Re: [Chicken-users] retrieving a structure's symbol name
On Thu, Jul 25, 2019 at 07:36:04AM +0200, Marco Maggi wrote: > I am writing a library that mimics R6RS records. Every R6RS record-type > can be associated to a unique identifier (UID), which is a symbol. > Defining the same record-type in multiple modules is fine, under the > correct conditions. > > Using the UID as struct type name, and so implementing records as > simple CHICKEN structs, seems an efficient way to do it. I had a quick look at the R6RS page and god that shit is ugly :) But you're right, using these low-level constructors seems the best way to do this. Maybe you can use gensyms or uuids for the record names. uuids probably work better if you later want to generate a types database for the library. Cheers, Peter signature.asc Description: PGP signature ___ Chicken-users mailing list Chicken-users@nongnu.org https://lists.nongnu.org/mailman/listinfo/chicken-users
Re: [Chicken-users] retrieving a structure's symbol name
Peter Bex wrote: >> If I define my own record-type >> constructor, and I want to use the built-in record printers facilities: >> is CHICKEN expecting me to qualify the name with the module? The >> symbols I want to use are expected to be unique... > No, you can use unqualified symbols. We still do that in core itself too, > for SRFI-4 vectors and for ports and so on. But this is really low-level > stuff, and there's usually a better way. What exactly are you trying to > accomplish? I am writing a library that mimics R6RS records. Every R6RS record-type can be associated to a unique identifier (UID), which is a symbol. Defining the same record-type in multiple modules is fine, under the correct conditions. Using the UID as struct type name, and so implementing records as simple CHICKEN structs, seems an efficient way to do it. -- Marco Maggi ___ Chicken-users mailing list Chicken-users@nongnu.org https://lists.nongnu.org/mailman/listinfo/chicken-users
Re: [Chicken-users] retrieving a structure's symbol name
On Wed, Jul 24, 2019 at 07:22:45PM +0200, Marco Maggi wrote: > Mh. If I understand correctly this is to avoid collisions for the > record printers, and stuff like that. It is to avoid collisions for all accessors and predicates. If I define a record type X of 2 slots in module A, and in module B, I define a record type also called X of 1 slot, then "X?" would return #t for both records. And if I want to access the second slot of the record in module A, but pass in an X of module B (which has only one slot), this will cause an unsafe memory access. That's because we can't safely check first if the record is of the correct type. > If I define my own record-type > constructor, and I want to use the built-in record printers facilities: > is CHICKEN expecting me to qualify the name with the module? The > symbols I want to use are expected to be unique... No, you can use unqualified symbols. We still do that in core itself too, for SRFI-4 vectors and for ports and so on. But this is really low-level stuff, and there's usually a better way. What exactly are you trying to accomplish? Cheers, Peter signature.asc Description: PGP signature ___ Chicken-users mailing list Chicken-users@nongnu.org https://lists.nongnu.org/mailman/listinfo/chicken-users
Re: [Chicken-users] retrieving a structure's symbol name
Peter Bex wrote: > On Wed, Jul 24, 2019 at 03:49:13PM +0200, Marco Maggi wrote: >> Ciao, >> I know that it is dirty, but is it possible to retrieve the symbol >> name of a structure from the block object? If I create a structure >> with: >>(define (make-it) >> (##sys#make-structure 'spiffy)) >>(define O >> (make-it)) >> can I extract "spiffy" from the structure object bound to "O"? I >> searched "library.scm" in CHICKEN's 5.1.0 source without success. > You can access slot 0 to get it: > (##sys#slot (##sys#make-structure 'foo) 0) => foo Yes! Damn, I already knew about it... > And it will be namespaced with the module if it is defined in a module. Mh. If I understand correctly this is to avoid collisions for the record printers, and stuff like that. If I define my own record-type constructor, and I want to use the built-in record printers facilities: is CHICKEN expecting me to qualify the name with the module? The symbols I want to use are expected to be unique... Thanks. -- Marco Maggi ___ Chicken-users mailing list Chicken-users@nongnu.org https://lists.nongnu.org/mailman/listinfo/chicken-users
Re: [Chicken-users] retrieving a structure's symbol name
On Wed, Jul 24, 2019 at 03:49:13PM +0200, Marco Maggi wrote: > Ciao, > > I know that it is dirty, but is it possible to retrieve the symbol > name of a structure from the block object? If I create a structure > with: > >(define (make-it) > (##sys#make-structure 'spiffy)) > >(define O > (make-it)) > > can I extract "spiffy" from the structure object bound to "O"? I > searched "library.scm" in CHICKEN's 5.1.0 source without success. You can access slot 0 to get it: (##sys#slot (##sys#make-structure 'foo) 0) => foo There's no official way to get at it. But, if you are on CHICKEN 5.1 the define-record-type type name will contain it: #;3> (define-record-type foo (make-foo) foo?) #;4> foo foo And it will be namespaced with the module if it is defined in a module. But beware, we might change the representation of record types to be objects instead of symbols at some point so we can add introspection to records. Cheers, Peter signature.asc Description: PGP signature ___ Chicken-users mailing list Chicken-users@nongnu.org https://lists.nongnu.org/mailman/listinfo/chicken-users
[Chicken-users] retrieving a structure's symbol name
Ciao, I know that it is dirty, but is it possible to retrieve the symbol name of a structure from the block object? If I create a structure with: (define (make-it) (##sys#make-structure 'spiffy)) (define O (make-it)) can I extract "spiffy" from the structure object bound to "O"? I searched "library.scm" in CHICKEN's 5.1.0 source without success. TIA -- Marco Maggi ___ Chicken-users mailing list Chicken-users@nongnu.org https://lists.nongnu.org/mailman/listinfo/chicken-users
