Fancy Rules

• Rules can be more complex than just matching file suffixes.
  • The target file can be matched by a regular expression.
  • The source file can be generated from a proc.

rule /^classes/.*\.class$/ => [
  proc { |targ|
    targ.sub(%r{^classes/(.*)\.class}, "src/\1.java")
  }
] do
  java_compile(t.name, t.source)
end