fix(packages): Tests for bug #724

Updates to the justification alternates support. Closes #724.

examples/packages/gutenberg.sil

@@ -4,19 +4,21 @@
 \script[src=packages/color]%
 \script[src=packages/rules]%
 \define[command=lig-ll]{\color[color=red]{\unichar{U+F4F9}}}%
-\define[command=nolig-fi]{f{}i}
+\define[command=lig-Th]{\color[color=red]{\font[features=+dlig]{Th}}}%
+\define[command=nolig-fi]{\color[color=red]{f{}i}}
 \define[command=ll]{\alt{{ll}{\lig-ll}}}
 \define[command=fi]{\alt{{fi}{\nolig-fi}}}
+\define[command=Th]{\alt{{Th}{\lig-Th}}}
 \define[command=nil]{}
 \define[command=and]{\alt{{and}{&}}}
-\define[command=ospace]{\alt{{\nil}{\glue[width=0.16667em]}}}
+\define[command=ospace]{\alt{{\nil}{\color[color=red]{\hrule[height=0.01em,width=0.16667em]}}}}
 \font[family=EB Garamond,size=11pt]%
 
 \par
 It has to be added that of all Gutenberg’s 290 B42-types, there are many ligatures and abbreviations, while the number of single characters with varying widths is small. (See illustration here.) The use of ligatures and abbreviations was absolutely crucial for Gutenberg’s justification technique, which could not be realized by narrower types only.
 
 \medskip\noindent\hrule[width=115mm,height=0.25mm]\medskip\indent\par
 
-It has to be added that of a\ll Gutenberg’s 290 B42-types\ospace, there are many ligatures \and abbreviations\ospace, while the number of single characters with varying widths is sma\ll\ospace. (See i\ll{}ustration here\ospace.) The use of ligatures \and abbreviations was absolutely crucial for Gutenberg’s justi\fi{}cation technique\ospace, which could not be realized by narrower types only\ospace. 
+It has to be added that of all Gutenberg’s 290 B42-types\ospace, there are many ligatures \and abbreviations\ospace, while the number of single characters with varying widths is small\ospace. (See i\ll{}ustration here\ospace.) \Th{}e use of ligatures \and abbreviations was absolutely crucial for Gutenberg’s justi\fi{}cation technique\ospace, which could not be realized by narrower types only\ospace.
 
 \end{document}

packages/gutenberg.lua

@@ -9,6 +9,50 @@ SILE.registerCommand("alt", function (_, content)
     options=options,
     selected=1
     })
-  alt.width=nil
   SILE.typesetter.state.nodes[#SILE.typesetter.state.nodes+1] = alt
 end)
+
+local bidi = require("packages/bidi")
+SILE.registerCommand("process-jalt", function (_, content)
+  local pretty = require("pl.pretty")
+  -- Process normally
+  local saveTypesetter = SILE.typesetter
+  SILE.typesetter = SILE.defaultTypesetter {}
+  SILE.typesetter:init(saveTypesetter.frame)
+  SILE.process(content)
+  SILE.typesetter:shapeAllNodes(SILE.typesetter.state.nodes)
+  table.remove(SILE.typesetter.state.nodes,1)
+  table.remove(SILE.typesetter.state.nodes,1)
+  -- Do bidi
+  bidi.reorder(SILE.typesetter.state, SILE.typesetter)
+  local nodes1 = SILE.typesetter.state.nodes
+
+  -- Process with +JALT
+  SILE.typesetter = SILE.defaultTypesetter {}
+  SILE.typesetter:init(saveTypesetter.frame)
+  local nodes2
+  SILE.settings.temporarily(function ()
+    SILE.settings.set("font.features", "+jalt")
+    SILE.process(content)
+    SILE.typesetter:shapeAllNodes(SILE.typesetter.state.nodes)
+    table.remove(SILE.typesetter.state.nodes,1)
+    table.remove(SILE.typesetter.state.nodes,1)
+    bidi.reorder(SILE.typesetter.state, SILE.typesetter)
+    nodes2 = SILE.typesetter.state.nodes
+  end)
+
+  -- Check if lengths are different...
+  SILE.typesetter = saveTypesetter
+  for i = 1,#nodes1 do
+    if nodes1[i]:isGlue() or (nodes1[i].width == nodes2[i].width) then
+      SILE.typesetter:pushHorizontal(nodes1[i])
+    else
+     local alt = SILE.nodefactory.newAlternative({
+        options= { nodes1[i], nodes2[i] },
+        selected=1
+        })
+      alt.bidiDone = true
+      SILE.typesetter:pushHorizontal(alt)
+   end
+  end
+end)

tests/bug-724.expected

@@ -5,9 +5,20 @@ Mx 	368.0824
 My 	34.7638
 Set font 	Gentium Plus;30;400;;normal;;LTR
 T	69 69	(bb)
-Draw line	20.9764 65.7638 50.0000 5.0000
-Mx 	70.9764
+Draw line	20.9764 65.7638 330.0000 5.0000
+Mx 	350.9764
 My 	70.7638
 T	17	(.)
+Draw line	20.9764 101.7638 330.0000 5.0000
+Mx 	368.0824
+My 	106.7638
+T	69 69	(bb)
+Draw line	20.9764 137.7638 330.0000 5.0000
+My 	142.7638
+T	69 69	(bb)
+Draw line	20.9764 173.7638 50.0000 5.0000
+Mx 	70.9764
+My 	178.7638
+T	17	(.)
 End page
 Finish

tests/bug-724.sil

@@ -8,7 +8,8 @@
 \nofolios%
 \nohyphenation\noindent%
 \font[size=30pt]%
-\hrule[width=330pt,height=5pt] \alt{a}{bb} \hrule[width=50pt,height=5pt].
+\hrule[width=330pt,height=5pt] \alt{a}{bb} \hrule[width=330pt,height=5pt].
 
+\noindent\hrule[width=330pt,height=5pt] {\alt{a}{bb}} \hrule[width=330pt,height=5pt] \alt{a}{bb} \hrule[width=50pt,height=5pt].
 
 \end{document}