In this section we describe functions for creating, accessing and altering syntax tables.
This function creates a new syntax table. If table is
nil, the parent of the new syntax table is table;
otherwise, the parent is the standard syntax table.
In the new syntax table, all characters are initially given the “inherit” (‘@’) syntax class, i.e., their syntax is inherited from the parent table (see Syntax Class Table).
This function constructs a copy of table and returns it. If
table is omitted or
nil, it returns a copy of the
standard syntax table. Otherwise, an error is signaled if table
is not a syntax table.
modify-syntax-entrychar syntax-descriptor &optional table
This function sets the syntax entry for char according to
syntax-descriptor. char must be a character, or a cons
cell of the form
(min . max); in the latter case,
the function sets the syntax entries for all characters in the range
between min and max, inclusive.
The syntax is changed only for table, which defaults to the current buffer’s syntax table, and not in any other syntax table.
The argument syntax-descriptor is a syntax descriptor, i.e., a string whose first character is a syntax class designator and whose second and subsequent characters optionally specify a matching character and syntax flags. See Syntax Descriptors. An error is signaled if syntax-descriptor is not a valid syntax descriptor.
This function always returns
nil. The old syntax information in
the table for this character is discarded.
;; Put the space character in class whitespace. (modify-syntax-entry ?\s " ") ⇒ nil
;; Make ‘$’ an open parenthesis character, ;; with ‘^’ as its matching close. (modify-syntax-entry ?$ "(^") ⇒ nil
;; Make ‘^’ a close parenthesis character, ;; with ‘$’ as its matching open. (modify-syntax-entry ?^ ")$") ⇒ nil
;; Make ‘/’ a punctuation character, ;; the first character of a start-comment sequence, ;; and the second character of an end-comment sequence. ;; This is used in C mode. (modify-syntax-entry ?/ ". 14") ⇒ nil
This function returns the syntax class of character, represented by its designator character (see Syntax Class Table). This returns only the class, not its matching character or syntax flags.
The following examples apply to C mode. (We use
string to make
it easier to see the character returned by
;; Space characters have whitespace syntax class. (string (char-syntax ?\s)) ⇒ " "
;; Forward slash characters have punctuation syntax. ;; Note that this
char-syntaxcall does not reveal ;; that it is also part of comment-start and -end sequences. (string (char-syntax ?/)) ⇒ "."
;; Open parenthesis characters have open parenthesis syntax. ;; Note that this
char-syntaxcall does not reveal that ;; it has a matching character, ‘)’. (string (char-syntax ?\()) ⇒ "("
This function makes table the syntax table for the current buffer. It returns table.
This function returns the current syntax table, which is the table for the current buffer.
This command displays the contents of the syntax table of buffer (by default, the current buffer) in a help buffer.
This macro executes body using table as the current syntax table. It returns the value of the last form in body, after restoring the old current syntax table.
Since each buffer has its own current syntax table, we should make that
with-syntax-table temporarily alters the current
syntax table of whichever buffer is current at the time the macro
execution starts. Other buffers are not affected.