Regex Editor & Tester

This regex matches C preprocessor macro definitions, specifically function-like macros in the form #define NAME(arg1, arg2) body. It captures the macro name, the first parameter, an optional second parameter, and the macro body. The pattern allows spaces around tokens and anchors to the start of the line (after optional leading spaces). Useful for scanning C source files to extract macro signatures for documentation, analysis, or refactoring tools.