Issue/3200 pathfinder diagnostic

[mitzimorris]

Submission Checklist

• Run unit tests: ./runTests.py src/test/unit
• Run cpplint: make cpplint
• Declare copyright holder and open-source license: see below

Summary

Add hooks to json_writer to put newlines around records and update single-path pathfinder accordingly.

• begin_record takes optional arg "newline"; if true, will output newline before record start or key.
• end_record takes optional arg "newline"; if true, puts newline after record end, furthermore, final close record will be on its own line.

Also got rid of all calls to boost::lexical_cast - see #3201

Intended Effect

Produce readable-ish JSON; output file will be properly terminated, diagnostics from each iteration are on their own line.

How to Verify

Unit tests.

Side Effects

N/A

Documentation

N/A

Copyright and Licensing

Please list the copyright holder for the work you are submitting (this will be you or your assignee, such as a university or company): Columbia University

By submitting this pull request, the copyright holder is agreeing to license the submitted work under the following licenses:

• Code: BSD 3-clause (https://opensource.org/licenses/BSD-3-Clause)
• Documentation: CC-BY 4.0 (https://creativecommons.org/licenses/by/4.0/)

[mitzimorris]

is there a pathfinder unit test that checks output files? if so, can add tests for single-path pathfinder.

[WardBrian]

How ugly is it to always emit newlines after closing records? I feel like adding a flag for this is not the cleanest solution

[mitzimorris]

we would have to add "write_newline" to json_writer. also a fine way to go and much much simpler and would probably improve code readability, plus flexibility.

shall I re-implement?

[mitzimorris]

I realize that breaking iterations out by line is completely unneccessary. the minimal fix for this PR is just adding the "newline" method, no fanciness w/r/t comma between records.

if the reviewers prefer, I can simplify the PR and leave the diagnostic JSON as is, simply adding a newline at the end.

[WardBrian]

I think I prefer simpler. I wouldn’t be opposed to automatically adding new lines at the end of lists/records, if that produces desirable output, but doing it case by case seems clunky

[mitzimorris]

simplified. will try to remember this for next time.

[SteveBronder]

lgtm!