From 0c237a9f7495940ef0e74778bde04962f652a02a Mon Sep 17 00:00:00 2001
From: Martin Mares <mj@ucw.cz>
Date: Tue, 5 Jun 2018 21:41:57 +0200
Subject: [PATCH] Separate modules for links and references

---
 test-ref.tex |  2 +-
 ucw-link.tex | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
 ucw-ref.tex  | 40 ++++------------------------------------
 3 files changed, 54 insertions(+), 37 deletions(-)
 create mode 100644 ucw-link.tex

diff --git a/test-ref.tex b/test-ref.tex
index 9967773..cefb5dc 100644
--- a/test-ref.tex
+++ b/test-ref.tex
@@ -33,6 +33,6 @@
 
 See also chapter~\chapref{pri} at page \ref{page}{pri}.
 
-Hard link to page~\pagelink{1}.
+Hard link to \linkpage{1}{page~1}.
 
 \bye
diff --git a/ucw-link.tex b/ucw-link.tex
new file mode 100644
index 0000000..cbe4ec9
--- /dev/null
+++ b/ucw-link.tex
@@ -0,0 +1,49 @@
+% The UCW Macro Collection: Destinations and links
+% Written by Martin Mares <mj@ucw.cz> in 2018 and placed into public domain
+% -------------------------------------------------------------------------
+
+% Should clickable links be produced?
+\newif\ifclickable
+\clickabletrue
+
+% Common style of all clickable links
+\pdflinkmargin=1pt
+\def\commonlinkargs{height \the\dimexpr\ht\strutbox-0.5pt\relax depth \the\dimexpr\dp\strutbox-0.5pt\relax attr {/C [0 0 0.5] /Border [0 0 2]}}
+
+% Define a PDF destination for the current position at the page
+\def\destpos#1{\ifclickable\pdfdest name {#1} xyz\relax\fi}
+
+% Define a PDF destination for the current page
+\def\destpage#1{\ifclickable\pdfdest name {#1} fit\relax\fi}
+
+% Typeset a clickable link to the given destination
+% \link{dest}{text}
+\def\link#1#2{%
+	\ifclickable
+		\pdfstartlink\commonlinkargs goto name {#1}\relax
+		#2%
+		\pdfendlink\relax
+	\else
+		#2%
+	\fi
+}
+
+% Typeset a clickable link to the given page number
+% (This does not use named destinations. We use it in tables of contents and indices,
+% where absolute page numbers are known from other sources.)
+% \linkpage{page}{text}
+\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{%
+	\leavevmode
+	\ifclickable
+		\pdfstartlink\commonlinkargs user {/Subtype/Link /A << /Type/Action /S/URI /URI(#1) >>}\relax
+	\fi
+	\xurl #1^^X%
+	\ifclickable
+		\pdfendlink\relax
+	\fi
+}
+\def\xurl#1:#2#3^^X{{\I #1:#2\ifx#2/\kern-0.1em\fi#3}}
diff --git a/ucw-ref.tex b/ucw-ref.tex
index e90b642..74143e2 100644
--- a/ucw-ref.tex
+++ b/ucw-ref.tex
@@ -2,9 +2,7 @@
 % Written by Martin Mares <mj@ucw.cz> in 2018 and placed into public domain
 % -------------------------------------------------------------------------
 
-% Should clickable links be produced?
-\newif\ifclickable
-\clickabletrue
+\input ucw-link.tex
 
 % We maintain a collection of objects. Each object has:
 %    - type (namespace -- e.g., chapter)
@@ -47,9 +45,7 @@
 	\else
 		\edef\currentid{#1\optarg}%
 		\writeid{\currentid}{#2}%
-		\ifclickable
-			\pdfdest name {\currentid} xyz\relax
-		\fi
+		\destpos{\currentid}%
 	\fi
 }
 
@@ -60,41 +56,13 @@
 	{\ifx\bo\undefined\bf\else\bo\fi ??}%
 	\immediate\write16{*** Warning: Reference #1 undefined ***}%
 \else
-	\ifclickable
-		\pdfstartlink\commonlinkargs goto name {#1#2}\relax
-	\fi
-	#3{\csname id:#1#2\endcsname}%
-	\ifclickable
-		\pdfendlink\relax
-	\fi
+	\link{#1#2}{#3{\csname id:#1#2\endcsname}}%
 \fi
 }
 
-% Common style of all clickable links
-\pdflinkmargin=1pt
-\def\commonlinkargs{height \the\dimexpr\ht\strutbox-0.5pt\relax depth \the\dimexpr\dp\strutbox-0.5pt\relax attr {/C [0 0 0.5] /Border [0 0 2]}}
-
 % Typeset a link to identifier #2 of type #1
 \def\ref#1#2{\reflink{#1}{#2}\relax}
 
 % Define an identifier of type page pointing to the current page
-\def\pageid#1{\delayedwriteid{page#1}{\the\count0}\ifclickable\pdfdest name {page#1} fit\relax\fi}
+\def\pageid#1{\delayedwriteid{page#1}{\the\count0}\destpage{page#1}}
 \def\pageref{\ref{page}}
-
-% Typeset a reference to the given page number (used in tables of contents and indices,
-% where we know the page number from other sources).
-\def\pagelink#1{\ifclickable\pdfstartlink\commonlinkargs goto page #1 {/Fit}\relax #1\pdfendlink\else #1\fi}
-
-% Typeset a clickable URL
-% Currently, all weird characters must be properly escaped.
-\def\url#1{%
-	\leavevmode
-	\ifclickable
-		\pdfstartlink\commonlinkargs user {/Subtype/Link /A << /Type/Action /S/URI /URI(#1) >>}\relax
-	\fi
-	\xurl #1^^X%
-	\ifclickable
-		\pdfendlink\relax
-	\fi
-}
-\def\xurl#1:#2#3^^X{{\I #1:#2\ifx#2/\kern-0.1em\fi#3}}
-- 
2.39.2