Smalltalk Zero
stz
Since I'm trying to write example code I have found it annoying that I don't have syntax highlighting. My editor of choice these days is zed which uses tree-sitter as its parser. I suppose I could take everything we know and try to make a parser
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One of the cool features of the maybe pattern is how some values have a 'not instantiated' state by default - such as pointers. A memory-address of 0 can mean 'there is no pointer' while any other value means there is a pointer. The default maybe
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A controversial topic in the programming world - how do you end a statement? In Smalltalk you do it with a fullstop . In C you do it with a ; In Javascript you do it with a ; unless you don't because sometimes it knows what you mean. In Python
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Now that we have traits, interfaces, generics, poly types ... we'll just call them traits until I realise that's the wrong word ... we can move on to the burning question in my mind. How the heck do we implement array? array = (address: memory-address, length: uint,) Great! That
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I posed the question - if we have the ability to do traits then should we not favour it over inheritance? The answer is about simplicity of understanding the code and also writing it. Freedom of expression is great but freedom from other peoples excessive expression also has its merits.
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Before we can write an interpreter or compiler we need to be able to parse the syntax of stz. The rules are fairly simple so far. There's a few characters that are special: start-bracket ( stop-bracket ) start-block [ stop-block ] start-make { stop-make } divider | return ^ string-quote ' " ` reference & keyword-break : comment-start
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Writing out enumerated values should be as simple as listing them. For instance: north = 1 east = 2 south = 3 west = 4 The whole point of enums though is to scope them away inside a namespace. To use the enum as a type. The problem with throwing random names out there
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When we reviewed the syntax so far we ran in to a problem with arrays and maps. We don't have syntax for them. What we have so far is the ability to make an object on the stack: { the-class | messages to send to the class... } If we stick
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Writing a whole compiler from scratch is a lot of work. There's so many parts to it from SSA to instruction fitting to register allocation optimisation and constant folding and and and... I don't really want to do all that. The simplest solution is to transpile
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Something that can save a great deal of headaches in programming is defer. file-handle = io open: 'foo.txt' mode: io O_RDONLY defer io close: file-handle In Smalltalk, with garbage collection, we can be told by the garbage collector that something is being destroyed. Things like IO will
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making an object: { expression | expression list sent to the new instance } making a class: my-class = class: { list of variable: expression list } making an enum (* note #1): my-enum = enum: { list of names } array of things (last , is optional): a, b, c, empty array () making a union of classes: first-class + second-class making
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In a previous post I wrote this piece of code: [ list add: element | &(list-of: (class-of: element), (class-of: element) | capacity == length then: [ grow ] elements[length] = element length += 1 ] The signature has three sections: 1. the pattern that will be used when calling this method 2. the types that must match