A-line now supports development using Apple's MrC compiler and libraries that ship with MPW, so CodeWarrior is no longer required (though recommended). Unfortunately, SC cannot be supported, as it lacks the -prefix option.
A-line is an MPW-based build system for Mac software. No proprietary project file formats, no Makefiles. A-line uses simple configuration files to specify a project, and then its scripts do the rest.
A-line needs testers, contributors, and more documentation.