Implementing Set#to_proc and Hash#to_proc in Ruby | Hacker News Reader

Implementing Set#to_proc and Hash#to_proc in Ruby

mudge.name

28 pointsmudgemeister2 comments

FYI - the ampersand syntax is only in function calls, so the following will fail:

    &set.call(1)

Whereas this will not:

    (1..30).select(&set)

Generally speaking, & is syntactic sugar for .to_proc, but only within function calls.

> & is syntactic sugar for .to_proc, but only within function calls

It's not exactly that. & is the syntax to pass a variable as a block to a method. And ruby will implicitly call to_proc on the object it receive as a block.

I know it seems pedantic, but there is a difference.

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