a little bit of cleanup, trying to get rid of some stack shuffling

extra/suffix-arrays/suffix-arrays-docs.factor

@@ -1,7 +1,7 @@
 ! Copyright (C) 2008 Marc Fauconneau.
 ! See http://factorcode.org/license.txt for BSD license.
 USING: arrays help.markup help.syntax io.streams.string
-sequences strings math ;
+sequences strings math suffix-arrays.private ;
 IN: suffix-arrays
 
 HELP: >suffix-array
@@ -32,7 +32,7 @@ HELP: query
 { $description "Returns " } ;
 
 ARTICLE: "suffix-arrays" "Suffix arrays"
-"The " { $vocab-link "suffix-arrays" } " vocabulary implements the suffix array data structure for efficient lookup of subsequences." $nl
+"The " { $vocab-link "suffix-arrays" } " vocabulary implements the suffix array data structure for efficient lookup of subsequences. This suffix array implementation is a sorted array of suffixes. Querying it for matches uses binary search for efficiency." $nl
 
 "Creating new suffix arrays:"
 { $subsection >suffix-array }

extra/suffix-arrays/suffix-arrays-tests.factor

@@ -1,27 +1,30 @@
 ! Copyright (C) 2008 Marc Fauconneau.
 ! See http://factorcode.org/license.txt for BSD license.
-USING: tools.test suffix-arrays kernel namespaces ;
+USING: tools.test suffix-arrays kernel namespaces sequences ;
 IN: suffix-arrays.tests
 
 ! built from [ all-words 10 head [ name>> ] map ]
-{
+[ ] [
-    "run-tests"
+     SA{
-    "must-fail-with"
+        "run-tests"
-    "test-all"
+        "must-fail-with"
-    "short-effect"
+        "test-all"
-    "failure"
+        "short-effect"
-    "test"
+        "failure"
-    "<failure>"
+        "test"
-    "this-test"
+        "<failure>"
-    "(unit-test)"
+        "this-test"
-    "unit-test"
+        "(unit-test)"
-} "strings" set
+        "unit-test"
+    } "suffix-array" set
+] unit-test
 
-[ "strings" get >suffix-array "" swap query ] must-fail
+[ "suffix-array" get "" swap query ] must-fail
 
-[ { } >suffix-array "something" swap query ] must-fail
+[ SA{ } "something" swap query ] must-fail
 
 [ V{ "unit-test" "(unit-test)" } ]
-[ "strings" get >suffix-array "unit-test" swap query ] unit-test
+[ "suffix-array" get "unit-test" swap query ] unit-test
 
-[ V{ } ] [ "strings" get >suffix-array "something else" swap query ] unit-test
+[ t ]
+[ "suffix-array" get "something else" swap query empty? ] unit-test

extra/suffix-arrays/suffix-arrays.factor

@@ -4,28 +4,27 @@ USING: parser kernel arrays math accessors sequences
 math.vectors math.order sorting binary-search sets assocs fry ;
 IN: suffix-arrays
 
-! this suffix array is a sorted array of suffixes
+<PRIVATE
-! query is efficient through binary searches
-
 : suffixes ( string -- suffixes-seq )
     dup length [ tail-slice ] with map ;
 
+: prefix<=> ( begin seq -- <=> )
+    [ <=> ] [ swap head? ] 2bi [ drop +eq+ ] when ;
+ 
+: find-index ( begin suffix-array -- index )
+    [ prefix<=> ] with search drop ;
+
+: from-to ( index begin suffix-array -- from to )
+    swap '[ _ head? not ]
+    [ find-last-from drop 1+ ]
+    [ find-from drop ] 3bi ;
+PRIVATE>
+
 : >suffix-array ( seq -- array )
     [ suffixes ] map concat natural-sort ;
 
 : SA{ \ } [ >suffix-array ] parse-literal ; parsing
 
-: prefix<=> ( seq begin -- <=> )
-    [ swap <=> ] [ head? ] 2bi [ drop +eq+ ] when ;
- 
-: find-index ( suffix-array begin -- index )
-    '[ _ prefix<=> ] search drop ;
-
-: from-to ( index suffix-array begin -- from to )
-    '[ _ head? not ]
-    [ find-last-from drop 1+ ]
-    [ find-from drop ] 3bi ;
-
 : query ( begin suffix-array -- matches )
-    [ swap [ find-index ] 2keep from-to [ min ] keep ] keep
+    [ [ find-index ] 2keep from-to [ min ] keep ] keep
     <slice> [ seq>> ] map prune ;