fj-yaml

Is a pretty uncomfortable mashup of Functional Java and jvyaml

Usage

For some yaml like this:

---
regions:
- region_id: 1
  formats:
  - format_id: 1
    weights:
      H: 3
      M: 2
      L: 1
    signs: [3, 101, 102, 103, 104]
  - format_id: 2
    weights:
      H: 4
      M: 2
      L: 1
    signs: [9, 202, 203, 204]
- region_id: 2
  formats:
  - format_id: 1
    weights:
      H: 5
      M: 3
      L: 2
    signs: [3, 9, 302, 303, 304, 305]

You can do this java:

public enum Weight {
    L, M, H
}  
  
public static final F<Object, Weight> WEIGHT = new F<Object, Weight>() {
    public Weight f(final Object o) {
        return Weight.valueOf((String) o);
    }
};
  
public SomeResult parse(final String s) {
    final List<P2<Integer, List<P3<Integer, Map<Weight,Integer>, List<Integer>>>>> regions =
        namedEntries(
              p("regions", yamlToList(namedEntries(
                      p("region_id", INT),
                      p("formats", yamlToList(namedEntries(
                              p("format_id", INT),
                              p("weights", yamlToMap(WEIGHT, INT)),
                              p("signs", yamlToList(INT))))
                      )
              )))
        ).f(YAML.load(s))._1();
    return new SomeResult(regions);
}    

So, nesting of P2s and P3s and java.util.List objects, all generically typed and guaranteed* to fail eagerly.

*not a guarantee