[GSoC] Unify ref-filter formats with other --pretty formats

[Kapil Jain <jkapil.cs@gmail.com>]

Hi,

Below are some two queries concerning
https://git.github.io/SoC-2019-Ideas/#unify-ref-filter-formats-with-other---pretty-formats

Q1)

In pretty.h & pretty.c:
void get_commit_format(const char *arg, struct rev_info *);
This function Parses given arguments from "arg", checks it for
correctness and * fill struct rev_info.

In ref-filter.h & ref-filter.c:
int verify_ref_format(struct ref_format *format);
This function is Used to verify if the given format is correct and to
parse out the used atoms.

Now, the verify_ref_format function can be used inside
get_commit_format function, hence reusing logic.
Is this a correct example to work on, for this project ?
If not, please point out an example so as to understand the problem
statement better.

Other than this I can't find any other example, for this project in
pretty.* and ref-filter.*
Perhaps some examples could be found in command specific files, right ?

Q2)
About a recurring term 'atom' in ref-filter and pretty:
what is atom ? is it a piece of a whole document ? and what is meant
by used atoms ?

Thanks.