#!/usr/bin/rebol
REBOL [
    Title: "A First Rot13 in REBOL"
    Author: "Teknovore <tek@wiw.org>"
    Date: 4-Oct-1998
]

lowtable: "anbocpdqerfsgthuivjwkxlymznaobpcqdresftguhviwjxkylzm"
uptable: "ANBOCPDQERFSGTHUIVJWKXLYMZNAOBPCQDRESFTGUHVIWJXKYLZM"

while [
    string: input
    not empty? string
] [
    while [not empty? string] [
	char: make char! string
    	string: next string
        if not none? find/case lowtable char [
	    foo: length? lowtable
            foo: foo - length? do [find/case lowtable char]
   	    if foo // 2 <> 0 [
	        foo: length? lowtable
	        foo: foo - length? do [find/case next
		    do [find/case lowtable char] char]
	    ]
            char: pick lowtable foo + 2
	] else [ if not none? find/case uptable char [
	    foo: length? uptable
            foo: foo - length? do [find/case uptable char]
   	    if foo // 2 <> 0 [
	        foo: length? uptable
	        foo: foo - length? do [find/case next
		    do [find/case uptable char] char]
	    ]
            char: pick uptable foo + 2
	] ]
	prin char
    ]
]
quit