course: use a proper type to iterate over a course description

Currently, to find a course's summary and location, there is a
pattern matching over a ad-hoc 3-uple of a boolean and two strings.
To make it clear, this badly defined structure is replaced by an
actual ADT, `loc_and_sum', containing 4 cases:

 - `Nothing', when the groups has not been found yet;
 - `Groups', when the groups has been found by `check_groups'.  This
   means that the next line should be the course's location;
 - `Location', when the location has been found.  If there is no new
   line to read, the string is the location, otherwise it's the
   summary, and the next line should be the actual location;
 - `Summary', when the location and summary has been both found.  All
   subsequent lines will be ignored.

A function is also added to convert a `loc_and_sum' to a couple of
string containing the location and the summary.

Signed-off-by: Alban Gruin <alban at pa1ch dot fr>

0 files changed, 0 insertions, 0 deletions