36 — Diary: writing it down with today's date

A diary needs when it was written. Typing the date by hand goes wrong and gets forgotten. The computer already knows it, so ask it.

A program that writes files does not run on the site.

#Steps

1. Open the date tools. One line brings the words that ask about dates:

   use date latest
   show today
   show weekday
   show year
   

   copyrun it →

   Something like 2026-08-19, Wednesday, 2026. The clock is UTC — with a different clock per country the same program would answer differently for different people.

2. Put the date in a name so it can be used more than once:

   use date latest
   set stamp to today
   set day to weekday
   show stamp
   show day
   

   copyrun it →

3. Put the date, the weekday and the note into one line. It is the shape from guide 40:

   set stamp to "2026-08-19"
   set day to Wednesday
   set note to it rained a little
   set lines to an empty list
   append stamp to lines
   append day to lines
   append note to lines
   set row to lines joined by comma
   show row
   

   copyrun it →

   2026-08-19, Wednesday, it rained a little. A date typed by hand needs quotes — 2026-08-19 on its own reads as a sum with subtraction in it. What today() hands you needs none.

4. Save it, read it back, take the fields out:

   set row to "2026-08-19, Wednesday, it rained a little"
   write row to "diary.txt"
   read "diary.txt" into memo
   set fields to memo split by comma
   show the first of fields
   show the last of fields
   

   copyrun it →

5. The whole thing:

   use date latest
   set stamp to today
   set day to weekday
   set note to it rained a little
   set lines to an empty list
   append stamp to lines
   append day to lines
   append note to lines
   set row to lines joined by comma
   write row to "diary.txt"
   read "diary.txt" into memo
   show memo
   

   copyrun it →

#Try it yourself

Add days_after(7) to write down what the date will be a week from now; days_after(-1) is yesterday. Then ask for the note and it becomes a real diary — except that it overwrites. Keeping entries means reading what is there, adding to a list, and writing the whole thing back.

#What you learned

• One line of use date latest brings today(), weekday(), year() and days_after(n).
• Put a date in a name and use it as often as you like.
• Date, weekday and note joined by commas make a one-line record.
• The clock is UTC, so the program answers the same for everyone.