From 5b4358819a1af8dec70722491d32c8863ba65423 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?John=20Ankarstr=C3=B6m?= <john@ankarstrom.se>
Date: Thu, 17 Jun 2021 20:14:53 +0200
Subject: wpdf: Rewrite in Perl

---
 wpdf | 52 ++++++++++++++++++++++++++++++++--------------------
 1 file changed, 32 insertions(+), 20 deletions(-)

diff --git a/wpdf b/wpdf
index df9c71a..3a362ca 100755
--- a/wpdf
+++ b/wpdf
@@ -1,25 +1,37 @@
-#!/bin/sh
+#!/usr/bin/perl
 
-# wpdf -- view, watch and remake pdf
+# wpdf -- view, watch and remake pdf based on Makefile
 
-IFS='
-'
+use strict;
+use warnings;
 
-[ -z "$*" ] && { echo usage: $0 source-file ... 1>&2; exit 1; }
+my %deps;
 
-success=
-for source in "$@"; do
-	case $source in
-	*.pdf)	echo skipping $source: already a pdf 1>&2 ;;
-	*)	success=1
-		xpdf -remote wpdf-$source ${source%.*}.pdf & ;;
-	esac
-done
+# collect dependencies for given pdf files
+for (@ARGV) {
+	if (/\.pdf$/) {
+		(my $name = $_) =~ s/\.pdf$//;
+		open my $f, '<', 'Makefile'
+			or die "could not open Makefile: $!\n";
+		while (<$f>) {
+			if (/^\Q$name.pdf\E:\s*(.*)/) {
+				$deps{$_} = $name for split /\s/, $1;
+				last;
+			}
+		}
+		close $f;
+		exec('xpdf', '-remote', "wpdf-$name", "$name.pdf") if fork == 0;
+	} else {
+		warn "skipping $_: not a pdf\n";
+	}
+}
 
-[ -z "$success" ] && exit 1
-xdotool search --sync --onlyvisible --class xpdf 1>&-
-sleep 0.2 || sleep 1
-
-watch -i "$@" | while read source; do
-	make ${source%.*}.pdf && xpdf -remote wpdf-$source -reload
-done
+# make pdf on demand
+open my $p, '-|', 'watch', keys %deps
+	or die "could not start watch: $!\n";
+while (<$p>) {
+	chomp;
+	system('make', "$deps{$_}.pdf") == 0
+		&& system('xpdf', '-remote', "wpdf-$deps{$_}", '-reload');
+}
+close $p;
-- 
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