"The " { $vocab-link "wrap" } " vocabulary implements word wrapping. Wrapping can take place based on simple strings, assumed to be monospace, or abstract word objects."
{ $vocab-subsection "String word wrapping" "wrap.strings" }
{ $vocab-subsection "Word object wrapping" "wrap.words" } ;
+
+HELP: element
+{ $class-description "An element to be wrapped. It has the following slots:" }
+{ $table
+ { { $slot "contents" } "The object being wrapped." }
+ { { $slot "black" } "The width of the object (e.g., the text length)." }
+ { { $slot "white" } "The space after the object (e.g., trailing whitespace)." }
+} ;
+
+HELP: wrap
+{ $values { "elements" { $sequence element } } { "width" real } }
+{ $description "Break the " { $snippet "elements" } " into lines such that the total width of each line tries to be less than " { $snippet "width" } " while attempting to minimize the raggedness represented by the amount of space at the end of each line. Returns an array of lines." } ;
! Copyright (C) 2009 Daniel Ehrenberg
+! Copyright (C) 2017 John Benediktsson
! See http://factorcode.org/license.txt for BSD license.
-USING: accessors arrays combinators combinators.short-circuit
-fry kernel kernel.private lists locals math sequences typed ;
+USING: accessors arrays kernel locals math sequences
+sequences.private ;
IN: wrap
-! black is the text length, white is the whitespace length
TUPLE: element contents black white ;
-C: <element> element
-
-<PRIVATE
-
-: element-length ( element -- n )
- [ black>> ] [ white>> ] bi + ; inline
-
-TUPLE: paragraph line-max lines head-width tail-cost ;
-C: <paragraph> paragraph
-
-: if-one-line ( paragraph true false -- )
- [ dup lines>> 1list? ] 2dip if ; inline
-
-TYPED: top-fits? ( paragraph: paragraph -- ? )
- [ head-width>> ] [ line-max>> ] bi <= ; inline
-
-TYPED: fits? ( paragraph: paragraph -- ? )
- ! Make this not count spaces at end
- { [ lines>> car 1list? ] [ top-fits? ] } 1|| ; inline
-
-TYPED: paragraph-cost ( paragraph: paragraph -- cost )
- [ drop 0 ] [
- [ head-width>> ] [ line-max>> - sq ] [ tail-cost>> ] tri +
- ] if-one-line ; inline
-: min-cost ( paragraphs -- paragraph )
- [ paragraph-cost ] infimum-by ; inline
-
-TYPED: new-line ( paragraph: paragraph element: element -- paragraph )
- {
- [ drop line-max>> ]
- [ [ lines>> ] [ 1list ] bi* swons ]
- [ nip black>> ]
- [ drop paragraph-cost ]
- } 2cleave <paragraph> ; inline
-
-TYPED: add-element ( paragraph: paragraph element: element -- )
- [ '[ _ element-length + ] change-head-width ]
- [ '[ unswons _ swons swons ] change-lines ] bi drop ; inline
-
-TYPED: wrap-step ( paragraphs: array element: element -- paragraphs )
- [ [ min-cost ] dip new-line ]
- [ dupd '[ _ add-element ] each ]
- 2bi swap prefix { array } declare
- [ fits? ] filter ; inline
-
-: 1paragraph ( line-max element -- paragraph )
- [ 1list 1list ] [ black>> ] bi 0 <paragraph> ;
-
-: post-process ( paragraph -- array )
- lines>> [ [ contents>> ] lmap>array ] lmap>array ;
-
-: initial-step ( line-max elements -- elements paragraph )
- reverse unclip swapd 1paragraph 1array ;
-
-PRIVATE>
+C: <element> element
-: wrap ( elements width -- array )
- swap [ drop { } ] [
- initial-step
- [ wrap-step ] reduce
- min-cost
- post-process
- ] if-empty ;
+:: wrap ( elements width -- array )
+ elements length integer>fixnum-strict :> #elements
+ elements [ black>> ] { } map-as :> black
+ elements [ white>> ] { } map-as :> white
+
+ #elements 1 + f <array> :> minima
+ #elements 1 + 0 <array> :> breaks
+
+ 0 0 minima set-nth-unsafe
+
+ minima [| base i |
+ 0 i 1 + [ dup #elements <= ] [| j |
+ j 1 - black nth-unsafe + dup :> w
+ j 1 - white nth-unsafe +
+
+ w width > [
+ j 1 - i = [
+ 0 j minima set-nth-unsafe
+ i j breaks set-nth-unsafe
+ ] when #elements
+ ] [
+ base
+ j #elements = [ width w - sq + ] unless :> cost
+ j minima nth-unsafe [ cost >= ] [ t ] if* [
+ cost j minima set-nth-unsafe
+ i j breaks set-nth-unsafe
+ ] when j
+ ] if 1 +
+ ] while 2drop
+ ] each-index
+
+ #elements [ dup 0 > ] [
+ [ breaks nth dup ] keep elements <slice>
+ [ contents>> ] map
+ ] produce nip reverse ;