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 ImmediateStringsCoalesced in WG2's repo for R7RS-large.


2012-06-09 06:41:41

Are immediate strings coalesced?

Asked to evaluate (let ((a "hello") (b "hello") (eq? a b)), Racket, Gauche, MIT, Gambit, Chicken, Bigloo, SISC, Chibi, Chez, SCM, Ikarus/Vicare, Mosh, KSi, SigScheme, TinyScheme, Scheme 9, Dream, Scheme 7, BDC, XLisp, Rep, Schemik, Elk, UMB, Oaklisp, and Owl Lisp all return #f.

Scheme48/scsh, Guile, Kawa, Larceny, Ypsilon, IronScheme, NexJ, STklos, Shoe, RScheme, JScheme, VX return #t.

There may be some false negatives here, because an implementation might coalesce literals in the compiler but not at the REPL.