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
(see 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:
nilif inside a string. More precisely, this is the character that will terminate the string, or
tif a generic string delimiter character should terminate it.
tif inside a non-nestable comment (of any comment style; see Syntax Flags); or the comment nesting level if inside a comment that can be nested.
tif the end point is just after a quote character.
nilif 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-tablefor a comment that should be ended by a generic comment delimiter character.
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:
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
nilif state represents a parse which has arrived at a top level position.