使用Ruby进行函数式编程

Question

Ruby has support for functional programming features like code blocks and higher-level functions (see Array#map, inject, & select).

How can I write functional code in Ruby?

Would appreciate examples like implementing a callback.

Answer 1

You could use yield

def method(foo,bar)
    operation=foo+bar
    yield operation
end

then you call it like this:

foo=1
bar=2
method(foo,bar) {|result| puts "the result of the operation using arguments #{foo} and #{bar} is #{result}"}

the code in the block (a block is basically "a chunk of code" paraphrasing ruby programmers) gets executed in the "yield operation" line, you pass the method a block of code to be executed inside the method defined. This makes Ruby pretty versatile language.

In this case yield receives an argument called "operation". I wrote it that way because you asked for a way to implement a callback.

but you could just wrote

def method()
  puts "I'm inside the method"
  yield
end

method(){puts "I'm inside a block"}

and it would output

I'm inside the method   
I'm inside a block