What is the difference between an “interned” and an “uninterned” symbol. Is it only Racket that has uninterned symbols or do other dialects of scheme or lisp have them?
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What is the difference between an “interned” and an “uninterned” symbol. Is it only Racket that has uninterned symbols or do other dialects of scheme or lisp have them?
Interned symbols are
eq?if and only if they have the same name. Uninterned symbols are noteq?to any other symbol, so they are a kind of unique token with an attached string. Interned symbols are the kind that are produced by the default reader. Uninterned symbols can be used as identifiers when generating code in a macro, such an identifier cannot be shadowed by any other identifier. Most Lisp dialects have this concepts, in Scheme it is rarer, since hygienic macros are supposed to reduce its usefulness.