cleaned awk scripts, str escape bugfix, proper use of local variables

src/awk/set.awk

@@ -1,13 +1,31 @@
+## src/awk/set.awk
+## Set or replace the content of a specified field in the iCalendar file.
+##
+## @assign field: iCalendar field
+## @assign value: Content to set it to
+##
+## LIMITATION: This program does not fold long content lines.
+
+# Functions
+
+# escape
+# Escape string to be used as content.
+#
+# @input str: Content string
+# @return: Escaped string
 function escape(str)
 {
-  gsub("\\\\", "\\\\", str)
-  gsub(";",  "\\\\;",  str)
-  gsub(",",  "\\\\,",  str)
+  gsub("\\\\", "\\\\",   str)
+  gsub(";",    "\\\\;",  str)
+  gsub(",",    "\\\\,",  str)
   return str
 }
-BEGIN { FS = "[:;]"; }
+
+# AWK program
+
+BEGIN                 { FS = "[:;]" }
 /^BEGIN:VEVENT$/      { inside = 1 }
-/^END:VEVENT$/        { inside = 0 }
+/^END:VEVENT$/        { inside = 0; if (!duplic) print field ":" escape(value) }
 $1 == field && inside { con = 1; duplic = 1; print field ":" escape(value); next }
 $1 == field && duplic { con = 1; next }
 /^ / && con           { next }