arity.md

Arity and dispatch

• functions have a single, known arity

Given a function f, with arity 3 (lambda (a b c) ...), application can be performed in three ways:

partial application: (f 1)

• return curried function with arity 2

exact application: (f 1 2 3)

• invoke function call target with args

"over" application: (f 1 2 3 4 5)

• invoke function with 1 2 3
• expect return to be function
• invoke returned function with remaining arguments 4 5
• repeat until either partial or exact application

InvokeNode

Function f = (Function)this.functionNode.executeGeneric(frame)

while (arity of f is less than number of consumed arguments) {
  Object[] argumentValues = evaluate and consume arguments needed for function
  function = (Function) call(f, argumentValues)
}

if (arity of f is greater than number of arguments) {
  return curried version of f
} else {
  Object[] argumentValues = evaluate remaining, unconsumed arguments
  call(f, argumentValues)
}