Marco Maggi wrote: > I am new to Larceny (10 minutes) taking a look at > larceny-0.963-bin-native-ia32-linux86)
v0.97b1 is newer and should have fewer bugs. > and I see > that this script goes into an endless loop: > > (import (rnrs) > (rnrs mutable-pairs (6))) > > (write (let ((v '(1 #f))) > (set-car! (cdr v) v) > v)) > (newline) > > when run with "scheme-script". Ikarus and the last > Ypsilon do not, so I wonder why Larceny chooses to > fill my terminal with "(1" until I hit Control-c. :) The R6RS does not specify any finite notation for circular pseudo-lists, and the R6RS also forbids extensions to its syntax that could express circular pseudo-lists. Attempts to print circular pseudo-lists in R6RS-conforming systems should result in infinite output. Ikarus and Ypsilon, like Larceny, may default to a non-conforming mode in which they have extended the R6RS notations, contrary to the R6RS's explicit language concerning extensions; if so, then Ikarus and Ypsilon should provide some kind of switch that will force them into a conforming mode, at least with regard to lexical and datum syntax. In Larceny, the #!r6rs flag serves that purpose; you might try that in Ikarus and Ypsilon. > After hitting C-c, I see that the debugger is here > and I can exit it with "q". And I am left with a prompt? Yes. It isn't a very useful prompt, since nothing is in scope, but it's a prompt. > Does it mean that I am forbidden to create a set[ug]id > script with Larceny? I think that's up to your operating system. Larceny is normally executed via a shell script, and the OS (for security) may ignore the set[ug]id attribute of shell scripts. Control-C is not the only security problem that should concern you. Although Larceny checks for accidental problems with the R6RS top-level program and libraries being executed, it does not even try to guard against malicious manipulation of the program and libraries. Will _______________________________________________ Larceny-users mailing list [email protected] https://lists.ccs.neu.edu/bin/listinfo/larceny-users
