Dot selection

 Koka is a function-oriented language where functions and data form the core of the language (in contrast to objects for example). In particular, the expression s.encode(3) does not select the encode method from the string object, but it is simply syntactic sugar for the function call encode(s,3) where s becomes the first argument. Similarly, c.int converts a character to an integer by calling int(c) (and both expressions are equivalent). The dot notation is intuïtive and quite convenient to chain multiple calls together, as in:

fun showit( s : string )
  s.encode(3).count.println

for example (where the body desugars as println(count(encode(s,3)))). An advantage of the dot notation as syntactic sugar for function calls is that it is easy to extend the ‘primitive’ methods of any data type: just write a new function that takes that type as its first argument. In most object-oriented languages one would need to add that method to the class definition itself which is not always possible if such class came as a library for example.

 The Koka Programming Language