Template Language Overview

Folio's template language gives you a clean way to describe documents without mixing design with application logic. Templates are compiled to PHP closures, then rendered with a plain data array.

Why Use Templates?

• Separation of concerns — designers own the .folio file; developers own the data.
• No runtime interpreter — templates compile to native PHP, so performance is the same as using the builder API directly.
• Static analysis friendly — generated code is type-checked by PHP and can be cached on disk.
• First-class tooling — the formatter, LSP, VS Code extension, and Tree-sitter grammar all understand the same grammar.

A Minimal Template

var title = "Quarterly Report"

page {
  heading title
  text "Prepared for internal review."
}

use Folio\Pdf\Template\PhpTemplateCompiler;

$compiler = new PhpTemplateCompiler();
$pdf = $compiler->render(file_get_contents('report.folio'), [
    'title' => 'Q4 2024',
]);

$pdf->save('report.pdf');

render() returns a Folio\Pdf\Document\Pdf instance. You can call save(), toString(), or toBytes() on it.

How It Works

1. Lexer reads the .folio source and produces tokens.
2. Parser builds an AST from those tokens.
3. Compiler walks the AST and emits a PHP closure.
4. Runtime executes the closure with your data and returns a Pdf.

The compiled output is plain PHP. You can inspect it, commit it, or cache it alongside your templates.

Next Steps

• Syntax Reference
• Elements
• Control Flow
• Directives