MathematicalFunction { private static FunctionResolver euler() { return FunctionDSL.define(BuiltinFunctionName.E.getName(), FunctionDSL.impl(() -> new ExprDoubleValue(Math.E), DOUBLE) ); }  static void register(BuiltinFunctionRepository repository);  }
@Test public void test_e() { FunctionExpression e = dsl.euler(); assertThat(e.valueOf(valueEnv()), allOf(hasType(DOUBLE), hasValue(Math.E))); }