From 564a3e2ec83e3883cafe9efd2c6f88144a0835db Mon Sep 17 00:00:00 2001
From: Einhard Leichtfuß <alguien@respiranto.de>
Date: Sun, 23 Dec 2018 05:58:13 +0100
Subject: Simplify basic.sh:replace_line and switch to EREs

EREs: extended regular expressions in contrast to basic regular
      expressions (BREs).
---
 basic.sh | 32 ++++++++++++++++++++------------
 1 file changed, 20 insertions(+), 12 deletions(-)

(limited to 'basic.sh')

diff --git a/basic.sh b/basic.sh
index ed4a442..7740978 100644
--- a/basic.sh
+++ b/basic.sh
@@ -3,6 +3,8 @@
 # Copyright 2018 Einhard Leichtfuß
 #
 
+# All methods operate on the file "$tmp".
+
 typeset -a langs
 langs=(
 	fra-deu deu-fra
@@ -31,37 +33,43 @@ function cleanup
 }
 trap cleanup EXIT
 
-# $1: string to replace: regular expression
+# $1: string to replace: extended regular expression
 # $2: string to replace with: sed replacement string
 function replace
 {
-	sed -i "s/${1}/${2}/g" "$tmp"
+	sed -Ei "s/${1}/${2}/g" "$tmp"
 }
 
-# $1 line to replace: regular expression
+# Replace line by a string (possibly including newlines).
+# $1 line to replace: extended regular expression
 # $2 text to replace with: (newline terminated) sed replacement string
 # $3 removal type: (rm-plus-one|normal)
+#   `- If $2 is empty, whether to remove only that line or also the one
+#      following.
 function replace_line
 {
 	if test -n "$2"
 	then
-		cat <(sed "/${1}/,\$ d" < "$tmp") \
-			<(echo -n "$2") \
-			<(sed "0,/${1}/ d" < "$tmp") \
-			> "$tmp_"
-		mv "$tmp_" "$tmp"
+		printf '%s' "$2" > "$tmp_"
+
+		sed -Ei "
+			/${1}/ {
+				r $tmp_
+				d
+			}
+			" "$tmp"
 	else
 		if [[ "$3" == rm-plus-one ]]
 		then
-			sed -i "/${1}/,+1 d" "$tmp"
+			sed -Ei "/${1}/,+1 d" "$tmp"
 		else
-			sed -i "/${1}/ d" "$tmp"
+			sed -Ei "/${1}/ d" "$tmp"
 		fi
 	fi
 }
 
-# $1 line to delete: regular expression
+# $1 line to delete: extended regular expression
 function delete_line
 {
-	sed -i "/${1}/ d" "$tmp"
+	sed -Ei "/${1}/ d" "$tmp"
 }
-- 
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