The Uniform Function Call Syntax generalizes calling a function and calling a member function.

This relatively small feature has a big impact how you think about objects how you reference code.

You can call a procedure two equivalent ways, by passing all the arguments to it or by treating the first argument like you would for an object when calling its methods (dot notation). For example calling procName which take three parameters can be done like:

procName(a, b, c)

or

a.procName(b, c)

You can omit the parentheses when they are empty. For example when no parameters:

procName2()

or

procName2

Or when there is one parameter:

procName3(a)

or

a.procName3()

or

a.procName3

The first parameter can be any type, it is not restricted to objects and you can use variables or literals.

For an add procedure with two integer parameters you can call it shown below. The last line shows chaining by adding 1 + 2 + 3.

v1 = add(1, 2)
v2 = 1.add(2)
v3 = 1.add(2).add(3)

You can extend an object defined in another module by defining a procedure with the object as the first parameter.

newMethodName(obj, a, b, c)

And you call it like the other methods of the object:

obj.newMethodName(a, b, c)

When you omit the parentheses it appears like you are accessing a member variable. These are called object getters in some languages. For example:

“str”.len

The Nim tutorial talks about how to do “setters”.

* https://nim-lang.org/docs/tut2.html

See the wikipeadia page for more information.

* https://en.wikipedia.org/wiki/Uniform_Function_Call_Syntax