This site is a static rendering of the Trac instance that was used by R7RS-WG1 for its work on R7RS-small (PDF), which was ratified in 2013. For more information, see Home. For a version of this page that may be more recent, see SetUndefinedVariable in WG2's repo for R7RS-large.

Set­Undefined­Variable

cowan
2014-12-28 10:27:36
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Attempting to set an unbound variable

Racket, Gauche, MIT, Gambit, Bigloo, Scheme48/scsh, Guile, SISC, Chibi, SCM, Ypsilon, NexJ, STklos, KSi, SigScheme, Shoe, TinyScheme, Scheme 9, Dream, S7, Schemik, Elk, UMB, Sizzle, Spark, Dfsch, Inlab, Sagittarius complain about the attempt to use set! on an unbound variable.

Chicken, Kawa, Chibi, Chez, Ikarus/Vicare, Larceny, Mosh, XLisp, Rep, VX, Llava, Femtolisp do not.

Oaklisp, SXM print a warning but allow it.

Owl Lisp doesn't have variable assignment.