Re: [Chicken-users] how to unintern a symbol
On Mon, Feb 02, 2015 at 11:34:05AM -0800, Dan Leslie wrote: Is that a function composition function I spy? I wasn't aware of such a thing in R5RS or R7RS, is it a chicken extension or a part of one of the Unity libraries? It's a CHICKEN extension :) There's also compose for when the functions accept/return more than one value (o is a more efficient version for single arg). Cheers, Peter signature.asc Description: Digital signature ___ Chicken-users mailing list Chicken-users@nongnu.org https://lists.nongnu.org/mailman/listinfo/chicken-users
Re: [Chicken-users] how to unintern a symbol
Peter Bex scripsit: I wasn't aware of that CL behaviour. IIUC that's actually conflating two different things: creating an uninterned symbol and unbinding an interned symbol. I don't know of a way to unbind a variable through Scheme, but you can set the symbol's value slot (0) to C_SCHEME_UNBOUND in C. This has to go with the warnings Don't try this at home, and this voids your warranty. :) Actually, neither of those things is what CL `unintern` does, though I can see how people might come to believe that. What it does is to remove an existing symbol from the symbol table. The symbol maintains its properties, including its value, but any future attempt to refer to a symbol of the same name will create an entirely new object, since lookup in the symbol table will fail (and of course this new symbol is undefined). To put things another way, `unintern` mutates its argument from interned to uninterned. It's a dangerous thing to do, because it corrupts Scheme/Lisp read-write equivalence. -- John Cowan http://www.ccil.org/~cowanco...@ccil.org If I have seen farther than others, it is because I am surrounded by dwarves. --Murray Gell-Mann ___ Chicken-users mailing list Chicken-users@nongnu.org https://lists.nongnu.org/mailman/listinfo/chicken-users
Re: [Chicken-users] readline egg v2.0 feedback
Just pushed 3.0 out the door. Please let me know if it isn't regnoized as the latest version and I'll bump it up to 3.1. And let me know if yall come across any bugs. It introduces the following toplevel commands: * ,rl-!! o Similar to Bash's /!!/, it evaluates the previous line. * ,rl-clh o Clears the history list for the current session * ,rl-savhist o Enables/disables saving history for the current session on exit * ,rl-rec o Enables/disables recording history for the current session * ,rl-rd o Reads a file's contents into the history list for the current session * ,rl-vi o sets the current editing mode to Vi emulation * ,rl-emacs o sets the current editing mode to Emacs emulation (the One True Editing-Mode) :P The following functions have been added: * last-history-line o Returns the previous line in history as either a string or as-is * eval-last-history-line o The function behind /,rl-!!/ * variables o dumps GNU Readline's variable state, such as what editing mode it is in and etc. Most of the functions added by v2.0 have been removed in 3.0; this, unfortunately, includes the history searching functions.//However, the history searching functions will be added back again in the next (proper) release, which should be 3.1. On 01/27/2015 11:10 AM, Evan Hanson wrote: Hi Alexej, My tuppence: On 2015-01-27 4:01, Alexej Magura wrote: I don't think I'll use the toplevel-command stuff after all: I can't promise that the toplevel symbols readline exports won't get overwritten, and I'm not entirely sure readline has any business providing private toplevel symbols that are only applicable to it. It might confuse less-experienced users*, for one, and for another there's the already mentioned possibility of symbol collision, unless somebody more knowledge on this subject can prove otherwise. It's your call of course, but I'd urge you not to let this stop you if you'd otherwise like to provide this feature. If all commands are prefixed by rl, for example, the ease of use would outweight any risk of conflicts, IMO. After all, extensions are expected to provide commands; that's part of what the feature's there for. chicken-doc uses it to great effect, for example. Perhaps you could address the concern that users will mistake readline-provided commands for builtins by adding a note that they come from the readline egg to the commands' help strings? Cheers, Evan ___ Chicken-users mailing list Chicken-users@nongnu.org https://lists.nongnu.org/mailman/listinfo/chicken-users
Re: [Chicken-users] how to unintern a symbol
On Mon, Feb 02, 2015 at 10:51:26AM -0700, Alexej Magura wrote: Does Chicken have anything comparable to Common Lisp's /unintern/? I thought that it might be under /##sys/, since other features present in Common Lisp, but absent in Chicken are available under that namespace, but it doesn't seem to be provided by that module/namespace. There's string-uninterned-symbol, which is even documented, right below gensym: http://wiki.call-cc.org/man/4/Unit%20library#string-uninterned-symbol If you have a symbol you want to unintern, you can get its string and create an uninterned symbol from that: (define unintern (o string-uninterned-symbol symbol-string)) (eq? (unintern 'foo) 'foo) = #f Cheers, Peter signature.asc Description: Digital signature ___ Chicken-users mailing list Chicken-users@nongnu.org https://lists.nongnu.org/mailman/listinfo/chicken-users
Re: [Chicken-users] how to unintern a symbol
AFAICT that just defines a symbol to itself, and only then if you run: (define foo 1) (define foo (unintern 'foo)) (eq? foo |foo|) = #t But, as I said, that only defines 'foo as |foo|: it doesn't /undefine/ the symbol, and it needs to have side-effects, since the CL /unintern/ AFAIK effects the targeted package, or in our case module. After uninterning /foo/, if I were to enter foo into the REPL to be evaluated, it would throw an unbound variable exception. On 02/02/2015 11:31 AM, Peter Bex wrote: On Mon, Feb 02, 2015 at 10:51:26AM -0700, Alexej Magura wrote: Does Chicken have anything comparable to Common Lisp's /unintern/? I thought that it might be under /##sys/, since other features present in Common Lisp, but absent in Chicken are available under that namespace, but it doesn't seem to be provided by that module/namespace. There's string-uninterned-symbol, which is even documented, right below gensym: http://wiki.call-cc.org/man/4/Unit%20library#string-uninterned-symbol If you have a symbol you want to unintern, you can get its string and create an uninterned symbol from that: (define unintern (o string-uninterned-symbol symbol-string)) (eq? (unintern 'foo) 'foo) = #f Cheers, Peter ___ Chicken-users mailing list Chicken-users@nongnu.org https://lists.nongnu.org/mailman/listinfo/chicken-users
[Chicken-users] how to unintern a symbol
Does Chicken have anything comparable to Common Lisp's /unintern/? I thought that it might be under /##sys/, since other features present in Common Lisp, but absent in Chicken are available under that namespace, but it doesn't seem to be provided by that module/namespace. ___ Chicken-users mailing list Chicken-users@nongnu.org https://lists.nongnu.org/mailman/listinfo/chicken-users
Re: [Chicken-users] how to unintern a symbol
On Mon, Feb 02, 2015 at 11:55:12AM -0700, Alexej Magura wrote: AFAICT that just defines a symbol to itself, and only then if you run: (define foo 1) (define foo (unintern 'foo)) (eq? foo |foo|) = #t But, as I said, that only defines 'foo as |foo|: it doesn't /undefine/ the symbol, and it needs to have side-effects, since the CL /unintern/ AFAIK effects the targeted package, or in our case module. After uninterning /foo/, if I were to enter foo into the REPL to be evaluated, it would throw an unbound variable exception. I wasn't aware of that CL behaviour. IIUC that's actually conflating two different things: creating an uninterned symbol and unbinding an interned symbol. I don't know of a way to unbind a variable through Scheme, but you can set the symbol's value slot (0) to C_SCHEME_UNBOUND in C. This has to go with the warnings Don't try this at home, and this voids your warranty. :) Cheers, Peter signature.asc Description: Digital signature ___ Chicken-users mailing list Chicken-users@nongnu.org https://lists.nongnu.org/mailman/listinfo/chicken-users
Re: [Chicken-users] how to unintern a symbol
Is that a function composition function I spy? I wasn't aware of such a thing in R5RS or R7RS, is it a chicken extension or a part of one of the Unity libraries? Thanks! -Dan Peter Bex pe...@more-magic.net writes: On Mon, Feb 02, 2015 at 10:51:26AM -0700, Alexej Magura wrote: Does Chicken have anything comparable to Common Lisp's /unintern/? I thought that it might be under /##sys/, since other features present in Common Lisp, but absent in Chicken are available under that namespace, but it doesn't seem to be provided by that module/namespace. There's string-uninterned-symbol, which is even documented, right below gensym: http://wiki.call-cc.org/man/4/Unit%20library#string-uninterned-symbol If you have a symbol you want to unintern, you can get its string and create an uninterned symbol from that: (define unintern (o string-uninterned-symbol symbol-string)) (eq? (unintern 'foo) 'foo) = #f Cheers, Peter ___ Chicken-users mailing list Chicken-users@nongnu.org https://lists.nongnu.org/mailman/listinfo/chicken-users -- -Dan Leslie ___ Chicken-users mailing list Chicken-users@nongnu.org https://lists.nongnu.org/mailman/listinfo/chicken-users
