forward-paragraph: a Goldmine of FunctionsThe forward-paragraph function moves point forward to the end
of the paragraph. It is usually bound to M-} and makes use of a
number of functions that are important in themselves, including
let*, match-beginning, and looking-at.
The function definition for forward-paragraph is considerably
longer than the function definition for forward-sentence
because it works with a paragraph, each line of which may begin with a
fill prefix.
A fill prefix consists of a string of characters that are repeated at the beginning of each line. For example, in Lisp code, it is a convention to start each line of a paragraph-long comment with ‘;;; ’. In Text mode, four blank spaces make up another common fill prefix, creating an indented paragraph. (See Fill Prefix in The GNU Emacs Manual, for more information about fill prefixes.)
The existence of a fill prefix means that in addition to being able to
find the end of a paragraph whose lines begin on the left-most
column, the forward-paragraph function must be able to find the
end of a paragraph when all or many of the lines in the buffer begin
with the fill prefix.
Moreover, it is sometimes practical to ignore a fill prefix that exists, especially when blank lines separate paragraphs. This is an added complication.