Re: Input buffer overflow in lex...

In the version of "lex" I use, the generated lexer gets its input via an
"input" macro. One solution, which may be viewed as a "kludge" or "hack",
is to "#undef" the default macro and "#define" another with the same
functionality, but which also checks for overflow (and possibly takes some
recovery action, like copy what's in the buffer to an "infinitely" long
linked-list of buffers).


For example:


        %{
        #undef input


        #define usual_input_macro() (...text of default "input" definition...)


        #define input() ( \
('\0' != *(yytext + YYLMAX - 1)) \
? (token_too_long()) \
: usual_input_macro() \
)


        #define token_too_long() (...recovery action...)


:




Disclaimer: I've never tried this.


Lets hope I'm not being blind to some reason this can't work. I
personally prefer this than just bumping YYLMAX, which may be fine,
practically speaking, but still nags in that it just begs the question.


Hope this helps,


Rich Wagner
Intermetrics, Inc.
[I still think you're better off writing your lexer so you don't get
enormous tokens. -John]
--

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