bpo-21018: document how to escape characters in configparser

[arunpersaud]

Document how $ and % can be escaped in configparser.

https://bugs.python.org/issue21018

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[csabella]

I built the docs and these changes LGTM. @ambv or @berkerpeksag, would you be able to approve and merge? Thanks!

[berkerpeksag]

I'd still prefer only adding examples to the "Interpolation of values" section at https://docs.python.org/3/library/configparser.html#interpolation-of-values There is no need to explicitly document the escape characters. IMO, adding examples with a short comment would be better.

For example:

[Settings]
frequency: %%80

(I'm open to use more meaningful and close to real world examples :))

[arunpersaud]

The problem with just an example for me is that it is not clear which characters one needs to escape and which not, being explicit about it seems better to me. But I'm open to whatever you guys prefer. If it is just an example I would suggest to add a comment

[Settings]
phase: 80%%  # use a %% to escape the % sign (% is the only character that needs to be escaped)

[Settings]
cost: $$80  # use a $$ to escape the $ sign ($ is the only character that needs to be escaped)

[berkerpeksag]

Your suggested example is much better than mine.

[arunpersaud]

Let me know what you want me to do... Should I change this pull request, create a new one, if so, do I need to rebase or can I just amend my request?

[berkerpeksag]

@arunpersaud yes, please update the PR. Rebasing your branch would be good, but not required unless it has merge conflicts.

[arunpersaud]

Updated my branch. Let me know if this is OK or if other changes are needed.

[miss-islington]

Thanks @arunpersaud for the PR, and @JulienPalard for merging it 🌮🎉.. I'm working now to backport this PR to: 3.7.
🐍🍒⛏🤖

[bedevere-bot]

GH-15845 is a backport of this pull request to the 3.7 branch.

[JulienPalard]

Thanks @arunpersaud for this PR!

[miss-islington]

Thanks @arunpersaud for the PR, and @JulienPalard for merging it 🌮🎉.. I'm working now to backport this PR to: 3.8.
🐍🍒⛏🤖 I'm not a witch! I'm not a witch!

[bedevere-bot]

GH-15846 is a backport of this pull request to the 3.8 branch.