Fix Ruby predicate and bang method highlighting

Syntax/Language/ruby.js

@@ -4,11 +4,15 @@ import {Match} from '../Match.js';
 
 const language = new Language('ruby');
 
-// Ruby-style function definitions and method calls (def foo, .bar)
-// Method names can end with ? or !
+// Ruby-style function definitions and method calls (def foo, .bar).
+// Predicate and bang methods are also unambiguous without a receiver or arguments.
 const rubyStyleFunction = {
-	pattern: /(?:def\s+|\.)([a-z_][a-z0-9_]*[?!]?)/i,
-	matches: Rule.extractMatches({type: 'function'})
+	pattern:
+		/(?:def\s+|\.)([a-z_][a-z0-9_]*[?!]?)|(^|[^\w.:])([a-z_][a-z0-9_]*[?!])(?!:)/i,
+	matches: Rule.extractMatches(
+		{index: 1, type: 'function'},
+		{index: 3, type: 'function'}
+	)
 };
 
 // Emulate negative lookbehind to avoid matching ::symbol (only match :symbol not ::symbol)

test/Syntax/Language/ruby.js

@@ -1,6 +1,6 @@
 import Syntax from '../../../Syntax.js';
 import registerRuby from '../../../Syntax/Language/ruby.js';
-import {strictEqual} from 'node:assert';
+import {deepStrictEqual, strictEqual} from 'node:assert';
 import test from 'node:test';
 
 async function getTypesFor(code) {
@@ -68,3 +68,28 @@ test('Ruby: function detection', async () => {
 	const types = await getTypesFor('def compute\nend\nobject.method');
 	strictEqual(types.includes('function'), true);
 });
+
+test('Ruby: predicate and bang method detection', async () => {
+	const syntax = new Syntax();
+	registerRuby(syntax);
+	const language = await syntax.getLanguage('ruby');
+	const matches = await language.getMatches(
+		syntax,
+		'def valid?\nend\nobject.save!\nvalid?(value)\nsave! value\nready?'
+	);
+	const functions = matches
+		.filter(match => match.expression.type === 'function')
+		.map(match => match.value);
+
+	deepStrictEqual(functions, ['valid?', 'save!', 'valid?', 'save!', 'ready?']);
+});
+
+test('Ruby: predicate and bang symbols are not methods', async () => {
+	const syntax = new Syntax();
+	registerRuby(syntax);
+	const language = await syntax.getLanguage('ruby');
+	const matches = await language.getMatches(syntax, ':valid?\n:save!\nvalid?: true');
+	const functions = matches.filter(match => match.expression.type === 'function');
+
+	deepStrictEqual(functions, []);
+});