Seems a bit like Tcl, which lets you create your own control structures like that.

I don't know a lot about Tcl, but one thing I know is said for it "everything is a string". In REBOL's it's somewaht reverse as all this live code are REBOL (Rye) values and REBOL (and Rye) have an unusual number of datatypes, REBOL 30+ (many literal types), which it uses as additional information for functions to work with, and is usefull at creating dialects

For example file-path, url and email address are distinct types in REBOL where in mosta languages are just strings.

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pwg a day ago | parent | prev [-]

Or redefine the language provided 'if' statement, in the case that one wanted to do so.

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middayc a day ago | parent [-]

You can't really redefine if because everything is a constant, but you can define if in your own context yes.

	▲	cmacleod4 21 hours ago \| parent [-]
		In Tcl you can redefine "if", or even delete it entirely if you're crazy enough :-)