How the Flex compiler defines command line options is not particularly easy to discover. In the flex2.compiler.config.ConfigurationBuffer class, the compiler seems to use reflection to look for method names in the flex2.compiler.common.CompilerConfiguration class that follow specific naming conventions. Using these discovered methods, ConfigurationBuffer extracts the names of the available command line options at runtime.
For example, the --compiler.theme option is defined by adding the following two functions to the CompilerConfiguration class:
public void cfgTheme( ConfigurationValue cv, List paths ) throws ConfigurationException
public static ConfigurationInfo getThemeInfo()