Regex Tester & Validator

This regex parses custom "if" statement blocks in a templating language, matching syntax like `{{@if[variable==value]}}` followed by a content body and an `{{end}}` tag. It captures the left operand, the comparison operator (such as ==, !=, or true/false), the right operand, and the inner content of the block. With the dotall flag enabled, it can match body content that spans across multiple lines. It is highly useful for building simple template engines or custom macro parsers.