(flex.info.gz) Does flex support recursive pattern definitions?

Info Catalog

(flex.info.gz) Why do flex scanners call fileno if it is not ANSI compatible?

(flex.info.gz) FAQ

(flex.info.gz) How do I skip huge chunks of input (tens of megabytes) while using flex?

 
 Does flex support recursive pattern definitions?
 ================================================
 
 e.g.,
 
 
      %%
      block   "{"({block}|{statement})*"}"
 
    No. You cannot have recursive definitions.  The pattern-matching
 power of regular expressions in general (and therefore flex scanners,
 too) is limited.  In particular, regular expressions cannot "balance"
 parentheses to an arbitrary degree.  For example, it's impossible to
 write a regular expression that matches all strings containing the same
 number of '{'s as '}'s.  For more powerful pattern matching, you need a
 parser, such as `GNU bison'.
 

Info Catalog

(flex.info.gz) Why do flex scanners call fileno if it is not ANSI compatible?

(flex.info.gz) FAQ

(flex.info.gz) How do I skip huge chunks of input (tens of megabytes) while using flex?