langreiter.com plain, simple: comment-2007-10-23-1

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comment-2007-10-23-1

CREATED BY earl • LAST EDITED BY earl 6269 days AGO

Thanks for the nice Logo link. Ian tackles a lot of what is interesting about Logo-the-language and almost everything of it is directly related to REBOL as well. Comparing those two languages, one of the main parts to take away is that Logo uses dynamic scope and, as Ian says, "a nice side effect of dynamic scoping is that EVAL works pretty well."

A nicely-working EVAL is pretty essential for Logo's lack of special forms but dynamic scoping is widely disregarded these days (rightly so). This tension needs to be resolved by any modern language in Logo's tradition. Either by acknowledging a dynamically scoped nature up-front or by clearly stating an alternate scoping behaviour (and the corresponding EVAL semantics). Unfortunately, with REBOL, neither is the case.