# Hanoi Love

Implementation of programming language Hanoi Love

This interpreter is the reference implementation of Hanoi Love language, written by its author and released on April 30, 2001. It is written in QuickBASIC and distributed as its source code. The interpreter reads program text from provided file and prints the results to standard output.

## Examples:

### Hello, World!:

Example for versions Hanoi Love

This example is a translation of Brainfuck example. All stacks are empty, and all calculations are done in the register. Stack A is used as a source of constant 1: since it’s empty, pop operation on it returns 1. This way, ; and ` operations become “increment register by 1” and “decrement register by 1”, i.e., they are equivalent to `+` and `-` Brainfuck commands. `"'` pushes the contents of the register to standard out, i.e., is equivalent to `.` in Brainfuck.

``````;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; "'
;;;;;;;;;;;;;;;;;;;;;;;;;;;;; "'
;;;;;;; "'
"'
;;; "'
``````````````````````````````````````````````````````````````````` "'
```````````` "'
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; "'
;;;;;;;;;;;;;;;;;;;;;;;; "'
;;; "'
`````` "'
```````` "'
``````````````````````````````````````````````````````````````````` "'
``````

### Fibonacci numbers:

Example for versions Hanoi Love

This example uses iterative definition of Fibonacci numbers. Stack A is empty (used for popping 1 from it) and is used for temporary storages. Stack B holds printable characters (comma and space) and two last Fibonacci numbers. Stack C holds a 1 for each Fibonacci number to be printed (6 1’s to print 6 numbers). On each iteration one number is popped from C. If it is positive, top number f2 from stack B is popped, converted to ASCII character of the corresponding digit and printed. After this number f1 is popped from stack B and added to f2. Finally, numbers f2 and f1+f2 are pushed back in stack B. A low-level description of the example is given in the comments.

Hanoi Love interpreter uses byte variables to store values of memory cells, so a maximum of 13 Fibonacci numbers can be printed. However, printing multi-digit numbers in Hanoi Love is rather similar to Brainfuck, so only first six single-digit numbers are printed.

``````;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; .'                   B (space) regr = ASCII for space
...;;;;;;;;;;;;.'                                     B (space comma) reg = ASCII for comma
...,                                                  A (empty) reg = 1
..''''''                                              C (6 ones for 6 numbers to print) reg = 1
..`.'...;.'                                           B (space comma 0 1) reg = 1
.,                                                    C (pop number to reg) reg = 1
.'...                                                 D (remembered this place)
:                                                     if this number is positive print top number in B and move to next Fibonacci number
...,                                                  B (space comma f1) reg = f2
.'                                                    C (f2) reg = f2
..;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; "' A (empty) reg = f2 in ASCII (printed)
.,                                                    B (space comma) reg = f1
.'                                                    C (f2 f1) reg = f2
..., "'                                               B (space) reg = comma (printed)
.'                                                    C (f2 f1 comma) reg = comma
..., "' '                                             B (space) reg = space (printed)
.,...'                                                B (space comma) reg = comma
.,                                                    C (f2) reg = f1
..'                                                   A (f1) reg = f1
..,                                                   C (empty) reg = f2
...'                                                  B (space comma f2) reg = f2
...;                                                  A (empty) reg = f1+f2
.'                                                    B (space comma f2 f1+f2)
.,                                                    C (pop number to reg)
.,                                                    D (get previous command location)
!
...,,,...;; "' "' "'                                  pop everything from B and convert comma to point (printed three times)
``````