improvement: consistent use of delimiter

src/awk/approx.awk

@@ -1,5 +1,13 @@
 ## src/awk/approx.awk
+##
 ## Generate single-line approximate information for every iCalendar argument.
+## The fields in each line are separated by "\t"
+## The fields are the following:
+## 1. "~" (constant, indicating that the lines contains approximate information)
+## 2. start (this can be used in date (1))
+## 3. end (this can be used in date (1)
+## 4. string to display
+## 5. filename (collection/name)
 ##
 ## @assign collection_labels: See configuration of the current program.
 
@@ -25,8 +33,8 @@ function fn(path,    n, a) {
 # @return: colorized single-line title string
 function title(start, summary) {
   summary = getcontent(summary)
-  gsub("\n", " ", summary) # This will be put on a single line
-  gsub("\\|",  ":", summary) # we use "|" as delimiter
+  gsub("\n",  " ", summary) # This will be put on a single line
+  gsub("\\t", " ", summary) # we use "\t" as delimiter
   depth = split(FILENAME, path, "/")
   collection = depth > 1 ? path[depth-1] : ""
   collection = collection in collection2label ? collection2label[collection] : collection
@@ -36,7 +44,7 @@ function title(start, summary) {
 # AWK program
 BEGIN {
   FS="[:;=]"
-  OFS="|"
+  OFS="\t"
   split(collection_labels, mapping, ";")
   for (map in mapping)
   {