EPUB: Populate acknowledgements.md with contributors

Use liquid-lua to generate acknowledgements_epub.md, which is used by
pandoc to build the EPUB book.  Also stop using the '{%-' / '-%}'
syntax, which liquid-lua does not support, in templates.

Also add a vertical space between the first bullet in each bulleted
list so pandoc recognizes bulleted lists as such. This has no effect on
the the website.

.gitignore

@@ -26,3 +26,7 @@ Gemfile.lock
 
 ## Emacs files
 auto/
+
+## Misc build files
+out/
+src/plfa/acknowledgements_epub.md

.travis.yml

@@ -22,6 +22,7 @@ addons:
     packages:
       - libgmp-dev
       - libicu-dev
+      - luarocks
 
 # Ensure we run BASH and not SH
 env:

Makefile

@@ -49,12 +49,10 @@ out/:
 #       sections are displayed to users. Some readers may be slow if the chapter
 #       files are too large, so for large documents with few level-1 headings, one
 #       might want to use a chapter level of 2 or 3."
-#
-#TODO: embedded fonts not working (path problem?)
 
 epub: out/plfa.epub
 
-out/plfa.epub: out/ $(AGDA) $(LUA) epub/main.css
+out/plfa.epub: out/ $(AGDA) $(LUA) epub/main.css src/plfa/acknowledgements_epub.md
 	pandoc --strip-comments \
 		--css=epub/main.css \
 		--epub-embed-font='assets/fonts/mononoki.woff' \
@@ -62,6 +60,7 @@ out/plfa.epub: out/ $(AGDA) $(LUA) epub/main.css
 		--epub-embed-font='assets/fonts/DejaVuSansMono.woff' \
 		--lua-filter epub/include-files.lua \
 		--lua-filter epub/rewrite-links.lua \
+		--lua-filter epub/rewrite-html-ul.lua \
 		--lua-filter epub/default-code-class.lua -M default-code-class=agda \
 		--standalone \
 		--fail-if-warnings \
@@ -70,7 +69,8 @@ out/plfa.epub: out/ $(AGDA) $(LUA) epub/main.css
 		-o "$@" \
 		epub/index.md
 
-
+src/plfa/acknowledgements_epub.md: src/plfa/acknowledgements.md _config.yml 
+	lua epub/run-liquid.lua _config.yml $< > $@
 
 
 # Convert literal Agda to Markdown
@@ -119,7 +119,7 @@ build-incremental: $(MARKDOWN)
 
 # Remove all auxiliary files
 clean:
-	rm -f .agda-stdlib.sed .links-*.sed
+	rm -f .agda-stdlib.sed .links-*.sed src/plfa/acknowledgements_epub.md
 ifneq ($(strip $(AGDAI)),)
 	rm $(AGDAI)
 endif
@@ -158,6 +158,9 @@ travis-setup:\
 	$(HOME)/agda-stdlib-$(AGDA_STDLIB_VERSION)/src\
 	$(HOME)/.agda/defaults\
 	$(HOME)/.agda/libraries\
+	$(HOME)/.local/share/lua/5.1/tinyyaml.lua\
+	$(HOME)/.local/share/lua/5.1/liquid.lua\
+	$(HOME)/.local/share/lua/5.1/cjson\
 	/usr/bin/pandoc
 
 .phony: travis-setup
@@ -204,6 +207,17 @@ $(HOME)/.local/bin/agda:
 	cd $(HOME)/agda-$(AGDA_VERSION);\
 		stack install --stack-yaml=stack-8.0.2.yaml
 
+$(HOME)/.local/share/lua/5.1/tinyyaml.lua:
+	luarocks install lua-tinyyaml
+
+$(HOME)/.local/share/lua/5.1/liquid.lua:
+	luarocks install liquid
+
+$(HOME)/.local/share/lua/5.1/cjson:
+	# Only this particular version works:
+	# https://github.com/mpx/lua-cjson/issues/56:
+	luarocks install lua-cjson 2.1.0-1
+
 travis-uninstall-agda:
 	rm -rf $(HOME)/agda-$(AGDA_VERSION)/
 	rm -f $(HOME)/.local/bin/agda

epub/index.md

@@ -65,7 +65,7 @@ src/plfa/part2/Substitution.lagda.md
 # Backmatter
 
 ``` {.include shift-heading-level-by=1}
-src/plfa/acknowledgements.md
+src/plfa/acknowledgements_epub.md
 src/plfa/Fonts.lagda.md
 src/plfa/statistics.md
 ```

epub/rewrite-html-ul.lua

@@ -0,0 +1,5 @@
+-- Transforms '<ul class={something}>' into '<ul>'.
+function RawBlock (el)
+    el.text = el.text:gsub('%s*<%s*ul%s*class=%s*"?[%w-]+"?%s*>%s*', '<ul>')
+    return el
+end

epub/run-liquid.lua

@@ -0,0 +1,19 @@
+local yaml = require 'tinyyaml'
+local liquid = require 'liquid'
+
+if #arg ~= 2 then
+    print('usage: ' .. arg[0] .. ' [yaml_file] [markdown_file]')
+    os.exit(1)
+end
+
+-- 1. Read YAML metadata from file, which we nest under the key 'site'.
+local metadata = { ['site'] = yaml.parse(io.open(arg[1]):read('a')) }
+
+-- 2. Read markdown document from file.
+local document = io.open(arg[2]):read('a')
+
+-- 3. Render the markdown document with the YAML metadata as context.
+local template = liquid.Template:parse(document)
+local result = template:render(liquid.InterpreterContext:new(metadata))
+
+print(result)

src/plfa/acknowledgements.md

@@ -7,12 +7,14 @@ next      : /Fonts/
 ---
 
 Thank you to:
+
 * The inventors of Agda, for a new playground.
 * The authors of Software Foundations, for inspiration.
 
 
 A special thank you, for inventing ideas on which
 this book is based, and for hand-holding:
+
 <ul class="list-of-contributors">
 <li>Andreas Abel</li>
 <li>Catarina Coquand</li>
@@ -25,31 +27,33 @@ this book is based, and for hand-holding:
 <li>Ulf Norell</li>
 </ul>
 
-{%- if site.contributors or site.extra_contributors -%}
+{% if site.contributors or site.extra_contributors %}
 For pull requests big and small, and for answering questions on the Agda mailing list:
+
 <ul class="list-of-contributors">
-{%- for contributor in site.contributors -%}
+{% for contributor in site.contributors %}
   <li><a href="https://github.com/{{ contributor.github_username }}">{{ contributor.name }}</a></li>
-{%- endfor -%}
-{%- for contributor in site.extra_contributors -%}
-  {%- if contributor.name and contributor.github_username -%}
+{% endfor %}
+{% for contributor in site.extra_contributors %}
+  {% if contributor.name and contributor.github_username %}
   <li><a href="https://github.com/{{ contributor.github_username }}">{{ contributor.name }}</a></li>
-  {%- else -%}
-  {%- if contributor.name -%}
+  {% else %}
+  {% if contributor.name %}
   <li>{{ contributor.name }}</li>
-  {%- endif -%}
-  {%- if contributor.github_username -%}
+  {% endif %}
+  {% if contributor.github_username %}
   <li><a href="https://github.com/{{ contributor.github_username }}">{{ contributor.github_username }}</a></li>
-  {%- endif -%}
-  {%- endif -%}
-{%- endfor -%}
+  {% endif %}
+  {% endif %}
+{% endfor %}
 <li>[Your name goes here]</li>
 </ul>
-{%- else -%}
-{%- endif -%}
+{% else %}
+{% endif %}
 
 
 For support:
+
 * EPSRC Programme Grant EP/K034413/1
 * NSF Grant No. 1814460
 * Foundation Sciences Mathematiques de Paris (FSMP)