October 6th, 2008
Numbers in Ioke
One of my guiding principles for Ioke is that I want to try to at least think through most of the parts of it, including things that most other languages have/don’t have. One of the decisions I made quite far back but haven’t written about concerns numbers. I have decided to go back to PL/I and COBOL with regards to real numbers. Well, that’s not the whole truth. I’m simply not going to have a representation of for real numbers in Ioke. Instead something like “101.1” will result in a decimal number. They will have infinite range in Ioke, and they will always be exact. To me it’s never made sense to have float and double in a general purpose programming language. Or, it makes sense from a performance perspective, but most of the time these types just bite us in the behind.
How many times have you seen numbers represented as float or double in C, C++, Java, C# or any of the other languages that include floating points? If you want to do scientific computation or non-discrete math, Ioke is probably not the right language anyway. But since it runs on top of the JVM you can write that part of your application in Java…
So, to recap, the type (which I might call ‘Decimal’ or ‘Radix’) will be exact. It will have potentially infinite range both in the magnitude and the fraction. Ioke will not have NaN or +/-Inf.
Also going back to other languages (such as Scheme and Smalltalk), Ioke will have a numerical tower. That means things like rationals will be in the language. So will integers of course (and yes, they will also have infinite range). I’m still thinking about complex numbers. They might be there, but falling back on my reasoning for not having floats in the language, having complex numbers seem kinda inconsistent. So probably not. I will have magnitudes, units and quantities, since these are extremely useful features in a language. That means money will be a combination of a ‘Decimal’ and a Currency Unit. There might be support for syntax here, in the style of Kawa Scheme (a quantity is a number directly followed by a unit name, without any whitespace: 100.2dollar, 5kg, etc. Obviously, there will be expanded ways of calling these, such as: Units Currency dollar(100.2), Units Mass kg(5). I haven’t decided on the exact hierarchy or syntax right now, but I know I will not build it from scratch. Instead I’m going to use gnu.math from Kawa.
So that’s my thinking about numbers for Ioke. The other details will be mostly natural things. I haven’t decided which bases should be literals, or if I can do something like Common Lisp with this. We’ll see. (And in fact, I haven’t even added numbers to the parser yet… They haven’t been necessary.)
