Chaos in a Can

As great as Mathieu Jacques's MTParser is, it only supports double-precision floating point numbers and it only works with .NET through a COM interface, which means I have less control over the parser and I have to register the dll.  Therefore, GlassCalc 2 will feature a new parser which I am writing from the ground up. I call this new parser GCParser. I am awesome at naming things.

Here is a fairly technical description of how GCParser will work:

Design Goals of GCParser

• The parser will operate on objects deriving from GCObject. This is a completely generic class, and in fact, the only function a GCObject must have converts the object to a string so it can be displayed.
• GCParser will have two types of GCObject out-of-the-metaphorical-box: numbers and arrays. Arrays are lists of GCObjects. This means GCParser will support vector operations, and since you can make arrays of arrays, probably matrix operations too.
• The syntax for arrays should be familiar to anyone who has programmed in C or JavaScript. a = [1, 2, 3] is a 3-element array. a[0] retrieves the first element of the array.
• GCObjects can have properties and functions. For instance, arrays will have x, y, and z properties to make 3d vector operations easy. [1, 2, 3].x will return 1. Also, [2, 3, 1].sort() would return [1, 2, 3].
• GCParser will be able to operate on multiple types at once. For instance, when executing 2 * [3, 4] the parser would search for a Multiply function taking two arguments of types GCNumber and GCArray. This expression would evaluate to [6, 8]. If no function was found, the parser would throw a type error.
• GCParser will be extensible. Extensions will be able to define not only constants and functions, but new GCObject types as well. For instance, a complex numbers extension could define a GCComplexNumber class, functions for operating on complex numbers, and a constant i. Since the parser will only create numbers and arrays normally, the extension would also need to define a constructor function, Complex(real, imag), to make complex numbers. If the extension defined functions for adding/multiplying numbers and complex numbers together, the expression 1 + 2i would also work. The parser would interpret this as (number: 1) + ((number: 2) * (complex: 0 + i)).
• I haven't figured out how this would work yet, but I want GCParser to support expressions like [1, 2, 3].sort((a,b) => b<a). This would send a predicate function to the sort function telling it how to sort—in this case, sort descending. Likewise, Sum(n => 0.5^n, 1, 50) would sum 0.5ⁿ from n = 1 to 50.
• Parsing occurs in three stages: tokenization, parsing and evaluation. Tokenization takes the expression and figures out what all the individual parts mean. It also generates a structure which the syntax highlighter can use instead of the convoluted regular expression system GlassCalc currently uses. Parsing takes the tokenized expression and converts it into a binary tree of operations. Evaluation traverses the tree, running each operation until it gets a final result. Parsing and evaluation will not run on the UI thread, so the program won't freeze up if you run a long calculation.

Things That Are Not Design Goals of GCParser

• Be really fast.

tl;dr Version

• GlassCalc 2 will have a new parser. It will be magic, rainbows and unicorns. It will calculate just about anything.
• If it can't calculate something, you can probably write an extension so it can.

So, when will it be done? Eventually. I have the tokenizer mostly complete. I am waiting for .NET 4.5 to be released before I start work on the UI, as I will make use of its new asynchronous stuff.

It has been far too long since I last updated GlassCalc. There's a new version with some bug fixes. Check the GlassCalc page for download links.

This update fixes some bugs caused by GlassCalc applying exponential formatting to hexadecimal numbers containing "e". It also fixes a formatting bug where a thousands separator would appear next to a negative sign (ex: -100 was displayed as - 100) and a syntax highlighting bug where a variable ending with the name of a constant would be highlighted partially as a variable and partially as a constant.

Also, here's a status update on GlassCalc 2: I've decided that MTParser isn't capable of all the things I would like to do with GlassCalc, and none of the free parser libraries I've encountered are either, so I am now writing my own parser (MTParser is excellent, but its existence as a COM component makes installing GlassCalc a pain and it doesn't support lists or higher precision math). The primary goals of the new parser are:

• Support all of the GlassCalc's current syntax without tons of regex magic.
• Allow for basing syntax highlighting off of the parsed expression instead of using even more regex magic.
• Add support for lists (what you math people might call n-dimensional vectors) and possibly lists of lists (which could be used to perform matrix math).
• Possibly add support for high-precision math.

So far, I have a system that tokenizes an expression character-by-character as you type it—that is, it splits the expression up into numbers, operators, symbols, and so on. The cool thing about doing this character-by-character is that by the time you hit Enter to evaluate, part of the parsing work is already done. In fact, I can use this already-finished part to speed up syntax highlighting and to show you the result of simple calculations before you even hit enter without reparsing every time you add a character. Of course, if you start messing with the middle of your expression, I have to reparse everything.

I am also experimenting with different GUI designs. I may post some mock-ups here later to see what you think.

Also, once I have made a little more progress, I'm going to put GlassCalc 2 up on Github. That's right, GlassCalc 2 is going to be open source. The only thing keeping me from open-sourcing GlassCalc was figuring out what MTParser's license would and wouldn't let me do with regards to distributing MTParser's source/binaries. Now that I'm not using MTParser, there aren't any problems with going open source.