11.3.3 Ending a Sentence

As mentioned above, Texinfo normally inserts additional space after the end of a sentence. It uses the same heuristic for this as TeX: a sentence ends with a period, exclamation point, or question mark, either preceded or followed by optional closing punctuation, and then whitespace, and not preceded by a capital letter.

Use @. instead of a period, @! instead of an exclamation point, and @? instead of a question mark at the end of a sentence that does end with a capital letter. Do not put braces after any of these commands. For example:

Give it to M.I.B. and to M.E.W@.  Also, give it to R.J.C@.
Give it to M.I.B. and to M.E.W.  Also, give it to R.J.C.

The output follows. In printed output and Info, you can see the desired extra whitespace after the ‘W’ in the first line.

Give it to M.I.B. and to M.E.W. Also, give it to R.J.C.
Give it to M.I.B. and to M.E.W. Also, give it to R.J.C.

In the HTML output, @. is equivalent to a simple ‘.’; likewise for @! and @?.

The “closing punctuation” mentioned above is defined as a right parenthesis (‘)’, right bracket (‘]’), or right quote, either single or double (‘'’ and ‘''’; the many possible additional Unicode right quotes are not included). These characters can be thought of as invisible with respect to whether a given period ends a sentence. (This is the same rule as TeX.) For instance, the periods in ‘foo.) Bar’ and ‘foo.'' Bar’ do end sentences.

The meanings of @: and @., etc. in Texinfo are designed to work well with the Emacs sentence motion commands (see Sentences in The GNU Emacs Manual). It may help to imagine that the ‘@’ in ‘@.’, etc., is an invisible lower-case letter ‘a’ which makes an upper-case letter before it immaterial for the purposes of deciding whether the period ends the sentence.

A few Texinfo commands are not considered as being an abbreviation, even though they may end with a capital letter when expanded, so that you don’t have to insert @. and companions. Notably, this is the case for code-like highlighting commands, @var arguments ending with a capital letter, @LaTeX, and @TeX. For example, that sentence ended with ‘... @code{@@TeX}.’; @. was not needed. Similarly, in ... @var{VARNAME}. Text the period after VARNAME ends the sentence; there is no need to use @..