feat(plugin): indent try-catch blocks

Indent TRY and CATCH bodies, align CATCH and ENDTRY with their TRY, and
trigger on-type formatting when either keyword is completed. Document the
supported blocks and verify nesting, selection context and Enter indentation.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

2 files changed, 8 insertions, 7 deletions

diff --git a/plugin/src/extension.js b/plugin/src/extension.js
index 70c8622..6bd1255 100644
--- a/plugin/src/extension.js
+++ b/plugin/src/extension.js
@@ -49,11 +49,11 @@ function activate(context) {
 		}),
 		vscode.languages.registerOnTypeFormattingEditProvider(languageId, {
 			provideOnTypeFormattingEdits(document, position, char) {
-				if (char !== '\n' && !/^\s*(?:ELSE|ENDIF|ENDWHILE|UNTIL|NEXT|ENDFUNCTION|ENDPROCEDURE|ENDTYPE)\b/.test(
+				if (char !== '\n' && !/^\s*(?:ELSE|ENDIF|ENDWHILE|UNTIL|NEXT|ENDFUNCTION|ENDPROCEDURE|ENDTYPE|CATCH|ENDTRY)\b/.test(
 					codeOnly(document.lineAt(position.line).text))) return [];
 				return formatLines(document, position.line, position.line, char === '\n');
 			}
-		}, '\n', 'E', 'F', 'L', 'T', 'N')
+		}, '\n', 'E', 'F', 'L', 'T', 'N', 'H', 'Y')
 	);
 	refreshBrackets();
 }
diff --git a/plugin/src/indentation.js b/plugin/src/indentation.js
index c8af770..b7fca78 100644
--- a/plugin/src/indentation.js
+++ b/plugin/src/indentation.js
@@ -3,7 +3,7 @@
 const { codeOnly } = require('./lexical');
 const closers = {
 	ENDIF: 'IF', ENDWHILE: 'WHILE', UNTIL: 'REPEAT', NEXT: 'FOR',
-	ENDFUNCTION: 'FUNCTION', ENDPROCEDURE: 'PROCEDURE', ENDTYPE: 'TYPE'
+	ENDFUNCTION: 'FUNCTION', ENDPROCEDURE: 'PROCEDURE', ENDTYPE: 'TYPE', ENDTRY: 'TRY'
 };
 
 function lineDepths(lines) {
@@ -12,13 +12,14 @@ function lineDepths(lines) {
 	return lines.map(line => {
 		const code = codeOnly(line).trim();
 		const keyword = /^([A-Za-z][A-Za-z0-9_]*)\b/.exec(code)?.[1];
-		if (closers[keyword] || keyword === 'ELSE') {
-			const kind = keyword === 'ELSE' ? 'IF' : closers[keyword];
+		const branch = keyword === 'ELSE' ? 'IF' : keyword === 'CATCH' ? 'TRY' : null;
+		if (closers[keyword] || branch) {
+			const kind = branch || closers[keyword];
 			const index = stack.findLastIndex(block => block.kind === kind);
 			if (index >= 0) {
 				stack.length = index;
 				const current = depth();
-				if (keyword === 'ELSE') stack.push({ kind: 'IF', active: true });
+				if (branch) stack.push({ kind, active: true });
 				return current;
 			}
 			// Incomplete code should still format without negative indentation.
@@ -32,7 +33,7 @@ function lineDepths(lines) {
 		} else if (keyword === 'IF' || keyword === 'WHILE') {
 			stack.push({ kind: keyword, active: new RegExp(
 				keyword === 'IF' ? '\\bTHEN\\b' : '\\bDO\\b').test(code) });
-		} else if (['FOR', 'REPEAT', 'FUNCTION', 'PROCEDURE'].includes(keyword)) {
+		} else if (['FOR', 'REPEAT', 'FUNCTION', 'PROCEDURE', 'TRY'].includes(keyword)) {
 			stack.push({ kind: keyword, active: true });
 		} else if (/^TYPE\s+[A-Za-z][A-Za-z0-9_]*$/.test(code)) {
 			stack.push({ kind: 'TYPE', active: true });