HOL-master/examples/lassie/sempre/src/edu/stanford/nlp/sempre/IdentityFn.java
package edu.stanford.nlp.sempre;

/**
 * Identity function.
 *
 * @author Percy Liang
 */
public class IdentityFn extends SemanticFn {
  public DerivationStream call(Example ex, final Callable c) {
    return new SingleDerivationStream() {
      @Override
      public Derivation createDerivation() {
        return new Derivation.Builder()
                .withCallable(c)
                .withFormulaFrom(c.child(0))
                .createDerivation();
      }
    };
  }
}
