KrakenDev/PrediKit

Builder needs method for querying object properties

djbe opened this issue · 14 comments

djbe commented

Case where we want to query an object with related objects, such as:

class Captain: NSObject {
    var name: String
}
class Ship: NSObject {
    var captain: Captain
}
NSPredicate(format: "captain == %@", someCaptain)
NSPredicate(format: "captain.name == 'Chief Supreme'")

There currently is no method to match an object property (example 1), or to match a related object's property (example 2).

Are there currently any plans for this?

hectormatos2011 commented

I completely forgot about this! I'll put one in tonight for you

hectormatos2011 commented

Any opinions on syntax? At the moment you can achieve this by dropping down into strings as well. includeIf.string("captain.name").isEqualTo("Chief Supreme")

hectormatos2011 commented

At the moment I'm thinking something along the lines of this:

NSPredicate(Ship.self) { includeIf in
    includeIf.memberObject(Captain.self).string("name").isEqualTo("Chief Supreme")
}
dariopellegrini commented

I think you’re sending messages to the wrong person.

Dario Pellegrini

http://www.dariopellegrini.com

Il giorno 27 mag 2016, alle ore 04:28, Hector Matos notifications@github.com ha scritto:

@djbe https://github.com/djbe
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hectormatos2011 commented

Oops! Sorry but the username for the OP is @djbe. Is that yours as well?

hectormatos2011 commented

GitHub is showing David Jennes for that username

dariopellegrini commented

I think it’s because I’ve set as favorite this library. Sorry, I didn’t remember that. However that’s not my username

Dario Pellegrini

http://www.dariopellegrini.com

Il giorno 27 mag 2016, alle ore 14:24, Hector Matos notifications@github.com ha scritto:

GitHub is showing David Jennes for that username

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djbe commented

@dariopellegrini He was actually mentioning me, not you :-)

@hectormatos2011 Your syntax suggestion looks great, although I'd make a small change. I wouldn't work with the class type for properties, the property might have a different name (such as "captain1" or "reserveCaptain"). It might be better to just use strings for property names (until we get #selector syntax for getters):

includeIf.memberObject("captain").string("name").isEqualTo("Chief Supreme")
-->
NSPredicate(format: "captain.name == 'Chief Supreme'")

How would you handle the first predicate? You'd still need a call to test object equality, regardless of basic types. Something along the lines of:

includeIf.object("captain").isEqualTo(someCaptain)
-->
NSPredicate(format: "captain == %@", someCaptain)
hectormatos2011 commented

I think I have an idea for it. I'll submit a PR and how would feel about reviewing it?

hectormatos2011 commented

Alright so I just pushed a new version. It should now be available in PrediKit 2.0.3.

djbe commented

@hectormatos2011 Looks great!
I'll try to integrate PrediKit in one of our more complex apps and see if I hit any issues.

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hectormatos2011 commented

Sounds great! Feel free to continue creating issues! And let me know how it goes!

  • 👍1