--- a/handouts/ho01.tex	Thu Jul 30 13:50:54 2020 +0100
+++ b/handouts/ho01.tex	Sat Aug 15 14:18:37 2020 +0100
@@ -51,10 +51,10 @@
 write into code the machine can run as fast as possible. Developing a
 compiler is an old craft going back to 1952 with the first compiler
 written by Grace Hopper.\footnote{Who many years ago was invited on a
-talk show hosted by David Letterman, see
-\url{https://youtu.be/3N_ywhx6_K0?t=31}.} Why studying compilers
+talk show hosted by David Letterman.
+\here{https://youtu.be/3N_ywhx6_K0?t=31}.} Why studying compilers
 nowadays?  An interesting answer is given by John Regher in his compiler
-blog:\footnote{\url{http://blog.regehr.org/archives/1419}}
+blog:\here{http://blog.regehr.org/archives/1419}
 
 \begin{quote}\it{}``We can start off with a couple of observations
   about the role of compilers. First, hardware is getting weirder
@@ -107,7 +107,7 @@
 program (crashing it or making it go into an infinite loop, if not
 worse). This kind of ``inspecting'' mechanism is also implemented in
 popular network security tools such as Snort and
-Bro.\footnote{\url{www.snort.org}, \url{www.bro.org}} They scan incoming
+Bro.\here{www.snort.org}\here{www.bro.org} They scan incoming
 network traffic for computer viruses or malicious packets. Similarly
 filtering out spam usually involves looking for some signature
 (essentially a string pattern). The point is that the fast