Improve parsing for add and schedule

[rachx]

Initially, I wanted to reject other formats other than

1. add a task name
2. add do something by (time)
3. add attend something from (time) to (time)
   so things like
4. add read something to (time) will fail but the problem is natty reads number as time (so it does not help when we try to add back to the title string)
   This fails:add i have alot of things to do for 2103

What we can do

1. acknowledge that it will be wrong. provide ways to overcome it e.g. don't parse what is enclosed in inverted commas etc
2. check for a) by or b) from+to otherwise c) add everything to the task string. No throwing incorrect command format.
3. Make it compulsory to use /by or -by instead

comment here or update user guide on implementation

[burnflare]

I like option 2. Here's what we can do:

Either of these criteria must be true:

• command has both from && to
• command has one by

If either of them are not true, we take the entire command as a name string

[rachx]

Remember to add it back to the task string. Usually we don't and we shouldn't if it can be parsed as a date time

[burnflare]

I found out why the use case wasn't working!

The parser takes the input do for 2103 and returns a DateTime object for today 9:03pm. That's why it's failing.

[burnflare]

Wait never mind, this is what you already said originally

[rachx]

and nothing will fix add copy notes from cs2101 to cs2103.
natty think it is 2 years

[rachx]

i think just accept that there is an error. but there must be a way for the user to input add "copy notes from cs2101 to cs2103". like don't read between inverted commas.

[burnflare]

Will do. Working on "" support

[rachx]

can normal tasks have inverted commas in their name then? some of our screenshots have a task: return "Animal Farm". might need to change afterwards