( Definitions Section

Info Catalog ( Format ( Format ( Rules Section
 5.1 Format of the Definitions Section
 The "definitions section" contains declarations of simple "name"
 definitions to simplify the scanner specification, and declarations of
 "start conditions", which are explained in a later section.
    Name definitions have the form:
          name definition
    The `name' is a word beginning with a letter or an underscore (`_')
 followed by zero or more letters, digits, `_', or `-' (dash).  The
 definition is taken to begin at the first non-whitespace character
 following the name and continuing to the end of the line.  The
 definition can subsequently be referred to using `{name}', which will
 expand to `(definition)'.  For example,
          DIGIT    [0-9]
          ID       [a-z][a-z0-9]*
    Defines `DIGIT' to be a regular expression which matches a single
 digit, and `ID' to be a regular expression which matches a letter
 followed by zero-or-more letters-or-digits.  A subsequent reference to
    is identical to
    and matches one-or-more digits followed by a `.' followed by
 zero-or-more digits.
    An unindented comment (i.e., a line beginning with `/*') is copied
 verbatim to the output up to the next `*/'.
    Any _indented_ text or text enclosed in `%{' and `%}' is also copied
 verbatim to the output (with the %{ and %} symbols removed).  The %{
 and %} symbols must appear unindented on lines by themselves.
    A `%top' block is similar to a `%{' ... `%}' block, except that the
 code in a `%top' block is relocated to the _top_ of the generated file,
 before any flex definitions (1).  The `%top' block is useful when you
 want certain preprocessor macros to be defined or certain files to be
 included before the generated code.  The single characters, `{'  and
 `}' are used to delimit the `%top' block, as show in the example below:
              /* This code goes at the "top" of the generated file. */
              #include <stdint.h>
              #include <inttypes.h>
    Multiple `%top' blocks are allowed, and their order is preserved.
    ---------- Footnotes ----------
    (1) Actually, `yyIN_HEADER' is defined before the `%top' block.
Info Catalog ( Format ( Format ( Rules Section
automatically generated byinfo2html