contrib/porter-stemmer separated out from core

contrib/README.txt

@@ -38,6 +38,7 @@ Available libraries:
 - match -- pattern matching (Chris Double)
 - math -- extended math library (Doug Coleman, Slava Pestov)
 - parser-combinators -- Haskell-style parser combinators (Chris Double)
+- porter-stemmer -- Porter stemming algorithm (Slava Pestov)
 - postgresql -- PostgreSQL binding (Doug Coleman)
 - process -- Run external programs (Slava Pestov, Doug Coleman)
 - random-tester -- Random compiler tester (Doug Coleman)

contrib/all.factor

@@ -9,7 +9,8 @@ contrib/hardware-info contrib/hexdump contrib/http
 contrib/httpd contrib/http-client contrib/jedit
 contrib/jni contrib/json contrib/lambda contrib/lazy-lists
 contrib/lindenmayer contrib/match contrib/math
-contrib/parser-combinators contrib/postgresql contrib/process
+contrib/parser-combinators contrib/porter-stemmer
+contrib/postgresql contrib/process
 contrib/random-tester contrib/rss contrib/sequences
 contrib/serialize contrib/shuffle contrib/slate
 contrib/space-invaders contrib/splay-trees contrib/sqlite

contrib/porter-stemmer/load.factor

@@ -0,0 +1,4 @@
+PROVIDE: contrib/porter-stemmer
+{ +files+ { "porter-stemmer.factor" "porter-stemmer.facts" } }
+{ +tests+ { "test/porter-stemmer.factor" } }
+{ +help+ "porter-stemmer" } ;

contrib/porter-stemmer/porter-stemmer.facts

@@ -52,3 +52,21 @@ HELP: step5
 HELP: stem
 { $values { "str" "a string" } { "newstr" "a new string" } }
 { $description "Applies the Porter stemming algorithm to the input string." } ;
+
+ARTICLE: "porter-stemmer" "Porter stemming algorithm"
+"The help system uses the Porter stemming algorithm to normalize words when building the full-text search index."
+$terpri
+"The Factor implementation of the algorithm is based on the Common Lisp version, which was hand-translated from ANSI C by Steven M. Haflich. The original ANSI C was written by Martin Porter."
+$terpri
+"A detailed description of the algorithm, along with implementations in various languages, can be at in " { $url "http://www.tartarus.org/~martin/PorterStemmer" } "."
+$terpri
+"The main word of the algorithm takes an English word as input and outputs its stem:"
+{ $subsection stem }
+"The algorithm consists of a number of steps:"
+{ $subsection step1a }
+{ $subsection step1b }
+{ $subsection step1c }
+{ $subsection step2 }
+{ $subsection step3 }
+{ $subsection step4 }
+{ $subsection step5 } ;