Overwrite equals in defrecord

[Marc Dzaebel]

(defrecord R [x y]) automatically defines a reasonable equals method using x & y. However, is it possible to overwrite the method as it should use X only? My tries resulted in "Duplicate method name&signature in class ...". Do I have to use extend-type?

[Marc Dzaebel]

http://cmayes.wikispaces.com/PracticalClojure13: ...

defrecord does not support Java class inheritance, so it cannot override methods of Java classes, even abstract classes. However, it does permit you to override methods of java.lang.Object such as hashCode, equals, and toString. Simply include java.lang.Object in the defrecord as if it were an interface. Clojure will generate good value-based implementations of the hashCode and equals methods, so it is rarely necessary to implement them yourself.

(defrecord R [x y] java.lang.Object (equals [_ r](= x(.x r))))
--> Duplicate method name&signature in class file

[Jim - FooBar();]

use deftype which is more low-level and I think doesn't define equals or put y in meta data that don't participate in equality...:)

Jim

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[Marc Dzaebel]

>> use deftype which is more low-level and I think doesn't define equals or put y in meta data that don't participate in equality...:)

Hi Jim,

this works! However, if you need the multiple features of records, you would need to have the generated code of defrecord in order to reimplement records with deftype. Is there something available?

Thanks, Marc

[Andrii V. Mishkovskyi]

On Fri, Oct 25, 2013 at 4:41 PM, Marc Dzaebel <mdza...@web.de> wrote:

However, if you need the multiple features of records, you would need to have the generated code of defrecord in order to reimplement records with deftype. Is there something available?

Hey Marc,

I've recently been using this little library potemkin which has a few useful deftype-like macros that would save a lot of typing (albeit I had a different use case from yours), maybe deftype+ will work for you: https://github.com/ztellman/potemkin#def-abstract-type-and-deftype

Cheers.

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Wbr, Andrii V. Mishkovskyi.

He's got a heart of a little child, and he keeps it in a jar on his desk.