Overview

Notch is designed to live inside the Java ecosystem. JVM classes, methods, and properties are first-class values in Notch code.

Calling methods

java.lang.System.out.println("hello!")

When more than one overload of a method exists, Notch picks the best match by parameter count, then by direct argument-type assignability, then by whether a registered coercion can bridge the argument type to the parameter type. Less-specific matches lose to more-specific ones.

Constructors

Call a constructor by invoking the type value:

list = java.util.ArrayList()
list.add("a")
list.add("b")
list.size       # 2

Constructor overload resolution uses the same getBestMatch logic as method invocation.

Null handling

A property access or method call on null produces a diagnostic error message that points at the failing expression, rather than throwing a NullPointerException from inside the runtime. Use is empty or compare against null explicitly to guard.

Property access

Property access works on JVM objects via their getter methods. Both bean-style and direct field names are accepted.

list = [1, 2, 3]
list.size      # 3
list.size()    # 3, same thing

Snake-case and camelCase access both resolve to the same property:

java.lang.Object.displayName
java.lang.Object.display_name

Type resolution

Fully-qualified class names resolve to type values:

java.lang.String

Returns a NotchType describing the class.

JVM primitives are accessible as bare identifiers:

int

Static methods

java.util.List.of(1, 2, 3)

Static properties

java.lang.Character.TYPE

Iterating an enum

Java enums iterate via the values static accessor:

for v in java.time.DayOfWeek.values
  print(v)
end

The runtime special-cases enums in its iterable coercion, so values works without an explicit call.

See also

• Coercions for how Notch lets int flow into long-typed parameters.
• Closures for converting Notch closures into Java functional interfaces.