Add pidigits benchmark from language shootout

extra/benchmark/pidigits/authors.txt

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+Aaron Schaefer

extra/benchmark/pidigits/pidigits.factor

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+! Copyright (c) 2009 Aaron Schaefer. All rights reserved.
+! The contents of this file are licensed under the Simplified BSD License
+! A copy of the license is available at http://factorcode.org/license.txt
+USING: arrays formatting fry grouping io kernel locals math math.functions
+    math.matrices math.parser math.primes.factors math.vectors prettyprint
+    sequences sequences.deep sets ;
+IN: benchmark.pidigits
+
+: extract ( z x -- n )
+    1 2array '[ _ v* sum ] map first2 /i ;
+
+: next ( z -- n )
+    3 extract ;
+
+: safe? ( z n -- ? )
+    [ 4 extract ] dip = ;
+
+: >matrix ( q s r t -- z )
+    4array 2 group ;
+
+: produce ( z n -- z' )
+    [ 10 ] dip -10 * 0 1 >matrix swap m. ;
+
+: gen-x ( x -- matrix )
+    dup 2 * 1 + [ 2 * 0 ] keep >matrix ;
+
+: consume ( z k -- z' )
+    gen-x m. ;
+
+:: (padded-total) ( row col -- str n format )
+    "" row col + "%" "s\t:%d\n"
+    10 col - number>string glue ;
+
+: padded-total ( row col -- )
+    (padded-total) '[ _ printf ] call( str n -- ) ;
+
+:: (pidigits) ( k z n row col -- )
+    n 0 > [
+        z next :> y
+        z y safe? [
+            col 10 = [
+                row 10 + y "\t:%d\n%d" printf
+                k z y produce n 1 - row 10 + 1 (pidigits)
+            ] [
+                y number>string write
+                k z y produce n 1 - row col 1 + (pidigits)
+            ] if
+        ] [
+            k 1 + z k consume n row col (pidigits)
+        ] if
+    ] [ row col padded-total ] if ;
+
+: pidigits ( n -- )
+    [ 1 { { 1 0 } { 0 1 } } ] dip 0 0 (pidigits) ;
+
+: pidigits-main ( -- )
+    10000 pidigits ;
+
+MAIN: pidigits-main