Bug fix and docs in wrap

basis/wrap/authors.txt

@@ -1 +1,2 @@
 Daniel Ehrenberg
+Slava Pestov

basis/wrap/wrap-docs.factor

@@ -0,0 +1,41 @@
+! Copyright (C) 2009 Daniel Ehrenberg
+! See http://factorcode.org/license.txt for BSD license.
+USING: help.syntax help.markup strings math kernel ;
+IN: wrap
+
+ABOUT: "wrap"
+
+ARTICLE: "wrap" "Word wrapping"
+"The " { $vocab-link "wrap" } " vocabulary implements word wrapping. There is support for simple string wrapping, with the following words:"
+{ $subsection wrap-lines }
+{ $subsection wrap-string }
+{ $subsection wrap-indented-string }
+"Additionally, the vocabulary provides capabilities to wrap arbitrary groups of things, in units called words."
+{ $subsection wrap }
+{ $subsection word }
+{ $subsection <word> } ;
+
+HELP: wrap-lines
+{ $values { "lines" string } { "width" integer } { "newlines" "sequence of strings" } }
+{ $description "Given a string, divides it into a sequence of lines where each line has no more than " { $snippet "width" } " characters, unless there is a word longer than " { $snippet "width" } ". Linear whitespace between words is converted to a single space." } ;
+
+HELP: wrap-string
+{ $values { "string" string } { "width" integer } { "newstring" string } }
+{ $description "Given a string, alters the whitespace in the string so that each line has no more than " { $snippet "width" } " characters, unless there is a word longer than " { $snippet "width" } ". Linear whitespace between words is converted to a single space." } ;
+
+HELP: wrap-indented-string
+{ $values { "string" string } { "width" integer } { "indent" string } { "newstring" string } }
+{ $description "Given a string, alters the whitespace in the string so that each line has no more than " { $snippet "width" } " characters, unless there is a word longer than " { $snippet "width" } ". Linear whitespace between words is converted to a single space. Before each line, the indent string is added." } ;
+
+HELP: wrap
+{ $values { "words" { "a sequence of " { $instance word } "s" } } { "width" integer } { "lines" "a sequence of sequences of words" } }
+{ $description "Divides the words into lines, where the sum of the lengths of the words on a line (not counting breaks at the end of the line) is at most the given width. Every line except for the first one starts with a non-break, and every one but the last ends with a break." } ;
+
+HELP: word
+{ $class-description "A word, for the purposes of " { $vocab-link "wrap" } ", is a Factor object annotated with a length (in the " { $snippet "width" } " slot) and knowledge about whether it is an allowable position for an optional line break (in the " { $snippet "break?" } " slot). Words can be created with " { $link <word> } "." }
+{ $see-also wrap } ;
+
+HELP: <word>
+{ $values { "key" object } { "width" integer } { "break?" { { $link t } " or " { $link POSTPONE: f } } } { "word" word } }
+{ $description "Creates a " { $link word } " object with the given parameters." }
+{ $see-also wrap } ;

basis/wrap/wrap-tests.factor

@@ -1,5 +1,7 @@
-IN: wrap.tests
+! Copyright (C) 2008, 2009 Daniel Ehrenberg, Slava Pestov
+! See http://factorcode.org/license.txt for BSD license.
 USING: tools.test wrap multiline sequences ;
+IN: wrap.tests
     
 [
     {
@@ -23,6 +25,32 @@ USING: tools.test wrap multiline sequences ;
     } 35 wrap [ { } like ] map
 ] unit-test
 
+[
+    {
+        {
+            T{ word f 1 10 f }
+            T{ word f 2 10 f }
+            T{ word f 3 9 t }
+            T{ word f 3 9 t }
+            T{ word f 3 9 t }
+        }
+        {
+            T{ word f 4 10 f }
+            T{ word f 5 10 f }
+        }
+    }
+] [
+    {
+        T{ word f 1 10 f }
+        T{ word f 2 10 f }
+        T{ word f 3 9 t }
+        T{ word f 3 9 t }
+        T{ word f 3 9 t }
+        T{ word f 4 10 f }
+        T{ word f 5 10 f }
+    } 35 wrap [ { } like ] map
+] unit-test
+
 [
     <" This is a
 long piece
@@ -46,3 +74,9 @@ word wrap.">
     <" This is a long piece of text that we wish to word wrap."> 12
     "  " wrap-indented-string
 ] unit-test
+
+[ "this text\nhas lots of\nspaces" ]
+[ "this text        has lots of       spaces" 12 wrap-string ] unit-test
+
+[ "hello\nhow\nare\nyou\ntoday?" ]
+[ "hello how are you today?" 3 wrap-string ] unit-test

basis/wrap/wrap.factor

@@ -1,3 +1,5 @@
+! Copyright (C) 2008, 2009 Daniel Ehrenberg, Slava Pestov
+! See http://factorcode.org/license.txt for BSD license.
 USING: sequences kernel namespaces make splitting
 math math.order fry assocs accessors ;
 IN: wrap
@@ -15,12 +17,25 @@ SYMBOL: width
 : break-here? ( column word -- ? )
     break?>> not [ width get > ] [ drop f ] if ;
 
+: walk ( n words -- n )
+    ! If on a break, take the rest of the breaks
+    ! If not on a break, go back until you hit a break
+    2dup bounds-check? [
+        2dup nth break?>>
+        [ [ break?>> not ] find-from drop ]
+        [ [ break?>> ] find-last-from drop 1+ ] if
+   ] [ drop ] if ;
+
 : find-optimal-break ( words -- n )
-    [ 0 ] dip [ [ width>> + dup ] keep break-here? ] find drop nip ;
+    [ 0 ] keep
+    [ [ width>> + dup ] keep break-here? ] find drop nip
+    [ 1 max swap walk ] [ drop f ] if* ;
 
 : (wrap) ( words -- )
-    dup find-optimal-break
-    [ 1 max cut-slice [ , ] [ (wrap) ] bi* ] [ , ] if* ;
+    [
+        dup find-optimal-break
+        [ cut-slice [ , ] [ (wrap) ] bi* ] [ , ] if*
+    ] unless-empty ;
 
 : intersperse ( seq elt -- seq' )
     [ '[ _ , ] [ , ] interleave ] { } make ;
@@ -34,9 +49,7 @@ SYMBOL: width
 
 : join-words ( wrapped-lines -- lines )
     [
-        [ break?>> ]
-        [ trim-head-slice ]
-        [ trim-tail-slice ] bi
+        [ break?>> ] trim-slice
         [ key>> ] map concat
     ] map ;