32.1 Examining Text Near Point

Many functions are provided to look at the characters around point. Several simple functions are described here. See also looking-at in Regular Expression Searching.

In the following four functions, “beginning” or “end” of buffer refers to the beginning or end of the accessible portion.

Function: char-after &optional position

This function returns the character in the current buffer at (i.e., immediately after) position position. If position is out of range for this purpose, either before the beginning of the buffer, or at or beyond the end, then the value is nil. The default for position is point.

In the following example, assume that the first character in the buffer is ‘@’:

(char-to-string (char-after 1)) ⇒ "@"

Function: char-before &optional position

This function returns the character in the current buffer immediately before position position. If position is out of range for this purpose, either at or before the beginning of the buffer, or beyond the end, then the value is nil. The default for position is point.

Function: following-char

This function returns the character following point in the current buffer. This is similar to (char-after (point)). However, if point is at the end of the buffer, then following-char returns 0.

Remember that point is always between characters, and the cursor normally appears over the character following point. Therefore, the character returned by following-char is the character the cursor is over.

In this example, point is between the ‘a’ and the ‘c’.

---------- Buffer: foo ---------- Gentlemen may cry ``Pea∗ce! Peace!,'' but there is no peace. ---------- Buffer: foo ---------- (char-to-string (preceding-char)) ⇒ "a" (char-to-string (following-char)) ⇒ "c"

Function: preceding-char

This function returns the character preceding point in the current buffer. See above, under following-char, for an example. If point is at the beginning of the buffer, preceding-char returns 0.

Function: bobp

This function returns t if point is at the beginning of the buffer. If narrowing is in effect, this means the beginning of the accessible portion of the text. See also point-min in Point.

Function: eobp

This function returns t if point is at the end of the buffer. If narrowing is in effect, this means the end of accessible portion of the text. See also point-max in Voir la section Point.

Function: bolp

This function returns t if point is at the beginning of a line. Voir la section Motion by Text Lines. The beginning of the buffer (or of its accessible portion) always counts as the beginning of a line.

Function: eolp

This function returns t if point is at the end of a line. The end of the buffer (or of its accessible portion) is always considered the end of a line.

Ce document a été généré par Eric Reinbold le 13 Octobre 2007 en utilisant texi2html 1.78.