• GrimMaple (10/10) Nov 06 2019 Hello everyone! I'm fairly new to D and don't know much about its
• Jonathan Marler (18/28) Nov 06 2019 Looking at the json spec, it looks like it doesn't distinguish
• GrimMaple (7/26) Nov 07 2019 Thank you for your input! The idea with additional function is

GrimMaple <grimmaple95 gmail.com> writes:

Hello everyone! I'm fairly new to D and don't know much about its 
internals, but I've been playing around with std.json and found 
out a pretty weird behaviour in it. Let's say I have a JSON like 
this: { "Value": 123 }. When I parse it and try to 
writeln(json["Value"].floating) it throws a runtime error saying 
that "Value" is not "floating". I understand that it's being 
taken as an integer, but aren't integers subset of decimals? I 
would expect it to be able to convert to float no problem, but 
it's not the case. Does anyone know if this behaviour is intended 
or if it's a bug?

Jonathan Marler <johnnymarler gmail.com> writes:

On Wednesday, 6 November 2019 at 21:48:48 UTC, GrimMaple wrote:
 Hello everyone! I'm fairly new to D and don't know much about 
 its internals, but I've been playing around with std.json and 
 found out a pretty weird behaviour in it. Let's say I have a 
 JSON like this: { "Value": 123 }. When I parse it and try to 
 writeln(json["Value"].floating) it throws a runtime error 
 saying that "Value" is not "floating". I understand that it's 
 being taken as an integer, but aren't integers subset of 
 decimals? I would expect it to be able to convert to float no 
 problem, but it's not the case. Does anyone know if this 
 behaviour is intended or if it's a bug?

Looking at the json spec, it looks like it doesn't distinguish 
between integers and floating point values.

As D is a native language, the distinction between integer and 
floating point values it semantically important.  The operations 
on each have very different behavior.

That being said, adding support in `std.json` to interpret both 
integers and floating points as floats should be trivial to 
implement.  Or you could add your own function in your app.

float asFloating(JSONValue value)
{
     return (value.type == JSONType.integer) ?
         cast(float)value.integer : value.floating;
}

auto json = parseJSON(`{"num":123}`);
writefln("num is: %s", json["num"].asFloating);
json = parseJSON(`{"num":123.456}`);
writefln("num is: %s", json["num"].asFloating);

GrimMaple <grimmaple95 gmail.com> writes:

On Wednesday, 6 November 2019 at 23:14:45 UTC, Jonathan Marler 
wrote:
 On Wednesday, 6 November 2019 at 21:48:48 UTC, GrimMaple wrote:
 [...]

 Looking at the json spec, it looks like it doesn't distinguish 
 between integers and floating point values.

 As D is a native language, the distinction between integer and 
 floating point values it semantically important.  The 
 operations on each have very different behavior.

 That being said, adding support in `std.json` to interpret both 
 integers and floating points as floats should be trivial to 
 implement.  Or you could add your own function in your app.

 float asFloating(JSONValue value)
 {
     return (value.type == JSONType.integer) ?
         cast(float)value.integer : value.floating;
 }

 auto json = parseJSON(`{"num":123}`);
 writefln("num is: %s", json["num"].asFloating);
 json = parseJSON(`{"num":123.456}`);
 writefln("num is: %s", json["num"].asFloating);

Thank you for your input! The idea with additional function is 
great, I always forget D can do that. As to adding this to 
`std.json`, I'm both hands down to doing it myself, just unsure 
if I should submit a bug first or if I can just PR it straight 
away.