Why is a separator not required in `for i do cmd; done` [duplicate]

Question

for i do echo $i; done

How is this even legal? (I would expect it to be written with an extra semi-colon for i; do echo $i; done) It works in bash, dash, zsh, and ksh. The standard (by which I mean http://pubs.opengroup.org/onlinepubs/9699919799/) states:

The for loop requires that the reserved words do and done be used to
delimit the sequence of commands.  The format for the for loop is as follows:

    for name [ in [word ... ]]
    do
        compound-list
    done

So clearly when "in word" is omitted, do is serving as a separator. So the implication seems to be that the separator (the newline) after the [ in [word .. ]] actually belongs inside the closing right bracket. Can someone point to anything in the standard which justifies this (IMO) horrible abuse of the language?

Answer 1

If you look at the GNU man page, you see the loop has this syntax:

for

    The syntax of the for command is:

    for name [ [in [words …] ] ; ] do commands; done

So as you can see the extra semi-colon is part of the optional section.

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The linux-die man page states the same.