Comments on: Ruby Blocks and Blocks

By: Craftsmanship Tour: 8th Light - Push cx

Craftsmanship Tour: 8th Light - Push cx — Thu, 16 Dec 2010 17:36:15 +0000

[...] are fewer variables and I moved their initialization together, so your eye picks up the parallel structure and just [...]

By: Peter Harkins

Peter Harkins — Fri, 23 Jun 2006 21:33:00 +0000

Thanks for the good references. I think pointfree expresses what I was thinking of, but I dig the proc version.

By: Adz

Adz — Thu, 22 Jun 2006 14:13:23 +0000

Hmm, i think i missed your point though: “it looks something like nested fuction calls.” — !
I like to think of it as chaining rather than nested – the way that the ‘.’ evaluates from left to right.

By: Adz

Adz — Thu, 22 Jun 2006 13:53:37 +0000

“I’m compelled to write this as a block yielding to a block, though it doesn’t compile..”

Seem’s like you want to do ‘something’ with the result of line.split which is again ‘iterator’ like. No?

After all, it returns two values, which are used only in the next line.

How’s about:
“3 4\n5 6\n7 8″.each do |line|
print line.split.inject(0) { |prev, a| prev + Integer(a) }, “”
end

Although, along the lines you were thinking – you could do something like a ‘nested function call’ using a proc object (like a python lambda):

“3 4\n5 6\n7 8″.each do |line|
print proc {|a,b| Integer(a) + Integer(b) }.call(*line.split), “”
end

But i think inject is sweeter.

By: David Bremner

David Bremner — Sat, 29 Apr 2006 04:05:11 +0000

That looks like pointfree style. The Common Lisp Series library uses a similar design.

By: Peter Fein

Peter Fein — Sat, 29 Apr 2006 00:13:37 +0000

Ruby’s weird like that?

I find the book’s approach pretty hard to read.