Fixing missing unicode characters in rendered PDF (#177)

* Tweaking fonts to support unicode characters + making it pretty

* Adding unicode mapping to math symbols for missing characters

* Trying older ghc to fix the CI build issues

Makefile

@@ -6,6 +6,8 @@ HTEMPLATE = resources/page.tmpl
 LTEMPLATE = resources/page.latex
 ETEMPLATE = resources/page.epubt
 
+UNICODE_MAP = resources/unicodemapping.tex
+
 FLAGS = --standalone --toc --toc-depth=2 --highlight-style pygments
 LFLAGS = --top-level-division=chapter -V documentclass=book
 HFLAGS = -c css/style.css -c css/layout.css
@@ -33,7 +35,7 @@ includes: includes.hs
 	| $(PANDOC) -f $(IFORMAT) -t epub $(FLAGS) $(EFLAGS) -o $@
 
 %.pdf: %.md includes
-	./includes < $< | $(PANDOC) -c -s -f $(IFORMAT) --template $(LTEMPLATE) --pdf-engine=xelatex $(FLAGS) $(LFLAGS) -o $@
+	./includes < $< | $(PANDOC) -c -s -f $(IFORMAT) --template $(LTEMPLATE) --include-in-header $(UNICODE_MAP) --pdf-engine=xelatex $(FLAGS) $(LFLAGS) -o $@
 
 clean:
 	-rm -f $(CHAPTERS) $(HTML) $(PDF) $(EPUB)

resources/page.latex

@@ -11,7 +11,6 @@ $if(linestretch)$
 $endif$
 \usepackage{amssymb,amsmath}
 \usepackage{ifxetex,ifluatex}
-\usepackage{fixltx2e} % provides \textsubscript
 \ifnum 0\ifxetex 1\fi\ifluatex 1\fi=0 % if pdftex
   \usepackage[$if(fontenc)$$fontenc$$else$T1$endif$]{fontenc}
   \usepackage[utf8]{inputenc}
@@ -25,6 +24,7 @@ $endif$
     \usepackage{fontspec}
   \fi
   \defaultfontfeatures{Ligatures=TeX,Scale=MatchLowercase}
+  \setmonofont{DejaVu Sans Mono}
 $if(euro)$
   \newcommand{\euro}{€}
 $endif$

resources/unicodemapping.tex

@@ -0,0 +1,14 @@
+\newcommand{\sbullet}{%
+  \texorpdfstring{\textsbullet}{\textbullet}%
+}
+\DeclareRobustCommand{\textsbullet}{%
+  \unskip~\,\begin{picture}(1,1)(0,-3)\circle*{3}\end{picture}\ %
+}
+\usepackage{newunicodechar}
+\newunicodechar{⊥}{\ensuremath{\bot}}
+\newunicodechar{⊤}{\ensuremath{\top}}
+\newunicodechar{∨}{\ensuremath{\vee}}
+\newunicodechar{∧}{\ensuremath{\wedge}}
+\newunicodechar{⇒}{\ensuremath{\Rightarrow}}
+\newunicodechar{•}{\ensuremath{\sbullet}}
+\newunicodechar{λ}{\ensuremath{\lambda}}

shell.nix

@@ -1,18 +1,22 @@
-{ nixpkgs ? <nixpkgs>, compiler ? "ghc843" }:
+{ pkgs ? import <nixpkgs> {}, compiler ? "ghc843" }: with pkgs;
 let
-  pkgs = import nixpkgs { };
   ghcWithDeps = pkgs.haskell.packages.${compiler}.ghcWithPackages
     ( ps: with ps; [ base pandoc containers ] );
   tex = with pkgs; texlive.combine {
     inherit (texlive)
       scheme-small
       xetex
+      newunicodechar
       ;
   };
+  fontsConf = makeFontsConf {
+    fontDirectories = [ dejavu_fonts ];
+  };
 in
   pkgs.stdenv.mkDerivation {
     name = "wiwinwlh-env";
     buildInputs = [ ghcWithDeps tex ];
+    FONTCONFIG_FILE = fontsConf;
     shellHook = ''
       export LANG=en_US.UTF-8
       eval $(egrep ^export ${ghcWithDeps}/bin/ghc)