Info Catalog elisp: Position Parse elisp: Parsing Expressions elisp: Low-Level Parsing

elisp: Parser State

 
 34.6.3 Parser State
 -------------------
 
 A “parser state” is a list of ten elements describing the state of the
 syntactic parser, after it parses the text between a specified starting
 point and a specified end point in the buffer.  Parsing functions such
 as ‘syntax-ppss’ (Position Parse) return a parser state as the
 value.  Some parsing functions accept a parser state as an argument, for
 resuming parsing.
 
    Here are the meanings of the elements of the parser state:
 
   0. The depth in parentheses, counting from 0.  *Warning:* this can be
      negative if there are more close parens than open parens between
      the parser’s starting point and end point.
 
   1. The character position of the start of the innermost parenthetical
      grouping containing the stopping point; ‘nil’ if none.
 
   2. The character position of the start of the last complete
      subexpression terminated; ‘nil’ if none.
 
   3. Non-‘nil’ if inside a string.  More precisely, this is the
      character that will terminate the string, or ‘t’ if a generic
      string delimiter character should terminate it.
 
      Syntax Flags::); or the comment nesting level if inside a comment
      that can be nested.
 
   5. ‘t’ if the end point is just after a quote character.
 
   6. The minimum parenthesis depth encountered during this scan.
 
   7. What kind of comment is active: ‘nil’ if not in a comment or in a
      comment of style ‘a’; 1 for a comment of style ‘b’; 2 for a comment
      of style ‘c’; and ‘syntax-table’ for a comment that should be ended
      by a generic comment delimiter character.
 
   8. The string or comment start position.  While inside a comment, this
      is the position where the comment began; while inside a string,
      this is the position where the string began.  When outside of
      strings and comments, this element is ‘nil’.
 
   9. Internal data for continuing the parsing.  The meaning of this data
      is subject to change; it is used if you pass this list as the STATE
      argument to another call.
 
    Elements 1, 2, and 6 are ignored in a state which you pass as an
 argument to continue parsing, and elements 8 and 9 are used only in
 trivial cases.  Those elements are mainly used internally by the parser
 code.
 
    One additional piece of useful information is available from a parser
 state using this function:
 
  -- Function: syntax-ppss-toplevel-pos state
      This function extracts, from parser state STATE, the last position
      scanned in the parse which was at top level in grammatical
      structure.  “At top level” means outside of any parentheses,
      comments, or strings.
 
      The value is ‘nil’ if STATE represents a parse which has arrived at
      a top level position.
 

Info Catalog elisp: Position Parse elisp: Parsing Expressions elisp: Low-Level Parsing