Class Struct

src/test/java/net/starlark/java/eval/ScriptTest.java:357–392

  // A trivial struct-like class with Starlark fields defined by a map.
  private static class Struct implements StarlarkValue, Structure {
    final Map<String, Object> fields;

    Struct(Map<String, Object> fields) {
      this.fields = fields;
    }

    @Override
    public ImmutableList<String> getFieldNames() {
      return ImmutableList.copyOf(fields.keySet());
    }

    @Override
    public Object getValue(String name) {
      return fields.get(name);
    }

    @Override
    public String getErrorMessageForUnknownField(String name) {
      return null;
    }

    @Override
    public void repr(Printer p) {
      // This repr function prints only the fields.
      // Any methods are still accessible through dir/getattr/hasattr.
      p.append(Starlark.type(this));
      p.append("(");
      String sep = "";
      for (Map.Entry<String, Object> e : fields.entrySet()) {
        p.append(sep).append(e.getKey()).append(" = ").repr(e.getValue());
        sep = ", ";
      }
      p.append(")");
    }
  }

  @StarlarkBuiltin(name = "struct")
  private static class ImmutableStruct extends Struct {