Info Catalog elisp: Syntax Descriptors elisp: Syntax Tables elisp: Syntax Properties

elisp: Syntax Table Functions

 
 34.3 Syntax Table Functions
 ===========================
 
 In this section we describe functions for creating, accessing and
 altering syntax tables.
 
  -- Function: make-syntax-table &optional table
      This function creates a new syntax table.  If TABLE is non-‘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 (Syntax Class Table).
 
  -- Function: copy-syntax-table &optional 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.
 
  -- Command: modify-syntax-entry char 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.  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.
 
      Examples:
 
           ;; 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
 
  -- Function: char-syntax character
      This function returns the syntax class of CHARACTER, represented by
      its designator character (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 ‘char-syntax’.)
 
           ;; Space characters have whitespace syntax class.
           (string (char-syntax ?\s))
                ⇒ " "
 
           ;; Forward slash characters have punctuation syntax.
           ;; Note that this char-syntax call 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-syntax call does not reveal that
           ;; it has a matching character, ‘)’.
           (string (char-syntax ?\())
                ⇒ "("
 
  -- Function: set-syntax-table table
      This function makes TABLE the syntax table for the current buffer.
      It returns TABLE.
 
  -- Function: syntax-table
      This function returns the current syntax table, which is the table
      for the current buffer.
 
  -- Command: describe-syntax &optional buffer
      This command displays the contents of the syntax table of BUFFER
      (by default, the current buffer) in a help buffer.
 
  -- Macro: with-syntax-table table body...
      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 more precise: ‘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.
 

Info Catalog elisp: Syntax Descriptors elisp: Syntax Tables elisp: Syntax Properties