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Postings from March 2013
Dave Mitchell wrote: >1) the test script (and thus presumably Regexp::Grammars) only worked >because it was inadvertently exploiting a hole in the "use re eval" >mechanism, and that perl 5.17.x is correctly refusing to execute the code; The qr constant overloading behaves in a rather strange way, compared to operator overloading. After the R:G:Precursor object has been built up by the constant-overload function, it gets stringified, invoking the "" operator overload on R:G:Precursor. The problem is that the resulting string gets compiled to a regexp object by the core, not by the module or the calling program: where the re-eval setting matters, there's no way to set it. You'd think you could avoid this problem by making R:G return a compiled regexp somewhere instead of a string: it can set re-eval for its explicit compilation. But the core is apparently quite insistent on reducing the qr-constant to a string. If the constant-overload function returns a compiled regexp, that gets stringified. If the "" operator overload returns a compiled regexp, that gets stringified. If the "" operator overload returns a ref to an object with more operator overloading, that gets stringified. qr operator overloading never gets invoked. I reckon the qr constant overload should be allowed to return a compiled regexp, to be used as-is rather than stringified. -zeframThread Previous | Thread Next