Text-Based DSL

Ruler supports a Wirefilter-style text-based DSL for creating rules using natural, readable syntax. This complements the fluent PHP API—both produce identical results.

Quick Start

use Cline\Ruler\DSL\Wirefilter\StringRuleBuilder;
use Cline\Ruler\Core\Context;

$srb = new StringRuleBuilder;

// Create a rule from text
$rule = $srb->parse('age >= 18 and country == "US"');

// Evaluate with context
$context = new Context(['age' => 25, 'country' => 'US']);
$result = $rule->evaluate($context);  // true

// Add action callback
$rule = $srb->parseWithAction(
    'price + shipping > 100',
    fn() => applyFreeShipping()
);
$rule->execute($context);

Syntax Reference

Comparison Operators

age > 18                    // Greater than
age >= 21                   // Greater than or equal
age < 65                    // Less than
age <= 64                   // Less than or equal
status == "active"          // Loose equality
status != "inactive"        // Loose inequality
role === "admin"            // Strict equality
role !== "guest"            // Strict inequality
country in ["US", "CA"]     // Array membership
role notIn ["banned"]       // Array exclusion

Logical Operators

age >= 18 and country == "US"                    // AND
age >= 21 or country == "US"                     // OR
not (age < 18)                                   // NOT
(age >= 18 and country == "US") or age >= 21     // Parentheses for grouping

Mathematical Operators

price + shipping > 100      // Addition
total - discount < 500      // Subtraction
quantity * price >= 1000    // Multiplication
total / items > 10          // Division
value % 2 == 0              // Modulo

String Operators

Function-style syntax for string operations:

contains(email, "@example.com")                  // String contains
startsWith(username, "admin_")                   // Starts with
endsWith(filename, ".pdf")                       // Ends with
matches(phone, "^\\d{3}-\\d{4}$")                // Regex match

Complex Examples

User Eligibility Check

(user.age >= 18 and user.country in ["US", "CA"]) or
(user.isVerified == true and user.role != "guest")

Pricing Logic

(price + shipping > 100 and user.isPremium == true) or
(price > 200)

Combined Conditions

user.age >= 18 and
country == "US" and
not (status == "banned") and
(subscription == "premium" or purchases > 10)

DSL vs Fluent PHP

Both syntaxes produce identical Operator trees:

DSL Syntax:

$srb = new StringRuleBuilder;
$rule = $srb->parse('age >= 18 and country == "US"');

Fluent PHP:

$rb = new RuleBuilder;
$rule = $rb->create(
    $rb->logicalAnd(
        $rb['age']->greaterThanOrEqualTo(18),
        $rb['country']->equalTo('US')
    )
);

Operator Precedence

From highest to lowest:

1. Parentheses — ()
2. Unary operators — not, -
3. Exponentiation — **
4. Multiplicative — *, /, %
5. Additive — +, -
6. Comparison — >, >=, <, <=
7. Equality — ==, !=, ===, !==
8. Logical AND — and
9. Logical OR — or

Use parentheses for explicit grouping when precedence is unclear.

Variables and Properties

Simple names or dot-notation for nested properties:

age                         // Simple variable
user.age                    // Nested property
http.request.uri.path       // Deeply nested

Type Inference

The DSL automatically infers types:

age > 18                    // Numeric
status == "active"          // String
tags in ["urgent"]          // Array
enabled == true             // Boolean
count == null               // Null

When to Use DSL vs Fluent PHP

Use DSL when:

• Rules are stored as text (database, config files)
• Non-developers need to read/understand rules
• Brevity is important for complex expressions
• Rules are generated from UI forms

Use Fluent PHP when:

• IDE autocomplete is important
• Type safety at the code level is critical
• Rules are built programmatically
• PHP code generation is your workflow

Both approaches coexist seamlessly.