add more detailed implementation note

1 files changed, 14 insertions, 0 deletions

diff --git a/examples/rifle_sxiv.sh b/examples/rifle_sxiv.sh
index 35c65da9..f65524a8 100755
--- a/examples/rifle_sxiv.sh
+++ b/examples/rifle_sxiv.sh
@@ -14,6 +14,20 @@
 # shell syntax and calls being made to external utilities, such as grep or find.
 # This makes it portable across many unix like systems, although it may not be
 # the cleanest or fastest approach.
+#
+# First, using case statement to get absolute path is quicker than calling
+# 'realpath' because it would fork a whole process, which is slow.
+#
+# Second, we need to append a file list to sxiv, which can only be done
+# properly in three ways: arrays (which are not POSIX) or \0 sperated strings.
+# Unfortunately, assigning \0 to a variable is not POSIX either (will not work
+# in dash and others), so we cannot store the result of listfiles to a
+# variable.
+#
+# The third approach is to store the result to a tmpfile and using `-i` to feed
+# the list to sxiv. This is the fastest approach since we won't have to call
+# listfiles twice.
+
 
 tmp="/tmp/sxiv_rifle_$$"