From 5c7e482d0234e6692cb685cccd78b664f1790322 Mon Sep 17 00:00:00 2001
From: Martin Mares <mj@ucw.cz>
Date: Tue, 5 Jun 2018 22:09:07 +0200
Subject: [PATCH] ucw-link: Better macros for URLs and URL links

---
 test-ref.tex |  4 +++-
 ucw-link.tex | 29 ++++++++++++++++++++++++-----
 2 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/test-ref.tex b/test-ref.tex
index 13f9e1c..95915ab 100644
--- a/test-ref.tex
+++ b/test-ref.tex
@@ -27,7 +27,9 @@
 
 \chapter[sec]{Caput secunda}
 
-\url{http://pruvodce.ucw.cz/errata.html}
+\url{http://pruvodce.ucw.cz/errata%21.html}
+
+\linkurl{http://pruvodce.ucw.cz/}{See the web page.}
 
 \chapter[ter]{Caput tertia}
 
diff --git a/ucw-link.tex b/ucw-link.tex
index 58f498f..ef89593 100644
--- a/ucw-link.tex
+++ b/ucw-link.tex
@@ -37,15 +37,34 @@
 \def\linkpage#1#2{\ifclickable\pdfstartlink\commonlinkargs goto page #1 {/Fit}\relax #2\pdfendlink\else #2\fi}
 
 % Typeset a clickable URL
-% Currently, all weird characters must be properly escaped.
-\def\url#1{%
+% \url{http://example.com/}
+\def\url{\begingroup\allowurlchars\urlaux}
+\def\urlaux#1{\linkurlaux{#1}{\displayurl #1^^X}}
+
+% Typeset a clickable link to the given URL
+% \linkurl{http://example.com/}{text}
+\def\linkurl{\begingroup\allowurlchars\linkurlaux}
+\def\linkurlaux#1#2{\endgroup
 	\leavevmode
 	\ifclickable
 		\pdfstartlink\commonlinkargs user {/Subtype/Link /A << /Type/Action /S/URI /URI(#1) >>}\relax
 	\fi
-	\xurl #1^^X%
+	#2%
 	\ifclickable
-		\pdfendlink\relax
+		\pdfendlink
 	\fi
 }
-\def\xurl#1:#2#3^^X{{\I #1:#2\ifx#2/\kern-0.1em\fi#3}}
+
+% Catcode each special character valid in URL to 'other'
+\def\allowurlchars{\catcode`\#=12\catcode`\_=12\catcode`\%=12\catcode`\&=12\catcode`\$=12\catcode`\~=12\relax}
+
+% Style switches and the beginning/end of an URL
+\let\urlprefix\it
+\let\urlsuffix\/
+
+% Kern to place between "//" in an URL
+\newdimen\urlinterslashkern
+\urlinterslashkern=-0.1em
+
+% Internal macro for typesetting of URLs
+\def\displayurl#1:#2#3^^X{{\urlprefix #1:#2\ifx#2/\kern\urlinterslashkern\fi#3\urlsuffix}}
-- 
2.39.2