Ruby block parameters has the same name of local variable

Question

In ruby docs, there is this text:

Block parameters are actually local variables. If an existing local of the same name exists when the block executes, that variable will be modified by the call to the block. This may or may not be a good thing.

I wrote the code below to test this:

x = 0
3.upto(6) {|x| puts x}
puts x

# output are:
# 3
# 4
# 5
# 6
# 0

The variable x is not changed. Why? This is against the docs.

It wont the x in enumerator is block parameter it scope is limited inside the block only where as the other x is scope in through out the code — Viren
– Viren, Commented Oct 28, 2012 at 14:49

Dominik Honnef · Accepted Answer · 2012-10-28 14:53:02Z

8

In Ruby 1.8 and earlier, that was the case. Beginning with 1.9, block variables shadow local variables.

So, in a nutshell: The docs you are reading and the Ruby you are testing with are not of the same version.

answered Oct 28, 2012 at 14:53

Dominik Honnef

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