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BREAKING: proper support for closures #8

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10 changes: 5 additions & 5 deletions static/index.html
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Original file line number Diff line number Diff line change
Expand Up @@ -4,8 +4,8 @@
<title>Tabloid: the clickbait headline programming language</title>
<meta name="viewport" content="width=device-width,initial-scale=1">
<link href="https://fonts.googleapis.com/css2?family=Alfa+Slab+One&family=IBM+Plex+Mono&family=IBM+Plex+Sans:wght@400;700&display=swap" rel="stylesheet">
<link rel="stylesheet" href="/css/blocks.min.css">
<link rel="stylesheet" href="/css/main.css">
<link rel="stylesheet" href="./css/blocks.min.css">
<link rel="stylesheet" href="./css/main.css">

<!-- fb -->
<meta property="og:url" content="https://tabloid.thesephist.vercel.app" />
Expand All @@ -21,7 +21,7 @@

<body>
<noscript>Oops, please turn on JavaScript to enjoy Tabloid :)</noscript>
<script src="/js/torus.min.js"></script>
<script src="/js/lang.js"></script>
<script src="/js/main.js"></script>
<script src="./js/torus.min.js"></script>
<script src="./js/lang.js"></script>
<script src="./js/main.js"></script>
</body>
190 changes: 109 additions & 81 deletions static/js/lang.js
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Original file line number Diff line number Diff line change
Expand Up @@ -41,7 +41,7 @@ class Reader {
}
}

/**
/**
* Split into words for easier tokenization
* with keywords.
*/
Expand Down Expand Up @@ -77,7 +77,7 @@ class Wordifier {
// read until WS
this.reader.backstep();
this.tokens.push(this.reader.readUntil(c => {
return !c.trim() || ['(', ')', ','].includes(c)
return !c.trim() || ['(', ')', ','].includes(c);
}));
}
}
Expand All @@ -103,6 +103,7 @@ const T = {
RParen: Symbol('RParen'),
Comma: Symbol('Comma'),
DiscoverHowTo: Symbol('DiscoverHowTo'),
Breaking: Symbol('Breaking'),
With: Symbol('With'),
Of: Symbol('Of'),
RumorHasIt: Symbol('RumorHasIt'),
Expand All @@ -127,7 +128,7 @@ const T = {
SmallerThan: Symbol('SmallerThan'), // <
ShockingDevelopment: Symbol('ShockingDevelopment'),
PleaseLikeAndSubscribe: Symbol('PleaseLikeAndSubscribe'),
}
};

const BINARY_OPS = [
T.IsActually,
Expand Down Expand Up @@ -155,6 +156,10 @@ function tokenize(prog) {
tokens.push(T.DiscoverHowTo);
break;
}
case 'BREAKING': {
tokens.push(T.Breaking);
break;
}
case 'WITH': {
tokens.push(T.With);
break;
Expand Down Expand Up @@ -364,24 +369,37 @@ class Parser {
}
throw new Error(`Parsing error: expected identifier, got ${ident.toString()}`);
}
readFnArgs() {
let args = [];
if (this.tokens.peek(T.With)) {
this.tokens.next(); // with
// with args
args.push(this.expectIdentString());
while (this.tokens.peek() === T.Comma) {
this.tokens.next(); // comma
args.push(this.expectIdentString());
}
}
return args;
}
atom() {
const next = this.tokens.next();
if (typeof next === 'number') {
return {
type: N.NumberLiteral,
val: next,
}
};
} else if (typeof next === 'string') {
if (next.startsWith('"')) {
return {
type: N.StringLiteral,
val: next.substr(1),
}
};
}
const ident = {
type: N.Ident,
val: next,
}
};
if (this.tokens.peek() === T.Of) {
return this.fnCall(ident);
}
Expand All @@ -390,37 +408,25 @@ class Parser {
return {
type: N.BoolLiteral,
val: true,
}
};
} else if (next === T.CompletelyWrong) {
return {
type: N.BoolLiteral,
val: false,
}
};
} else if (next === T.DiscoverHowTo) {
// fn literal
const fnName = this.tokens.next();
if (this.tokens.peek(T.With)) {
this.tokens.next(); // with
// with args
const args = [this.expectIdentString()];
while (this.tokens.peek() === T.Comma) {
this.tokens.next(); // comma
args.push(this.expectIdentString());
}
return {
type: N.FnDecl,
name: fnName,
args: args,
body: this.expr(),
}
} else {
return {
type: N.FnDecl,
name: fnName,
args: [],
body: this.expr(),
}
}
return {
type: N.FnDecl,
name: this.tokens.next(),
args: this.readFnArgs(),
body: this.expr(),
};
} else if (next === T.Breaking) {
return {
type: N.FnDecl,
args: this.readFnArgs(),
body: this.expr(),
};
} else if (next === T.RumorHasIt) {
// block
const exprs = [];
Expand Down Expand Up @@ -466,7 +472,7 @@ class Parser {
cond: cond,
ifBody: ifBody,
elseBody: elseBody,
}
};
} else if (next === T.ExpertsClaim) {
// assignment
const name = this.expectIdentString();
Expand All @@ -476,30 +482,30 @@ class Parser {
type: N.Assignment,
name,
val,
}
};
} else if (next === T.ShockingDevelopment) {
// return
return {
type: N.ReturnExpr,
val: this.expr(),
}
};
} else if (next === T.PleaseLikeAndSubscribe) {
// prog end
return {
type: N.ProgEndExpr,
}
};
} else if (next === T.YouWontWantToMiss) {
// print expr
return {
type: N.PrintExpr,
val: this.expr(),
}
};
} else if (next === T.LatestNewsOn) {
// input expr
return {
type: N.InputExpr,
val: this.expr(),
}
};
}

this.tokens.backstep();
Expand All @@ -514,7 +520,7 @@ class Parser {
op,
left,
right,
}
};
}

return atom;
Expand All @@ -530,7 +536,7 @@ class Parser {
type: N.FnCall,
fn: fnNode,
args: args,
}
};
}
}

Expand All @@ -549,47 +555,80 @@ class ReturnError {
}

class Environment {
constructor(runtime) {
/**
* Runtime contains the following functions:
* - print(s)
* - input(s)
*/
this.runtime = runtime;
this.scopes = [{}]; // begin with global scope
constructor(parent) {
this.vars = Object.create(parent ? parent.vars : null);
this.parent = parent;
if (parent) {
/**
* Runtime contains the following functions:
* - print(s)
* - input(s)
*/
this.runtime = parent.runtime;
}
}
extend() {
return new Environment(this);
}
lookup(name) {
let scope = this;
while (scope) {
if (Object.prototype.hasOwnProperty.call(scope.vars, name))
return scope;
scope = scope.parent;
}
}
get(name) {
if (name in this.vars)
return this.vars[name];
throw new Error("Undefined variable " + name);
}
set(name, value) {
let scope = this.lookup(name);
if (!scope && this.parent)
throw new Error("Undefined variable " + name);
return (scope || this).vars[name] = value;
}
def(name, value) {
return this.vars[name] = value;
}
run(nodes) {

run(nodes, runtime) {
this.runtime = runtime;
let rv;
for (const node of nodes) {
rv = this.eval(node);
}
return rv;
}
eval(node) {
const scope = this.scopes[this.scopes.length - 1];

switch (node.type) {
case N.NumberLiteral:
case N.StringLiteral:
case N.BoolLiteral:
return node.val;
case N.FnDecl: {
scope[node.name] = node;
return node;
let closure = {
env: this,
node: node
};
if (node.name) {
this.def(node.name, closure);
}
return closure;
}
case N.FnCall: {
const fn = this.eval(node.fn);
const args = node.args.map(arg => this.eval(arg));

const calleeScope = {};
fn.args.forEach((argName, i) => {
calleeScope[argName] = args[i];
const calleeEnv = fn.env.extend();
fn.node.args.forEach((argName, i) => {
calleeEnv.def(argName, args[i]);
});

this.scopes.push(calleeScope);
let rv;
try {
this.eval(fn.body);
calleeEnv.eval(fn.node.body);
} catch (maybeReturnErr) {
if (maybeReturnErr instanceof ReturnError) {
rv = maybeReturnErr.unwrap();
Expand All @@ -598,48 +637,37 @@ class Environment {
throw maybeReturnErr;
}
}
this.scopes.pop();

return rv;
}
case N.Ident: {
let i = this.scopes.length - 1;
while (i >= 0) {
if (node.val in this.scopes[i]) {
return this.scopes[i][node.val];
}
i --;
}
throw new Error(`Runtime error: Undefined variable "${node.val}"`);
return this.get(node.val);
}
case N.Assignment: {
scope[node.name] = this.eval(node.val);
return scope[node.name];
return this.set(node.name, this.eval(node.val));
}
case N.BinaryOp: {
const left = this.eval(node.left);
const right = this.eval(node.right);
switch (node.op) {
case T.IsActually:
return left === right;
return this.eval(node.left) === this.eval(node.right);
case T.And:
return left && right;
return this.eval(node.left) && this.eval(node.right);
case T.Or:
return left || right;
return this.eval(node.left) || this.eval(node.right);
case T.Plus:
return left + right;
return this.eval(node.left) + this.eval(node.right);
case T.Minus:
return left - right;
return this.eval(node.left) - this.eval(node.right);
case T.Times:
return left * right;
return this.eval(node.left) * this.eval(node.right);
case T.DividedBy:
return left / right;
return this.eval(node.left) / this.eval(node.right);
case T.Modulo:
return left % right;
return this.eval(node.left) % this.eval(node.right);
case T.Beats:
return left > right;
return this.eval(node.left) > this.eval(node.right);
case T.SmallerThan:
return left < right;
return this.eval(node.left) < this.eval(node.right);
default:
throw new Error(`Runtime error: Unknown binary op ${node.op.toString()}`);
}
Expand Down
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