rules: add some comments to the merge.sh file

Let's make this easier to understand for drive-by reviewers. Replace $i with
$partsfile because it's more expressive. And add a comment on what this
actually does.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

1 files changed, 15 insertions, 5 deletions

diff --git a/rules/merge.sh b/rules/merge.sh
index b18af7c3..6d15c7e7 100755
--- a/rules/merge.sh
+++ b/rules/merge.sh
@@ -1,5 +1,7 @@
 #!/bin/sh
 
+# Usage: merge.sh <output-file> <file1.part> <file2.part> <file3.part> …
+
 INDIR=`dirname $0`
 DEST=$1
 shift
@@ -11,15 +13,23 @@ fi
 basename=`basename $0`
 echo "// DO NOT EDIT THIS FILE - IT WAS AUTOGENERATED BY $basename FROM rules/*.part" >$DEST
 
-for i in $*; do
-  if [ "$i" = "$HDR" ] || [ "$i" = "HDR" ]; then
+# The HDR file contains the headers for each section in the rules file.
+# This is fed as stdin to the for loop below.
+#
+# Wherever the current file is the literal string "HDR", read the next line
+# from that file append it to $DEST
+# Otherwise, take the filename and append it to $DEST.
+#
+
+for partfile in $*; do
+  if [ "$partfile" = "$HDR" ] || [ "$partfile" = "HDR" ]; then
     echo >> $DEST;
     read hdr
     echo "$hdr" >> $DEST
-  elif test -f $i; then
-    cat $i >> $DEST || exit 1
+  elif test -f $partfile; then
+    cat $partfile >> $DEST || exit 1
   else
-    cat $INDIR/$i >> $DEST || exit 1
+    cat $INDIR/$partfile >> $DEST || exit 1
   fi
 done < $HDR