Re: Typedef-like functionality for Clojure records?
Thanks for the suggestion. I'll take a look at prismatic/schema. On Thu, Sep 26, 2013 at 5:21 PM, Jason Wolfe ja...@w01fe.com wrote: I'm not sure if this would meet your need (it doesn't help with your proximate defrecord issue), but if you're primarily interested in documentation and validation you could consider prismatic/schema [1] as a translation target, and just represent your data with maps. [1] https://github.com/Prismatic/schema On Wednesday, September 25, 2013 10:47:35 PM UTC-7, Vincent Chen wrote: Hi, I have in my hands an XML description of data structures that I want to mechanically translate into Clojure. There are struct and typedef elements, with struct being similar to structs in C (list of fields) and typedef being similar to typedef in C (defining new name for already defined structs). I model structs using Clojure records, but I'm not sure how to refer to them with a new name when it comes to typedefs. Given the following specification: struct name=foo field name=a/ field name=b/ /struct typedef oldname=foo newname=bar I would create records: (defrecord foo [a b]) (defrecord bar [a b]) The problem is that struct foo and typedef bar lives in different namespaces, i.e. I don't have foo's specification when I encounter typedef bar. What I'd like to do is (def bar some-ns/foo), but what about -foo and map-foo? So should I: - (def bar some-ns/foo) (def -bar some-ns/-foo) (def map-bar some-ns/map-foo), while hoping that Clojure doesn't extend records syntax/capabilities in the future? - Use something else than records to model structs (suggestions welcome)? - Other? Thanks, Vincent -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out. -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: Typedef-like functionality for Clojure records?
On Thu, Sep 26, 2013 at 1:49 AM, Marshall Bockrath-Vandegrift
llas...@gmail.com wrote:
Vincent Chen noodle...@gmail.com writes:
- Use something else than records to model structs (suggestions welcome)?
Maps.
Records have concrete Java types, which allows them to implement
interfaces and participate in protocols. Fields defined on a record
type are backed by JVM object fields, which can increase performance.
But there are no strictness benefits – a record may have any number of
additional keys associated to values:
(defrecord Foo [bar])
;;= user.Foo
(map-Foo {:bar 1, :baz 2})
;;= #user.Foo{:bar 1, :baz 2}
(class (map-Foo {:bar 1, :baz 2}))
;;= user.Foo
So my suggestion would be to instead turn your `struct` definitions into
functions validating that the expected fields are present within plain
maps. (Assuming some sort of strictness/validation is the goal.)
Thanks for the suggestions.
My records (structs) do actually implement protocols, since the
structs represent something which has to be sent over the wire.
Clojure being a dynamic language means that I have to specify the
types of each field of a struct, and I do it as part of a protocol
implemented by the records.
If I'm getting you correctly, you're suggesting that instead of
(defrecord Foo [a b c])
I should rather have
(defn make-foo [a b c]
{:a a, :b b, :c c})
? That could work, even though I had tried to avoid having to do this
when I started. I guess rather than protocols I'll just use
multimethods instead.
Thanks for your help,
Vincent
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Re: Typedef-like functionality for Clojure records?
I'm not sure about your actual questions, but you should note that `foo` is
not actually a var which you can reference like `some-ns/foo`. Rather, it
is a Class. Consider:
user= (defrecord Thing [a b])
user.Thing
user=
user= (def OtherThing Thing)
#'user/OtherThing
user=
user= (Thing. hello sir)
#user.Thing{:a hello, :b sir}
user=
user= (OtherThing. hello sir)
CompilerException java.lang.IllegalArgumentException: Unable to resolve
classname: OtherThing,
compiling:(/private/var/folders/rz/2h_qlr5d2m7dts2xpshlz_nr000c_x/T/form-init123235568201547659.clj:1:1)
So you might be wise to put another layer of abstraction in there if you
need to alias the class in addition to it's constructor functions.
On Thursday, 26 September 2013 06:47:35 UTC+1, Vincent Chen wrote:
Hi,
I have in my hands an XML description of data structures that I want
to mechanically translate into Clojure. There are struct and
typedef elements, with struct being similar to structs in C (list
of fields) and typedef being similar to typedef in C (defining new
name for already defined structs).
I model structs using Clojure records, but I'm not sure how to refer
to them with a new name when it comes to typedefs. Given the
following specification:
struct name=foo
field name=a/
field name=b/
/struct
typedef oldname=foo newname=bar
I would create records:
(defrecord foo [a b])
(defrecord bar [a b])
The problem is that struct foo and typedef bar lives in different
namespaces, i.e. I don't have foo's specification when I encounter
typedef bar. What I'd like to do is (def bar some-ns/foo), but what
about -foo and map-foo?
So should I:
- (def bar some-ns/foo) (def -bar some-ns/-foo) (def map-bar
some-ns/map-foo), while hoping that Clojure doesn't extend records
syntax/capabilities in the future?
- Use something else than records to model structs (suggestions welcome)?
- Other?
Thanks,
Vincent
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Re: Typedef-like functionality for Clojure records?
Vincent Chen noodle...@gmail.com writes:
- Use something else than records to model structs (suggestions welcome)?
Maps.
Records have concrete Java types, which allows them to implement
interfaces and participate in protocols. Fields defined on a record
type are backed by JVM object fields, which can increase performance.
But there are no strictness benefits – a record may have any number of
additional keys associated to values:
(defrecord Foo [bar])
;;= user.Foo
(map-Foo {:bar 1, :baz 2})
;;= #user.Foo{:bar 1, :baz 2}
(class (map-Foo {:bar 1, :baz 2}))
;;= user.Foo
So my suggestion would be to instead turn your `struct` definitions into
functions validating that the expected fields are present within plain
maps. (Assuming some sort of strictness/validation is the goal.)
-Marshall
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Re: Typedef-like functionality for Clojure records?
I'm not sure if this would meet your need (it doesn't help with your proximate defrecord issue), but if you're primarily interested in documentation and validation you could consider prismatic/schema [1] as a translation target, and just represent your data with maps. [1] https://github.com/Prismatic/schema On Wednesday, September 25, 2013 10:47:35 PM UTC-7, Vincent Chen wrote: Hi, I have in my hands an XML description of data structures that I want to mechanically translate into Clojure. There are struct and typedef elements, with struct being similar to structs in C (list of fields) and typedef being similar to typedef in C (defining new name for already defined structs). I model structs using Clojure records, but I'm not sure how to refer to them with a new name when it comes to typedefs. Given the following specification: struct name=foo field name=a/ field name=b/ /struct typedef oldname=foo newname=bar I would create records: (defrecord foo [a b]) (defrecord bar [a b]) The problem is that struct foo and typedef bar lives in different namespaces, i.e. I don't have foo's specification when I encounter typedef bar. What I'd like to do is (def bar some-ns/foo), but what about -foo and map-foo? So should I: - (def bar some-ns/foo) (def -bar some-ns/-foo) (def map-bar some-ns/map-foo), while hoping that Clojure doesn't extend records syntax/capabilities in the future? - Use something else than records to model structs (suggestions welcome)? - Other? Thanks, Vincent -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Typedef-like functionality for Clojure records?
Hi, I have in my hands an XML description of data structures that I want to mechanically translate into Clojure. There are struct and typedef elements, with struct being similar to structs in C (list of fields) and typedef being similar to typedef in C (defining new name for already defined structs). I model structs using Clojure records, but I'm not sure how to refer to them with a new name when it comes to typedefs. Given the following specification: struct name=foo field name=a/ field name=b/ /struct typedef oldname=foo newname=bar I would create records: (defrecord foo [a b]) (defrecord bar [a b]) The problem is that struct foo and typedef bar lives in different namespaces, i.e. I don't have foo's specification when I encounter typedef bar. What I'd like to do is (def bar some-ns/foo), but what about -foo and map-foo? So should I: - (def bar some-ns/foo) (def -bar some-ns/-foo) (def map-bar some-ns/map-foo), while hoping that Clojure doesn't extend records syntax/capabilities in the future? - Use something else than records to model structs (suggestions welcome)? - Other? Thanks, Vincent -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
