--- a/slides/slides04.tex	Thu Apr 16 19:15:46 2020 +0100
+++ b/slides/slides04.tex	Wed May 06 15:37:31 2020 +0100
@@ -9,6 +9,12 @@
 
 \pgfplotsset{compat=1.11}
 
+
+% a hand written lexer for SML
+% https://ponyo.org/
+% https://github.com/eatonphil/ponyo/blob/master/src/Sml/Lexer.sml
+
+
 \newcommand{\bl}[1]{\textcolor{blue}{#1}}  
 
 \renewcommand{\slidecaption}{CFL 04, King's College London}