variable assignment - var vs := in Go

Question

In the Go web server example here: http://golang.org/doc/effective_go.html#web_server

The following line of code works

var addr = flag.String("addr", ":1718", "http service address")

but changing it to

addr := flag.String("addr", ":1718", "http service address")

is a compilation error. Why? Does it have anything to do with the face that the return type of the function is *string instead of string? What difference does that make?

UPDATE: Thanks for pointing out that := is not allowed at the top level. Any idea why this inconsistency is in the spec? I don't see any reason for the behaviour to be different inside a block.

Answer 1

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