Add helper to get the value of an alias only

lib/functions.zsh

@@ -15,3 +15,33 @@ function take() {
   cd $1
 }
 
+#
+# Get the value of an alias.
+#
+# Arguments:
+#    1. alias - The alias to get its value from
+# STDOUT:
+#    The value of alias $1 (if it has one).
+# Return value:
+#    0 if the alias was found,
+#    1 if it does not exist
+#
+function alias_value() {
+    alias "$1" | sed "s/^$1='\(.*\)'$/\1/"
+    test $(alias "$1")
+}
+
+#
+# Try to get the value of an alias,
+# otherwise return the input.
+#
+# Arguments:
+#    1. alias - The alias to get its value from
+# STDOUT:
+#    The value of alias $1, or $1 if there is no alias $1.
+# Return value:
+#    Always 0
+#
+function try_alias_value() {
+    alias_value "$1" || echo "$1"
+}