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wrapping up haku

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liquidex 2024-07-30 23:24:14 +02:00
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commit 1de5234215
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10
content/programming.tree
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@ -7,9 +7,9 @@
% id = "01HPD4XQQ5GPQ20C6BPA8G670F"
- ### :folder: blog
% content.link = "programming/blog/tairu"
id = "01HPD4XQQ5WM0APCAX014HM43V"
+ :page: [featured]{.badge .blue} tairu - an interactive exploration of 2D autotiling techniques
% content.link = "programming/blog/haku"
id = "01J4J4PAXRWZDP9PAZNGCQ9S3D"
+ [featured]{.badge .blue} :page: haku - writing a little programming language for fun
% content.link = "programming/blog/lvalues"
id = "01HY5R1ZW0M0Y5KQ1E8F0Q73ZT"
@ -23,6 +23,10 @@
id = "01HTWN4XB2YMF3615BE8V6Y76A"
+ :page: OR-types
% content.link = "programming/blog/tairu"
id = "01HPD4XQQ5WM0APCAX014HM43V"
+ :page: tairu - an interactive exploration of 2D autotiling techniques
% id = "programming/projects"
content.link = "programming/projects"
+ ### :folder: projects

351
content/programming/blog/haku.tree
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@ -2088,7 +2088,7 @@ scripts = ["treehouse/vendor/codejar.js", "treehouse/components/literate-program
console.log(result);
}
} catch (error) {
console.log(error.stack ? error.toString() + "\n\n" + error.stack : error.toString());
console.log(error.toString());
}
}
@ -2238,6 +2238,355 @@ scripts = ["treehouse/vendor/codejar.js", "treehouse/components/literate-program
% id = "01J42RD8Y4ED5TTP392VYGGWXS"
- I'll carry on with them for a bit longer though, I really don't wanna write a complicated parser right now.
% id = "01J4J4ERA0M54GAJQ02K43ZWKJ"
- ### string manipulation
% id = "01J4J4ERA06GESAKGFQ7S44K9W"
- being able to calculate numbers is good, but remember how we can only output one number - that kinda sucks!
% id = "01J4J4ERA09RQ9YJ0WQKRER0AP"
- therefore I'd like to be able to work on _strings_ in haku.
that way we'll be able to implement more interesting programs, including my personal favorite - the Mandelbrot set!
% id = "01J4J4ERA09QCEF4CAKBH0GPTK"
- to start things off, we'll implement a basic syntax for strings.
technically speaking we don't really _need_ string syntax, but it's gonna make our code examples a lot nicer if we have it!
% id = "01J4J4ERA0FKDMMRAY6QH6TJJN"
- I find the modern orthodox string syntax just fine: `"text between quotation marks."`
% id = "01J4J4ERA0H13X1GD0HX0YPCM2"
- we'll only support _double_ quotation marks to keep the syntax lean.
% id = "01J4J4ERA05GR37V8RW0K2PJVN"
- there'll be no escape sequences for the time being - they inflate the surface area of the lexer quite a lot, and aren't needed when you can store a bunch of magic strings in variables:
```haku
(cat ; `cat` will be our string concatenation function
"Hello, world!" \n ; notice how \n is just a regular variable!
"This is another line.")
```
% id = "01J4J4ERA0VKJEBRT4N6YQ1VQ0"
- stealing the idea from Zig, I'm making strings single-line _only_.
if you want a multiline string, look at the example above.
% id = "01J4J4ERA0FTYBQ36KDCG0D7Z2"
- let's add that to the lexer then!
{:program=haku}
```javascript
lexer.string = (state) => {
lexer.advance(state); // skip over initial quotation mark
while (lexer.current(state) != '"') {
if (lexer.current(state) == eof) {
return "error";
}
lexer.advance(state);
}
lexer.advance(state); // skip over closing quotation mark
return "string";
};
lexer.nextToken = (state) => {
let c = lexer.current(state);
if (c == '"') {
return lexer.string(state); // <--
}
if (isDigit(c)) {
lexer.advanceWhile(state, isDigit);
return "integer";
}
if (isIdentifier(c)) {
lexer.advanceWhile(state, isIdentifier);
return "identifier";
}
if (c == "(" || c == ")") {
lexer.advance(state);
return c;
}
if (c == eof) return eof;
lexer.advance(state);
return "error";
};
```
% id = "01J4J4ERA0AP38ZS3HCSXAMKBZ"
- and to the parser...
{:program=haku}
```javascript
parser.parseExpr = (state) => {
let token = parser.current(state);
switch (token.kind) {
case "integer":
case "identifier":
case "string": // <--
parser.advance(state);
return { ...token };
case "(":
return parser.parseList(state, token);
default:
parser.advance(state);
return {
kind: "error",
error: "unexpected token",
start: token.start,
end: token.end,
};
}
};
```
% id = "01J4J4ERA0KJWD4ZCKH2J5JSRN"
- now if we use a string, we should get an error from the interpreter about an unknown node kind:
{:program=haku}
```haku
"hello!"
```
{:program=haku}
```output
Error: unhandled node kind: string
```
% id = "01J4J4ERA060262W39D1Q6W1KE"
- so to top this all off, we'll make the interpreter produce a string value for string literals, like it produces numbers for integer literals:
{:program=haku}
```javascript
treewalk.eval = (state, node) => {
switch (node.kind) {
case "integer":
return parseInt(node.source);
case "string": // <--
// NOTE: We chop the quotes off of the string literal here.
return node.source.substring(1, node.source.length - 1);
case "identifier":
return treewalk.lookupVariable(state, node.source);
case "list":
let functionToCall = treewalk.eval(state, node.children[0]);
return functionToCall(state, node);
case "toplevel":
let result = undefined;
for (let i = 0; i < node.children.length; ++i) {
result = treewalk.eval(state, node.children[i]);
if (result !== undefined && i != node.children.length - 1)
throw new Error(`expression ${i + 1} had a result despite not being the last`);
}
return result;
default:
throw new Error(`unhandled node kind: ${node.kind}`);
}
};
```
{:program=haku}
```haku
"hello!"
```
{:program=haku}
```output
hello!
```
% id = "01J4J4ERA0YNVW33GQ7EWYSJHX"
- with strings added to the language, we'll need some basic operations to put together and break apart strings.
% id = "01J4J4ERA0Z20JEXFPYKTSP0SK"
- I don't want to write a whole load of wrapper code every single time we want to declare a simple JavaScript function that's available from haku, so let's build a helper for that first:
{:program=haku}
```javascript
export function wrapJavaScriptFunctionVarargs(func) {
return (state, node) => {
let args = Array(node.children.length - 1);
for (let i = 1; i < node.children.length; ++i) {
args[i - 1] = treewalk.eval(state, node.children[i]);
}
return func(...args);
};
}
export function wrapJavaScriptFunction(func) {
let inner = wrapJavaScriptFunctionVarargs(func);
return (state, node) => {
if (node.children.length != func.length + 1)
throw new Error(
`\`${func.name}\` expects ${func.length} arguments, but ${node.children.length - 1} were given`,
);
return inner(state, node);
};
}
```
% id = "01J4J4ERA0AKYMCN24F46H4AYF"
- with that, we'll start off with `cat`, our concatenation function.
mainly because I really like the name. `=^..^=`
{:program=haku}
```javascript
builtins.cat = wrapJavaScriptFunctionVarargs((...strings) => strings.join(""));
```
{:program=haku}
```haku
(cat "hello, " "world!")
```
{:program=haku}
```output
hello, world!
```
% id = "01J4J4ERA0JTNMGFJCPP1VBJMT"
- then there's also `sub`, for indexing.
one thing that always seemed kind of arbitrary is that `substring` in JavaScript and other languages defaults its argument to the string's length; I personally think if the second argument is not provided, you almost always want to just get the character at that index.
{:program=haku}
```javascript
builtins.sub = wrapJavaScriptFunctionVarargs((str, start, end) => {
if (typeof str != "string") throw new Error("`sub` expects a string as the first argument");
if (typeof start != "number") throw new Error("`sub` expects a number as the second argument");
end ??= start + 1;
return str.substring(start, end);
});
```
{:program=haku}
```haku
(sub "hello, world!" 0)
```
{:program=haku}
```output
h
```
{:program=haku}
```haku
(sub "hello, world!" 0 5)
```
{:program=haku}
```output
hello
```
% id = "01J4J4ERA0MEK62M974XP8390F"
- then of course to be able to look at a suffix of the string, we'll need its `len`.
{:program=haku}
```javascript
builtins.len = wrapJavaScriptFunction((string) => string.length);
```
{:program=haku}
```haku
(len "hello, world!")
```
{:program=haku}
```output
13
```
% id = "01J4J4ERA0EE0J4DFTBMJXXCQ0"
- then we'll also have a pair of functions that will convert between Unicode code points and strings.
{:program=haku}
```javascript
builtins.chr = wrapJavaScriptFunction((n) => String.fromCodePoint(n));
builtins.ord = wrapJavaScriptFunction((s) => s.codePointAt(0));
```
{:program=haku}
```haku
(chr 33)
```
{:program=haku}
```output
!
```
{:program=haku}
```haku
(ord "!")
```
{:program=haku}
```output
33
```
% id = "01J4J4ERA0P3WZNN2TE1XDQKG3"
- and last but not least, a pair of functions to convert between numbers and strings.
{:program=haku}
```javascript
builtins["to-string"] = wrapJavaScriptFunction((n) => n.toString());
builtins["to-number"] = wrapJavaScriptFunction((s) => parseInt(s));
```
{:program=haku}
```haku
(cat "today's magic number is: " (to-string 65))
```
{:program=haku}
```output
today's magic number is: 65
```
{:program=haku}
```haku
(+ (to-number "60") 5)
```
{:program=haku}
```output
65
```
we won't care about the fallibility of `to-number` for now; we're hand-waving away all the error handling anyways.
% id = "01J4J4ERA03H04VT286CPEE5PK"
- ### conclusion for now
% id = "01J4J4ERA0NXEP21DCXDHGD8TG"
- at this point I've experimented and thought about it enough that I now know just the perfect application for such a language, so I'll be wrapping up here.
maybe I'll revisit haku some other time, but for now... it's time to call it done.
% id = "01J4J4PAX4Q820S0YEAXDHRATJ"
- I'll be continuing to develop haku in another project, simply as "haku."
this version will be called "haku 0," the progenitor of the final language.
% id = "01J4J4PAX4JS3Q8K0503ZT0B42"
- {:program=haku}
```haku
; Here's a blank canvas for you to play around with!
(cat "hello" (chr 44) " world!")
```
{:program=haku}
```output
hello, world!
```
% stage = "Draft"
id = "01J3K8A0D1D0NTT3JYYFMRYVSC"
- ### tests

17
content/treehouse/new.tree
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@ -3,12 +3,14 @@
styles = ["new.css"]
feed = "news"
% id = "01HQ6G30PTVT5H0Z04VVRHEZQF"
- [featured]{.badge .blue} ever wondered how Terraria renders its worlds? or how editors like Tiled manage to make painting tiles so easy?
- [featured]{.badge .blue} I was bored over a weekend, so I decided to write the tiniest programming language I could imagine.
it came out looking pretty Lispy, and I'm glad about that!
I learned a ton about Lisps in the process of researching it.
even though it didn't end up having macros...
### tairu - an interactive exploration of 2D autotiling techniques
### haku - writing a little programming language for fun
[read][page:programming/blog/tairu]
[read][page:programming/blog/haku]
% id = "01J293BFEBT15W0Z3XF1HEFGZT"
- sometimes people call me crazy for saying that bashing JavaScript is senseless and that it's not as bad of a language as people make it out to be.
@ -83,3 +85,10 @@ seriously though. I don't like them.
### liquidex's treehouse: design
[read: _on digital textures_][page:design/digital-textures] [go to branch][page:design]
% id = "01HQ6G30PTVT5H0Z04VVRHEZQF"
- ever wondered how Terraria renders its worlds? or how editors like Tiled manage to make painting tiles so easy?
### tairu - an interactive exploration of 2D autotiling techniques
[read][page:programming/blog/tairu]

17
static/js/components/haku/sexp.js
View file

@ -40,12 +40,29 @@ lexer.skipWhitespaceAndComments = (state) => {
}
};
lexer.string = (state) => {
lexer.advance(state); // skip over initial quotation mark
while (lexer.current(state) != '"') {
if (lexer.current(state) == eof) {
return "error";
}
lexer.advance(state);
}
lexer.advance(state); // skip over closing quotation mark
return "string";
};
export const isDigit = (c) => c >= "0" && c <= "9";
export const isIdentifier = (c) => /^[a-zA-Z0-9+~!@$%^&*=<>+?/.,:\\|-]$/.test(c);
lexer.nextToken = (state) => {
let c = lexer.current(state);
if (c == '"') {
return lexer.string(state);
}
if (isDigit(c)) {
lexer.advanceWhile(state, isDigit);
return "integer";

44
static/js/components/haku/treewalk.js
View file

@ -25,6 +25,10 @@ treewalk.eval = (state, node) => {
case "integer":
return parseInt(node.source);
case "string":
// NOTE: We chop the quotes off of the string literal here.
return node.source.substring(1, node.source.length - 1);
case "identifier":
return treewalk.lookupVariable(state, node.source);
@ -158,3 +162,43 @@ builtins.def = (state, node) => {
let value = treewalk.eval(state, node.children[2]);
state.env.set(name.source, value);
};
export function wrapJavaScriptFunctionVarargs(func) {
return (state, node) => {
let args = Array(node.children.length - 1);
for (let i = 1; i < node.children.length; ++i) {
args[i - 1] = treewalk.eval(state, node.children[i]);
}
return func(...args);
};
}
export function wrapJavaScriptFunction(func) {
let inner = wrapJavaScriptFunctionVarargs(func);
return (state, node) => {
if (node.children.length != func.length + 1)
throw new Error(
`\`${func.name}\` expects ${func.length} arguments, but ${node.children.length - 1} were given`,
);
return inner(state, node);
};
}
builtins.cat = wrapJavaScriptFunctionVarargs((...strings) => {
return strings.join("");
});
builtins.sub = wrapJavaScriptFunctionVarargs((str, start, end) => {
if (typeof str != "string") throw new Error("`sub` expects a string as the first argument");
if (typeof start != "number") throw new Error("`sub` expects a number as the second argument");
end ??= start + 1;
return str.substring(start, end);
});
builtins.len = wrapJavaScriptFunction((string) => string.length);
builtins.chr = wrapJavaScriptFunction((n) => String.fromCodePoint(n));
builtins.ord = wrapJavaScriptFunction((s) => s.codePointAt(0));
builtins["to-string"] = wrapJavaScriptFunction((n) => n.toString());
builtins["to-number"] = wrapJavaScriptFunction((s) => parseInt(s));

1
static/syntax/haku.json
View file

@ -1,6 +1,7 @@
{
"patterns": [
{ "regex": ";.*", "is": "comment" },
{ "regex": "\"[^\"]*\"", "is": "string" },
{ "regex": "[0-9]+", "is": "literal" },
{
"regex": "\\((fn)\\s*\\(.*?\\)",