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What do things like [string!] and [any-block!] in a function specification block mean?

April 26, 2017block function mean specification String

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What do things like [string!] and [any-block!] in a function specification block mean?

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Function arguments followed by one or more datatype identifiers in a block denote a specific constraint on that argument to a function. For instance, the following header: some-func: func [value [money!]] […] means SOME-FUNC takes one argument assigned to VALUE. The function will return an error if it is supplied an argument other than a money type. See the REBOL/Core User’s Guide Functions chapter for more.