an expression that begins with a ., it 
treats it as method invocation on the value returned by the last line.   A 
session might look something like this: 

> "hello"
=> "hello"
> .upcase
=> "HELLO"
> .reverse
=> "OLLEH" 

The only tricky part that I see (there may be others) occurs when there is 
an assignment expression involved: 

> a = "hello"
=> "hello"
> .upcase
=> "HELLO"   # What is the value of a? 

To solve this, I think that IRB would have to defer the evaluation of 
assignment expressions until it knows that the next line will not be a 
continuation.  If the next line does not begin with a dot then the 
assignment will be done before that line is evaluated.  So if the next line 
uses the lvalue, that lvalue will have its proper value.  Seems like this 
would be transparent. 

If the lvalue is an attribute accessor with side effects visible outside of 
IRB (setting the attribute is supposed to cause a file to be created, for 
example) then there may be problems and using a semicolon would be 
necessary, I suppose. 

   David