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tree-sitter-scl/grammar.js
2025-08-27 01:29:54 -04:00

108 lines
2.2 KiB
JavaScript

/**
* @file SCL grammar for tree-sitter
* @author Jacob Signorovitch <jacob.signorovitch@gmail.com>
* @license MIT
*/
/// <reference types="tree-sitter-cli/dsl" />
// @ts-check
module.exports = grammar({
name: "scl",
conflicts: ($) => [[$.params, $._exp]],
rules: {
source_file: ($) => repeat($._exp),
_exp: ($) =>
choice(
$.num,
$.bool,
$.word,
$.binexp,
$.callexp,
$.parexp,
$.block,
$.vardef,
$.lambda,
$.funcdef,
$.ifexp,
),
num: (_) => /\d+/,
bool: (_) => choice("TRUE", "T", "FALSE", "F"),
word: (_) => /[a-zA-Z_]\w*/,
binexp: ($) =>
prec.left(
1,
seq(
field("left", $._exp),
field("op", choice("+", "-", "*", "/", "eq")),
field("right", $._exp),
),
),
callexp: ($) =>
prec.left(
1, // lower than funcdef
seq(field("fn", $.word), "(", optional(commaSep($._exp)), ")"),
),
parexp: ($) => seq("(", $._exp, ")"),
block: ($) => seq("{", repeat($._exp), "}"),
vardef: ($) =>
prec.right(1, seq(field("name", $.word), "=", field("value", $._exp))),
lambda: ($) =>
prec.right(
2,
seq("\\", field("params", $.params), field("body", $._exp)),
),
funcdef: ($) =>
prec.right(
3, // higher precedence than call
seq(
field("name", $.word),
field("params", $.params),
field("body", $._exp),
),
),
params: ($) => seq("(", optional(commaSep($.word)), ")"),
ifexp: ($) =>
choice(
seq(
"_if",
"(",
field("cond", $._exp),
",",
field("then", $._exp),
",",
field("else", $._exp),
")",
),
seq(
"if",
field("cond", $._exp),
field("then", $._exp),
choice(seq("else", field("else", $._exp)), field("else", $._exp)),
),
seq(
"?",
field("cond", $._exp),
field("then", $._exp),
field("else", $._exp),
),
),
},
});
function commaSep(rule) {
return seq(rule, repeat(seq(",", rule)));
}