README

🪡 Template Strings

for Symfony Expression Language (4-6)

What looks like a dot, a cross and a wave, and does the same thing?

It's the concatenation operator, of course!

PHP uses a dot/period (.), many languages including javascript use +, whereas Symfony Expression Language uses the tilde (~).

This library provides a translation layer on top of Expression Language that converts template strings in ES6 format* to valid expression. While an updated Expression Language subclass is provided for convenience, you don't have to use it, and you can use the provided trait instead.

* only ES6 string interpolation (with any expressions and nesting) is supported; f.e. tagged templates are not.

🔌 Installation

As always, the recommended and easiest way to install this library is through Composer:

composer require "uuf6429/expression-language-tplstring"

🚀 Usage

If you do not plan on extending Symfony Expression Language class, you can use the provided drop-in:

$el = new \uuf6429\ExpressionLanguage\ExpressionLanguageWithTplStr();
$el->evaluate('`hello ${name}!`', ['name'=>'mars']); // => hello mars!

Otherwise, you can subclass the desired Expression Language class and use the provided trait:

class MyEL extends \uuf6429\ExpressionLanguage\ExpressionLanguageWithArrowFunc
{
    use \uuf6429\ExpressionLanguage\TemplateStringTranslatorTrait;
    
    public function compile($expression, array $names = [])
    {
        if (!$expression instanceof \Symfony\Component\ExpressionLanguage\ParsedExpression) {
            $expression = $this->translateTplToEl($expression);
        }

        return parent::compile($expression, $names);
    }

    public function evaluate($expression, array $values = [])
    {
        if (!$expression instanceof \Symfony\Component\ExpressionLanguage\ParsedExpression) {
            $expression = $this->translateTplToEl($expression);
        }

        return parent::evaluate($expression, $values);
    }
}

$el = new MyEL();
$el->evaluate(
    'users.map((user) -> { `hello ${user.name}!` }).join(` `)',
    [
        'users' => new \Illuminate\Support\Collection([
            (object)['name' => 'John', 'surname' => 'Doe'],
            (object)['name' => 'Jane', 'surname' => 'Roe'],
        ])
    ]
); // => hello John! hello Jane!