hledger has builtin support for four formats so far (journal, timeclock, timedot, csv). The current journal format can be quite light:

  1/1
   (food)  5
  1/2
   (car)  15

But I'll sometimes use csv for quick one-line entries:

  1/1,food,5
  1/2,car,15

Some hledger users have their own custom formats like you, and use a script to preprocess it. More format experiments are always welcome.

An advantage of something like hledger over a home-grown script is more robust and versatile reporting.