elisp: Word Motion
29.2.2 Motion by Words
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The functions for parsing words described below use the syntax table and
‘char-script-table’ to decide whether a given character is part of a
word. 
Syntax Tables, and see Character Properties.
-- Command: forward-word &optional count
This function moves point forward COUNT words (or backward if COUNT
is negative). If COUNT is omitted or ‘nil’, it defaults to 1. In
an interactive call, COUNT is specified by the numeric prefix
argument.
“Moving one word” means moving until point crosses a
word-constituent character, which indicates the beginning of a
word, and then continue moving until the word ends. By default,
characters that begin and end words, known as “word boundaries”,
are defined by the current buffer’s syntax table (Syntax
Class Table), but modes can override that by setting up a
suitable ‘find-word-boundary-function-table’, described below.
Characters that belong to different scripts (as defined by
‘char-syntax-table’), also define a word boundary (Character
Properties). In any case, this function cannot move point past
the boundary of the accessible portion of the buffer, or across a
field boundary (Fields). The most common case of a field
boundary is the end of the prompt in the minibuffer.
If it is possible to move COUNT words, without being stopped
prematurely by the buffer boundary or a field boundary, the value
is ‘t’. Otherwise, the return value is ‘nil’ and point stops at
the buffer boundary or field boundary.
If ‘inhibit-field-text-motion’ is non-‘nil’, this function ignores
field boundaries.
-- Command: backward-word &optional count
This function is just like ‘forward-word’, except that it moves
backward until encountering the front of a word, rather than
forward.
-- User Option: words-include-escapes
This variable affects the behavior of ‘forward-word’ and
‘backward-word’, and everything that uses them. If it is
non-‘nil’, then characters in the escape and character-quote syntax
classes count as part of words. Otherwise, they do not.
-- Variable: inhibit-field-text-motion
If this variable is non-‘nil’, certain motion functions including
‘forward-word’, ‘forward-sentence’, and ‘forward-paragraph’ ignore
field boundaries.
-- Variable: find-word-boundary-function-table
This variable affects the behavior of ‘forward-word’ and
‘backward-word’, and everything that uses them. Its value is a
char-table (Char-Tables) of functions to search for word
boundaries. If a character has a non-‘nil’ entry in this table,
then when a word starts or ends with that character, the
corresponding function will be called with 2 arguments: POS and
LIMIT. The function should return the position of the other word
boundary. Specifically, if POS is smaller than LIMIT, then POS is
at the beginning of a word, and the function should return the
position after the last character of the word; otherwise, POS is at
the last character of a word, and the function should return the
position of that word’s first character.
-- Function: forward-word-strictly &optional count
This function is like ‘forward-word’, but it is not affected by
‘find-word-boundary-function-table’. Lisp programs that should not
change behavior when word movement is modified by modes which set
that table, such as ‘subword-mode’, should use this function
instead of ‘forward-word’.
-- Function: backward-word-strictly &optional count
This function is like ‘backward-word’, but it is not affected by
‘find-word-boundary-function-table’. Like with
‘forward-word-strictly’, use this function instead of
‘backward-word’ when movement by words should only consider syntax
tables.
Info Catalog
elisp: Character Motion
elisp: Motion
elisp: Buffer End Motion