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April 25, 2015 std.json questions | ||||
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Hello, D community! I'm pretty new to D and to compiled languages in general, and have primarily web background (PHP, JS), when JSON workflow is very organic. I was always sure that JSON is a simple thing, but std.json proves me wrong. So may I have a little advice from more experienced D folk? Say, I have a simple JSON file: { "entities" : [ { "x" : 0, "y" : 0, "texture" : "box1" }, { "x" : 100, "y" : 200, "texture" : "box2", "isControllable" : true } ] } First issue: what is the proper ("idiomatic") way to conver JSONValue to the proper types? Second: what is the proper way of handling boolean values in JSON (how to convert JSON_TYPE.TRUE and JSON_TYPE.FALSE to bool)? Righ now I'm doing is something like this: string data = readText("file.json"); JSONValue[string] parsedData = parseJSON(data).object; JSONValue[] etities = stateData["entities"].array; foreach(e; entities) { int x = to!int(e["x"].integer); int y = to!int(e["y"].integer); string texture = stripExtension(e["texture"].str); auto isControllable = "isControllable" in e; if (isControllable !is null) { if (e["isControllable"].type == JSON_TYPE.TRUE) { isControllable = true; } else { isControllable = false; } } } I think this is ugly and clunky approach, what is the beautiful one? A brief look at code.dlang.org gives us 7 (!) additional JSON libraries. Keeping in mind that D community isn't so huge, I think I'm not the only person struggling with std.json. Are there any plans on upgrading it? Thank you in advance! |
April 25, 2015 Re: std.json questions | ||||
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Posted in reply to tired_eyes | "tired_eyes" <pastuhov85@gmail.com> writes: > > First issue: what is the proper ("idiomatic") way to conver JSONValue > to the proper types? > > Second: what is the proper way of handling boolean values in JSON (how to convert JSON_TYPE.TRUE and JSON_TYPE.FALSE to bool)? > > Righ now I'm doing is something like this: > > string data = readText("file.json"); > JSONValue[string] parsedData = parseJSON(data).object; > JSONValue[] etities = stateData["entities"].array; > > foreach(e; entities) { > int x = to!int(e["x"].integer); > int y = to!int(e["y"].integer); > string texture = stripExtension(e["texture"].str); > > auto isControllable = "isControllable" in e; > > if (isControllable !is null) { > if (e["isControllable"].type == JSON_TYPE.TRUE) { > isControllable = true; > } else { > isControllable = false; > } > } > } > > I think this is ugly and clunky approach, what is the beautiful one? > > A brief look at code.dlang.org gives us 7 (!) additional JSON libraries. Keeping in mind that D community isn't so huge, I think I'm not the only person struggling with std.json. Are there any plans on upgrading it? Hi and welcome to D land. I see discussions on how std.json needs to be upgraded. And it is not well documented. I tried to progressively simplify the code that was posted to show what can be done, but keeping the same spirit. Not necessarily beautiful, but less verbose code. I did not see a simpler way to deal with bools in the std.json code. Others here are experts on idiomatic D, they may show something much better. // First , make it work and show all types void f1() { string data = readText("file.json"); JSONValue parsedData = parseJSON(data); JSONValue entities = parsedData["entities"]; foreach(size_t index, e; entities) { long x = e["x"].integer; long y = e["y"].integer; string texture = stripExtension(e["texture"].str); bool isControllable = false; if ("isControllable" in e) { if (e["isControllable"].type == JSON_TYPE.TRUE) { isControllable = true; } else { isControllable = false; } } writefln("x %d y %d texture %s isControllable %s", x, y, texture, isControllable); } } // Next, let compiler figure types for us void f2() { auto data = readText("file.json"); auto parsedData = parseJSON(data); auto entities = parsedData["entities"]; foreach(size_t _, e; entities) { auto x = e["x"].integer; auto y = e["y"].integer; auto texture = stripExtension(e["texture"].str); bool isControllable = false; if ("isControllable" in e) { isControllable = e["isControllable"].type == JSON_TYPE.TRUE; } writefln("x %d y %d texture %s isControllable %s", x, y, texture, isControllable); } } // A little simpler isControllable. void f3() { auto parsedData = readText("file.json").parseJSON; foreach(size_t _, e; parsedData["entities"]) { auto x = e["x"].integer; auto y = e["y"].integer; auto texture = stripExtension(e["texture"].str); auto isControllable = "isControllable" in e && e["isControllable"].type == JSON_TYPE.TRUE; writefln("x %d y %d texture %s isControllable %s", x, y, texture, isControllable); } } |
April 25, 2015 Re: std.json questions | ||||
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Posted in reply to tired_eyes | On Saturday, 25 April 2015 at 09:56:25 UTC, tired_eyes wrote: > A brief look at code.dlang.org gives us 7 (!) additional JSON libraries. Keeping in mind that D community isn't so huge, I think I'm not the only person struggling with std.json. Are there any plans on upgrading it? See http://wiki.dlang.org/Review_Queue. std.data.json is the proposed replacement for the current phobos json implementation. There is also supposedly std.serialization in the works. |
April 25, 2015 Re: std.json questions | ||||
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Posted in reply to tired_eyes | On Saturday, 25 April 2015 at 09:56:25 UTC, tired_eyes wrote: > I think this is ugly and clunky approach, what is the beautiful one? What you clearly need is a serializer: look at these: http://wiki.dlang.org/Libraries_and_Frameworks#Serialization and also: https://github.com/search?utf8=✓&q=serializer+language%3AD&type=Repositories&ref=searchresults some of them might have an API to save load an object or a struct in a single call. |
April 26, 2015 Re: std.json questions | ||||
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Posted in reply to Baz | Thank everybody for you help. For now, yajl-d seems to be an optimal for my task, however will keep an eye for stdx.data.json too. |
April 26, 2015 Re: std.json questions | ||||
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Posted in reply to Baz | On Saturday, 25 April 2015 at 18:30:33 UTC, Baz wrote:
> On Saturday, 25 April 2015 at 09:56:25 UTC, tired_eyes wrote:
>> I think this is ugly and clunky approach, what is the beautiful one?
>
> What you clearly need is a serializer:
>
> look at these:
>
> http://wiki.dlang.org/Libraries_and_Frameworks#Serialization
>
> and also:
>
> https://github.com/search?utf8=✓&q=serializer+language%3AD&type=Repositories&ref=searchresults
>
> some of them might have an API to save load an object or a struct in a single call.
too bad D:YAML links are broken, do you know where to find that project ?
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April 26, 2015 Re: std.json questions | ||||
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Posted in reply to extrawurst | On Sunday, 26 April 2015 at 17:14:22 UTC, extrawurst wrote: > On Saturday, 25 April 2015 at 18:30:33 UTC, Baz wrote: >> On Saturday, 25 April 2015 at 09:56:25 UTC, tired_eyes wrote: >>> I think this is ugly and clunky approach, what is the beautiful one? >> >> What you clearly need is a serializer: >> >> look at these: >> >> http://wiki.dlang.org/Libraries_and_Frameworks#Serialization >> >> and also: >> >> https://github.com/search?utf8=✓&q=serializer+language%3AD&type=Repositories&ref=searchresults >> >> some of them might have an API to save load an object or a struct in a single call. > > too bad D:YAML links are broken, do you know where to find that project ? https://github.com/kiith-sa/D-YAML |
April 27, 2015 Re: std.json questions | ||||
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Posted in reply to Baz | On Saturday, 25 April 2015 at 18:30:33 UTC, Baz wrote: > On Saturday, 25 April 2015 at 09:56:25 UTC, tired_eyes wrote: >> I think this is ugly and clunky approach, what is the beautiful one? > > What you clearly need is a serializer: > > look at these: > > http://wiki.dlang.org/Libraries_and_Frameworks#Serialization > > and also: > > https://github.com/search?utf8=✓&q=serializer+language%3AD&type=Repositories&ref=searchresults > > some of them might have an API to save load an object or a struct in a single call. Also http://code.dlang.org/search?q=json |
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