Ruby Print Inject Do Syntax

Question

Why is it that the following code runs fine

p (1..1000).inject(0) { |sum, i|
    sum + i
}

But, the following code gives an error

Answer 1

The problem is with the p at the beginning. If you omit these you'll see that both work fine:

# Works!
[5, 6, 7].inject(0) do |sum, i| # Correctly binds to `inject`.
  sum + i
end

# Works too!
[5, 6, 7].inject(0) { |sum, i|  # Correctly binds to `inject`.
  sum + i
}

But this won't work:

# Kablammo! "p" came first, so it gets first dibs on your do..end block.
# Now inject has no block to bind to!
p [5, 6, 7].inject(0) do |sum, i|   # Binds to `p` -- not what you wanted.
  sum + i
end