Docstring for match-beginning

[uzibalqa]

Having read the docstring for match-beginning, the sentence "SUBEXP, a number, 
specifies which parenthesized expression in the last regexp." seems incomplete 
because it lacks a clear explanation (purpose or context) of what the 
specification
of the parenthesized expression accomplishes or how it is used.  

To make the sentence complete, it needs an additional clause that clarifies the 
outcome or the role of specifying the parenthesized expression.

Here's an example of a more complete sentence:

"SUBEXP, a number, specifies which parenthesized expression in the last regexp 
to extract or manipulate, providing precise control over the parts of the match 
that are used."

--------

(match-beginning SUBEXP)

Return position of start of text matched by last search.

SUBEXP, a number, specifies which parenthesized expression 
in the last regexp.