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I gave up on the no precedence thing. adding prec to parser

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Dustin Swan 2026-02-12 17:58:21 -07:00
parent 44015e58b1
commit 2570635ba5
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GPG key ID: 30D46587E2100467
2 changed files with 33 additions and 9 deletions
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36
src/parser.ts
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@ -86,6 +86,33 @@ export class Parser {
}
}
private precOf(token: Token): number {
switch (token.kind) {
case 'ampersand':
return 1;
case 'equals-equals':
case 'not-equals':
case 'greater-than':
case 'greater-equals':
case 'less-than':
case 'less-equals':
return 2;
case 'plus':
case 'minus':
return 3;
case 'star':
case 'slash':
case 'percent':
return 4;
case 'caret':
return 5;
case 'tilde':
return 6;
default:
return 0;
}
}
private canStartPrimary(): boolean {
const kind = this.current().kind;
return kind === 'ident' || kind === 'type-ident' ||
@ -344,16 +371,17 @@ export class Parser {
return { kind: 'let', name, value, body, ...this.getPos(nameToken) };
}
private parseInfix(): AST {
private parseInfix(minPrec: number = 0): AST {
const token = this.current();
let left = this.parseApplication();
while (this.isInfixOp()) {
while (this.isInfixOp() && this.precOf(this.current()) >= minPrec) {
const opToken = this.advance();
const prec = this.precOf(opToken);
if (opToken.kind === 'tilde') {
// function application operator
const right = this.parseApplication();
const right = this.parseInfix(prec + 1);
left = {
kind: 'apply',
@ -364,7 +392,7 @@ export class Parser {
} else {
// operators desugar to function calls
const opName = this.tokenToOpName(opToken);
const right = this.parseApplication();
const right = this.parseInfix(prec + 1);
left = {
kind: 'apply',