[C++] Enable CSV Writer to control the type of escape used for quoting

[asfimport]

We would use this for alignment with readr::write_csv(). There the escape argument controls the type of escape to use when quotes are in the data:

• double: quotes are escaped by doubling them
• backslash: quotes are escaped by a preceding backslash
• none: quotes are not escaped

Reporter: Dragoș Moldovan-Grünfeld / @dragosmg

PRs and other links:

• GitHub Pull Request #11857
• GitHub Pull Request #11863

_{Note: This issue was originally created as ARROW-14906. Please see the migration documentation for further details.}

[asfimport]

Neal Richardson / @nealrichardson:
This issue has been inactive for 3 months, so it has been unassigned and marked as unstarted. If you are still working on this, feel free to reassign yourself and resume progress.

[vkhanduja]

is this issue available for take?

[RabahSend]

Hi, I’m interested in working on this issue.

I checked the current CSV writer implementation, and it looks like configurable escaping is still unsupported at write time. WriteOptions already has quoting_style and related options such as eol, but writer.cc still hardcodes double-quote escaping through its Escape() helper.

I also reviewed the previous work in #11863. That PR was closed without being merged, but @pitrou’s API proposal still seems like the most relevant direction:

• QuotingStyle quoting_style (already present)
• bool double_quote
• char escape_char

For context, ParseOptions already exposes double_quote and escape_char for reading, so adding similar options to WriteOptions would keep the APIs consistent.

Before starting, I’d like to confirm:

1. Is @pitrou’s proposal still the preferred design for the current codebase?
2. How should readr’s escape = "none" behaviour be represented: should the writer reject values containing quotes, or allow unescaped quotes inside quoted fields?
3. Should this issue initially be limited to the C++ implementation and tests, with language bindings handled separately?

If this direction is still relevant, I’d be happy to work on the implementation and regression tests.

[kou]

Could you open a PR for discussion?

[waterWang]

I have opened PR #50846 to implement configurable escape control for the CSV writer. This adds an EscapeStyle enum (Double, Backslash, None) to WriteOptions, providing the three escape modes described in this issue: double-quote escaping (default, RFC4180), backslash escaping, and no escaping. @kou this addresses your earlier request to open a PR for discussion.