RC LANG

Syntax

// sugared fib is below
fib n
  let one = 1
  if n == 0
    then
      one
    else
      if n == 1
        then
          one
        else
          fib(n-1) + fib(n-2)

// desugared fib is below  
// { } -> contain blocks and blocks are thunks so they can be functions too.
// Blocks are special functions called thunk that evaluate to a value and then remember it.
// On further invocation, blocks just return the value instead of executing their fn body
// arguments is what the runtime gives to fib when fib is called
fib arguments {
  let n = arguments[0]
  let one = 1
  let cond1 = n == 0
  
  // if is a function that has the following arguments:
  // if condition thenBlock elseBlock
  
  if cond1 { one } {  //elseBlock
                      let cond2 = n == 1
                      if cond2 { one } {  //elseBlock
                                          let arg1 = n - 1
                                          let arg2 = n - 2
                                          let result1 = fib arg1
                                          let result2 = fib arg2
                                          result1 + result2
                                        }
                    }
  // functions can only take value not an expression which is why fib(n-1) + fib(n-2) is desugared as lines 15-19
  // + is a function that takes two values, so we desugar to get those values before calling +
}