feat(filters): Add filter to fix title-casing of headings

Makefile.am

@@ -75,7 +75,7 @@ fontsdir = $(datadir)/fonts
 dist_fonts_DATA = fonts/Almendra-Bold.otf fonts/Almendra-BoldItalic.otf fonts/Almendra-Italic.otf fonts/Almendra-Regular.otf fonts/AlmendraDisplay-Regular.otf fonts/AlmendraSC-Bold.otf fonts/AlmendraSC-BoldItalic.otf fonts/AlmendraSC-Italic.otf fonts/AlmendraSC-Regular.otf fonts/FeFlow2.otf fonts/NexaRustExtras-Free.otf fonts/NexaRustHandmade-Extended-Free.otf fonts/NexaRustSans-Black-Free.otf fonts/NexaRustScriptL-0-Free.otf fonts/NexaRustSlab-BlackShadow01-Free.otf fonts/Nymphette.ttf fonts/PrintersOrnamentsOne.ttf
 
 filtersdir = $(datadir)/pandoc-filters
-dist_filters_DATA = pandoc-filters/chapterid.lua pandoc-filters/epubclean.lua pandoc-filters/strip_for_mdbook.lua pandoc-filters/svg2pdf.py pandoc-filters/withoutfootnotes.lua pandoc-filters/withoutheadinglinks.lua pandoc-filters/withoutlinks.lua pandoc-filters/withverses.lua
+dist_filters_DATA = pandoc-filters/chapterid.lua pandoc-filters/epubclean.lua pandoc-filters/strip_for_mdbook.lua pandoc-filters/titlecase_titles.lua pandoc-filters/svg2pdf.py pandoc-filters/withoutfootnotes.lua pandoc-filters/withoutheadinglinks.lua pandoc-filters/withoutlinks.lua pandoc-filters/withverses.lua
 
 classesdir = $(datadir)/classes
 dist_classes_DATA = classes/cabook.lua classes/cabinding.lua classes/cageometry.lua

configure.ac

@@ -95,6 +95,7 @@ AM_COND_IF([DEPENDENCY_CHECKS], [
     AX_PROGVAR([bc])
     AX_PROGVAR([curl])
     AX_PROGVAR([cut])
+    AX_PROGVAR([decasify])
     AX_PROGVAR([deepl])
     AX_PROGVAR([diff])
     AX_PROGVAR([entr])
@@ -145,6 +146,7 @@ AM_COND_IF([DEPENDENCY_CHECKS], [
     ])
 
     AX_PROG_LUA(5.1, [], [], AC_MSG_ERROR([lua interpreter is required]))
+    AX_LUAROCKS_ROCK(decasify)
     AX_LUAROCKS_ROCK(yaml)
 
     AC_PATH_PROG([PERL], [perl])

hooks/build

@@ -5,11 +5,11 @@ set -e
 
 REVISION=$(git describe --long --tags | sed 's/^v//;s/\([^-]*-g\)/r\1/;s/-/./g')
 
-RUNTIME_DEPS='bc bcprov curl entr epubcheck fontconfig ghostscript git git-warp-time imagemagick inetutils'\
+RUNTIME_DEPS='bc bcprov curl decasify entr epubcheck fontconfig ghostscript git git-warp-time imagemagick inetutils'\
 ' inkscape java-commons-lang jq kindlegen libertinus-font libgit2 m4 make mdbook moreutils nodejs'\
 ' pandoc-sile-git pcre pdftk podofo-tools poppler povray sassc sile sqlite'\
 ' tex-gyre-fonts texlive ttf-hack yq zint zola zsh'\
-' lua luarocks lua-colors-git lua-filesystem lua-yaml'\
+' lua luarocks lua-decasify lua-colors-git lua-filesystem lua-yaml'\
 ' perl perl-yaml perl-yaml-merge-simple'\
 ' python python-isbnlib python-deepl python-pandocfilters python-pantable python-ruamel-yaml python-usfm2osis-cw-git'\
 ' xcftools xorg-server-xvfb'

pandoc-filters/titlecase_titles.lua

@@ -0,0 +1,16 @@
+-- Convert all headings to title case following document language rules
+
+local decasify = require("decasify")
+local locale = os.getenv("LANGUAGE") or "en"
+
+Pandoc = function (doc)
+  local language = pandoc.utils.stringify(doc.meta.language or locale)
+  return doc:walk {
+    Header = function (element)
+      local title = pandoc.utils.stringify(element.content)
+      local cased = decasify.titlecase(title, language)
+      element.content = cased
+      return element
+    end
+  }
+end

rules/casile.mk.in

@@ -45,11 +45,12 @@ _ENV := _WRAPTARGET=false
 # with paths of their own.
 AWK ?= @AWK@
 BC ?= @BC@
-DIFF ?= @DIFF@
 CMP ?= @CMP@
 CURL ?= @CURL@
 CUT ?= @CUT@
+DECASIFY ?= @DECASIFY@
 DEEPL ?= @DEEPL@
+DIFF ?= @DIFF@
 EGREP ?= @EGREP@
 ENTR ?= @ENTR@
 EPUBCHECK ?= @EPUBCHECK@

rules/utilities.mk

@@ -140,6 +140,7 @@ normalize_lua: $(LUASOURCES)
 	$(call munge,$^,$(SED) -e 's/function */function /g',Normalize Lua coding style)
 
 .PHONY: normalize_markdown
+normalize_markdown: private PANDOCFILTERS += --lua-filter=$(CASILEDIR)/pandoc-filters/titlecase_titles.lua
 normalize_markdown: $(MARKDOWNSOURCES)
 	$(call munge,$(filter %.md,$^),msword_escapes.pl,Fixup bad MS word typing habits that Pandoc tries to preserve)
 	$(call munge,$(filter %.md,$^),lazy_quotes.pl,Replace lazy double single quotes with real doubles)
@@ -170,6 +171,7 @@ split_chapters:
 	$(foreach SOURCE,$(MARKDOWNSOURCES),$(call split_chapters,$(SOURCE)))
 
 .PHONY: normalize_files
+normalize_files: private PANDOCFILTERS = --lua-filter=$(CASILEDIR)/pandoc-filters/titlecase_titles.lua
 normalize_files: private PANDOCFILTERS = --lua-filter=$(CASILEDIR)/pandoc-filters/chapterid.lua
 normalize_files:
 	$(GIT) diff-index --quiet --cached HEAD || exit 1 # die if anything already staged