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flex-lexerlex

flex default rule can be matched

I am working on a flex parser using flex 2.6.4 with the -s option specified, a particular start condition has the following patterns (I am trying to read everything to the next unescaped newline):

\\(.|\n)
[^\\\n]+
\n

Yet I get the warning: "-s option given but default rule can be matched"

I don't see any holes in the above pattern set, am I missing something or is this a flex error?

Solution

  • Your set of rules does not match a backslash at the end of the file.

    Your first rule requires the backslash to be followed by something and the other ones don't match backslashes at all.