From 3026a37268a3b01a7e3d2c2a4680282d4bb0c026 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Mon, 16 Jun 2025 21:29:22 -0400
Subject: [PATCH] more

---
 packages/svelte/src/compiler/print/index.js | 357 +++++++++++++++++++-
 packages/svelte/tests/parser-modern/test.ts |  48 ++-
 2 files changed, 371 insertions(+), 34 deletions(-)

diff --git a/packages/svelte/src/compiler/print/index.js b/packages/svelte/src/compiler/print/index.js
index bf17b4c1e6..7e77da73d8 100644
--- a/packages/svelte/src/compiler/print/index.js
+++ b/packages/svelte/src/compiler/print/index.js
@@ -2,6 +2,7 @@
 /** @import { Visitors } from 'esrap' */
 import * as esrap from 'esrap';
 import ts from 'esrap/languages/ts';
+import { is_void } from '../../utils.js';
 
 /**
  * @param {AST.SvelteNode} ast
@@ -19,24 +20,34 @@ export function print(ast) {
 const visitors = {
 	Root(node, context) {
 		if (node.options) {
-			throw new Error('TODO');
+			context.write('<svelte:options');
+
+			for (const attribute of node.options.attributes) {
+				context.write(' ');
+				context.visit(attribute);
+			}
+
+			context.write(' />');
 		}
 
+		let started = false;
+
 		for (const item of [node.module, node.instance, node.fragment, node.css]) {
 			if (!item) continue;
 
-			context.margin();
-			context.newline();
+			if (started) {
+				context.margin();
+				context.newline();
+			}
+
 			context.visit(item);
+			started = true;
 		}
 	},
+
 	Script(node, context) {
 		context.write('<script');
 
-		if (node.context === 'module') {
-			context.write(' module');
-		}
-
 		for (const attribute of node.attributes) {
 			context.write(' ');
 			context.visit(attribute);
@@ -52,6 +63,7 @@ const visitors = {
 
 		context.write('</script>');
 	},
+
 	Fragment(node, context) {
 		for (let i = 0; i < node.nodes.length; i += 1) {
 			const child = node.nodes[i];
@@ -68,6 +80,25 @@ const visitors = {
 			}
 		}
 	},
+
+	Atrule(node, context) {
+		context.write(`@${node.name}`);
+		if (node.prelude) context.write(` ${node.prelude}`);
+
+		if (node.block) {
+			context.write(' ');
+			context.visit(node.block);
+		} else {
+			context.write(';');
+		}
+	},
+
+	AttachTag(node, context) {
+		context.write('{@attach ');
+		context.visit(node.expression);
+		context.write('}');
+	},
+
 	Attribute(node, context) {
 		context.write(node.name);
 
@@ -91,14 +122,159 @@ const visitors = {
 			context.visit(node.value);
 		}
 	},
-	Text(node, context) {
-		context.write(node.data);
+
+	AwaitBlock(node, context) {
+		context.write(`{#await `);
+		context.visit(node.expression);
+
+		if (node.pending) {
+			context.write('}');
+			context.visit(node.pending);
+			context.write('{:');
+		} else {
+			context.write(' ');
+		}
+
+		if (node.then) {
+			context.write(node.value ? 'then ' : 'then');
+			if (node.value) context.visit(node.value);
+			context.write('}');
+			context.visit(node.then);
+
+			if (node.catch) {
+				context.write('{:');
+			}
+		}
+
+		if (node.catch) {
+			context.write(node.value ? 'catch ' : 'catch');
+			if (node.error) context.visit(node.error);
+			context.write('}');
+			context.visit(node.catch);
+		}
+
+		context.write('{/await}');
+	},
+
+	BindDirective(node, context) {
+		context.write(`bind:${node.name}`);
+
+		if (node.expression.type === 'Identifier' && node.expression.name === node.name) {
+			// shorthand
+			return;
+		}
+
+		context.write('={');
+
+		if (node.expression.type === 'SequenceExpression') {
+			context.visit(node.expression.expressions[0]);
+			context.write(', ');
+			context.visit(node.expression.expressions[1]);
+		} else {
+			context.visit(node.expression);
+		}
+
+		context.write('}');
+	},
+
+	Block(node, context) {
+		context.write('{');
+
+		if (node.children.length > 0) {
+			context.indent();
+			context.newline();
+
+			let started = false;
+
+			for (const child of node.children) {
+				if (started) {
+					context.margin();
+					context.newline();
+				}
+
+				context.visit(child);
+
+				started = true;
+			}
+
+			context.dedent();
+			context.newline();
+		}
+
+		context.write('}');
+	},
+
+	ClassSelector(node, context) {
+		context.write(`.${node.name}`);
+	},
+
+	Comment(node, context) {
+		context.write('<!--' + node.data + '-->');
+	},
+
+	ComplexSelector(node, context) {
+		for (const selector of node.children) {
+			context.visit(selector);
+		}
+	},
+
+	Component(node, context) {
+		context.write(`<${node.name}`);
+
+		for (let i = 0; i < node.attributes.length; i += 1) {
+			context.write(' ');
+			context.visit(node.attributes[i]);
+		}
+
+		if (node.fragment.nodes.length > 0) {
+			context.write('>');
+			context.visit(node.fragment);
+			context.write(`</${node.name}>`);
+		} else {
+			context.write(' />');
+		}
+	},
+
+	Declaration(node, context) {
+		context.write('foo: bar;');
+	},
+
+	EachBlock(node, context) {
+		context.write('{#each ');
+		context.visit(node.expression);
+
+		if (node.context) {
+			context.write(' as ');
+			context.visit(node.context);
+		}
+
+		if (node.index) {
+			context.write(`, ${node.index}`);
+		}
+
+		if (node.key) {
+			context.write(' (');
+			context.visit(node.key);
+			context.write(')');
+		}
+
+		context.write('}');
+		context.visit(node.body);
+
+		if (node.fallback) {
+			context.write('{:else}');
+			context.visit(node.fallback);
+		}
+
+		context.write('{/each}');
 	},
+
 	ExpressionTag(node, context) {
 		context.write('{');
 		context.visit(node.expression);
 		context.write('}');
 	},
+
 	IfBlock(node, context) {
 		context.write('{#if ');
 		context.visit(node.test);
@@ -110,6 +286,41 @@ const visitors = {
 
 		context.write('{/if}');
 	},
+
+	Nth(node, context) {
+		context.write(node.value); // TODO is this right?
+	},
+
+	OnDirective(node, context) {
+		// TODO
+	},
+
+	PseudoClassSelector(node, context) {
+		context.write(`:${node.name}`);
+
+		if (node.args) {
+			context.write('(');
+
+			let started = false;
+
+			for (const arg of node.args.children) {
+				if (started) {
+					context.write(', ');
+				}
+
+				context.visit(arg);
+
+				started = true;
+			}
+
+			context.write(')');
+		}
+	},
+
+	PseudoElementSelector(node, context) {
+		context.write(`::${node.name}`);
+	},
+
 	RegularElement(node, context) {
 		context.write('<' + node.name);
 
@@ -119,22 +330,134 @@ const visitors = {
 			context.visit(attribute);
 		}
 
-		context.write('>');
+		if (is_void(node.name)) {
+			context.write(' />');
+		} else {
+			context.write('>');
+
+			if (node.fragment) {
+				context.visit(node.fragment);
+				context.write(`</${node.name}>`);
+			}
+		}
+	},
+
+	RelativeSelector(node, context) {
+		if (node.combinator) {
+			if (node.combinator.name === ' ') {
+				context.write(' ');
+			} else {
+				context.write(` ${node.combinator.name} `);
+			}
+		}
+
+		for (const selector of node.selectors) {
+			context.visit(selector);
+		}
+	},
+
+	RenderTag(node, context) {
+		context.write('{@render ');
+		context.visit(node.expression);
+		context.write('}');
+	},
+
+	Rule(node, context) {
+		let started = false;
+
+		for (const selector of node.prelude.children) {
+			if (started) {
+				context.write(',');
+				context.newline();
+			}
+
+			context.visit(selector);
+			started = true;
+		}
+
+		context.write(' ');
+		context.visit(node.block);
+	},
+
+	SlotElement(node, context) {
+		context.write('<slot');
+
+		for (let i = 0; i < node.attributes.length; i += 1) {
+			context.write(' ');
+			context.visit(node.attributes[i]);
+		}
 
-		// TODO handle void elements
-		if (node.fragment) {
+		if (node.fragment.nodes.length > 0) {
+			context.write('>');
 			context.visit(node.fragment);
+			context.write('</slot>');
+		} else {
+			context.write(' />');
 		}
+	},
 
-		context.write(`</${node.name}>`);
+	SnippetBlock(node, context) {
+		context.write('{#snippet ');
+		context.visit(node.expression);
+
+		if (node.typeParams) {
+			context.write(`<${node.typeParams}>`);
+		}
+
+		context.write('(');
+
+		for (let i = 0; i < node.parameters.length; i += 1) {
+			if (i > 0) context.write(', ');
+			context.visit(node.parameters[i]);
+		}
+
+		context.write(')}');
+		context.visit(node.body);
+		context.write('{/snippet}');
 	},
-	OnDirective(node, context) {
-		// TODO
+
+	StyleSheet(node, context) {
+		context.write('<style');
+
+		for (const attribute of node.attributes) {
+			context.write(' ');
+			context.visit(attribute);
+		}
+
+		context.write('>');
+
+		if (node.children.length > 0) {
+			context.indent();
+			context.newline();
+
+			let started = false;
+
+			for (const child of node.children) {
+				if (started) {
+					context.margin();
+					context.newline();
+				}
+
+				context.visit(child);
+				started = true;
+			}
+
+			context.dedent();
+			context.newline();
+		}
+
+		context.write('</style>');
+	},
+
+	Text(node, context) {
+		context.write(node.data);
 	},
+
 	TransitionDirective(node, context) {
 		// TODO
 	},
-	Comment(node, context) {
-		// TODO
+
+	TypeSelector(node, context) {
+		context.write(node.name);
 	}
 };
diff --git a/packages/svelte/tests/parser-modern/test.ts b/packages/svelte/tests/parser-modern/test.ts
index 08d8aafeab..da9119441a 100644
--- a/packages/svelte/tests/parser-modern/test.ts
+++ b/packages/svelte/tests/parser-modern/test.ts
@@ -8,6 +8,8 @@ import { walk } from 'zimmerframe';
 interface ParserTest extends BaseTest {}
 
 const { test, run } = suite<ParserTest>(async (config, cwd) => {
+	const loose = cwd.split('/').pop()!.startsWith('loose-');
+
 	const input = fs
 		.readFileSync(`${cwd}/input.svelte`, 'utf-8')
 		.replace(/\s+$/, '')
@@ -22,6 +24,8 @@ const { test, run } = suite<ParserTest>(async (config, cwd) => {
 		)
 	);
 
+	delete actual.comments;
+
 	// run `UPDATE_SNAPSHOTS=true pnpm test parser` to update parser tests
 	if (process.env.UPDATE_SNAPSHOTS) {
 		fs.writeFileSync(`${cwd}/output.json`, JSON.stringify(actual, null, '\t'));
@@ -32,27 +36,37 @@ const { test, run } = suite<ParserTest>(async (config, cwd) => {
 		assert.deepEqual(actual, expected);
 	}
 
-	const printed = print(actual);
-	const reparsed = JSON.parse(
-		JSON.stringify(
-			parse(printed.code, {
-				modern: true,
-				loose: cwd.split('/').pop()!.startsWith('loose-')
-			})
-		)
-	);
+	if (!loose) {
+		const printed = print(actual);
+		const reparsed = JSON.parse(
+			JSON.stringify(
+				parse(printed.code, {
+					modern: true,
+					loose
+				})
+			)
+		);
 
-	fs.writeFileSync(`${cwd}/_actual.svelte`, JSON.stringify(printed.code, null, '\t'));
+		fs.writeFileSync(`${cwd}/_actual.svelte`, printed.code);
 
-	const actual_cleaned = walk(actual, null, {
-		_(node, context) {}
-	});
+		const actual_cleaned = walk(actual, null, {
+			_(node, context) {
+				delete node.loc;
+				context.next();
+			}
+		});
 
-	const reparsed_cleaned = walk(actual, null, {
-		_(node, context) {}
-	});
+		delete reparsed.comments;
 
-	assert.deepEqual(actual_cleaned, reparsed_cleaned);
+		const reparsed_cleaned = walk(reparsed, null, {
+			_(node, context) {
+				delete node.loc;
+				context.next();
+			}
+		});
+
+		assert.deepEqual(actual_cleaned, reparsed_cleaned);
+	}
 });
 
 export { test };