illogical punctuation and non french spacing

Question

There is a convention in American typesetting that punctuation marks such as commas and periods should not come immediately after a closing quotation mark; instead they should be moved inside. It seems to me that this creates an obvious problem that I've never seen discussed anywhere: how much space goes after the closing quotation mark?? Since the sentence just ended, it seems an inter-sentence space is fitting, especially since quote marks are bigger than periods and hence more likely to seem "too close" to the following text. But TeX won't do this by default, and I can't think of a way to accomplish this that doesn't seem terribly hacky. But surely this is a common problem faced by millions of people, and thousands of them use LaTeX. What gives?

MWE:

\documentclass{minimal}
\begin{document}
'.  9  % inter-sentence space

.'  9  % inter-word space
\end{document}

Answer 1

No matter whether you type .' or '., the following space will be an “end-of-sentence” space.

\documentclass{article}

\begin{document}

`Hello.' World

`Hello'. World

`Hello'.\ World

\end{document}

You can clearly see the difference: the last line has control-space, which ignores end of sentence spacing. The first two lines have exactly the same space. This is because the space factor code of ' is 0, so it's ignored by the space factor computations.

If you want that the first case is not considered an end-of-sentence in any case, just assign a new space factor code to ':

\sfcode`'=1000