// TrimFunc represents TRIM sql function
type TrimFunc struct {
	TrimWhere *string      `parser:" \"TRIM\" \"(\" ( @( \"LEADING\" | \"TRAILING\" | \"BOTH\" ) "`
	TrimChars *PrimaryTerm `parser:"             @@?  "`
	TrimFrom  *PrimaryTerm `parser:"             \"FROM\" )? @@ \")\" "`
}

// DateAddFunc represents the DATE_ADD function
type DateAddFunc struct {

		if cerr != nil {
			return nil, cerr
		}
		inferTypeAsString(charsV)
		chars, ok = charsV.ToString()
		if !ok {
			return nil, errNonStringTrimArg
		}
	}

	fromV, ferr := e.TrimFrom.evalNode(r, tableAlias)
	if ferr != nil {
		return nil, ferr
	}
	inferTypeAsString(fromV)
	from, ok := fromV.ToString()
	if !ok {
		return nil, errNonStringTrimArg
	}

  }

  // enum singleton pattern
  private enum TrimStringFunction implements Function<String, String> {
    INSTANCE;

    @Override
    public String apply(String string) {
      return whitespace().trimFrom(string);
    }
  }

  public void testCompose() {
    Function<String, String> trim = TrimStringFunction.INSTANCE;
    Predicate<String> equalsFoo = Predicates.equalTo("Foo");

  }

  // enum singleton pattern
  private enum TrimStringFunction implements Function<String, String> {
    INSTANCE;

    @Override
    public String apply(String string) {
      return whitespace().trimFrom(string);
    }
  }

  public void testCompose() {
    Function<String, String> trim = TrimStringFunction.INSTANCE;
    Predicate<String> equalsFoo = Predicates.equalTo("Foo");