modernize extra/roman

extra/roman/roman.factor

@@ -1,26 +1,20 @@
 ! Copyright (C) 2007 Doug Coleman.
 ! See http://factorcode.org/license.txt for BSD license.
-
 USING: arrays assocs kernel math math.order math.vectors namespaces
 quotations sequences sequences.lib sequences.private strings unicode.case ;
 IN: roman
 
 <PRIVATE
-
 : roman-digits ( -- seq )
     { "m" "cm" "d" "cd" "c" "xc" "l" "xl" "x" "ix" "v" "iv" "i" } ;
 
 : roman-values ( -- seq )
     { 1000 900 500 400 100 90 50 40 10 9 5 4 1 } ;
 
-TUPLE: roman-range-error n ;
+ERROR: roman-range-error n ;
 
 : roman-range-check ( n -- )
-    dup 1 3999 between? [
-        drop
-    ] [
-        roman-range-error boa throw
-    ] if ;
+    dup 1 3999 between? [ drop ] [ roman-range-error ] if ;
 
 : roman<= ( ch1 ch2 -- ? )
     [ 1string roman-digits index ] bi@ >= ;
@@ -39,7 +33,6 @@ TUPLE: roman-range-error n ;
     ] [
         first2 swap -
     ] if ;
-
 PRIVATE>
 
 : >roman ( n -- str )
@@ -55,13 +48,11 @@ PRIVATE>
     ] map sum ;
 
 <PRIVATE
-
 : 2roman> ( str1 str2 -- m n )
     [ roman> ] bi@ ;
 
 : binary-roman-op ( str1 str2 quot -- str3 )
     >r 2roman> r> call >roman ; inline
-
 PRIVATE>
 
 : roman+ ( str1 str2 -- str3 )