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Postings from March 2001
Chris Stith <mischief@velma.motion.net> writes: >That is so if the examples are taken exactly as is. It is not so if >the example is put in the context of code following it. From which >match operator would the next line pull `$1'? > >Nick is talking about a body of code expecting something to be a >certain way when the code example above is executed. No I am not. (The example code is not mine and not a good example. It has && in it, is calling a builtin as a pseudo-sub and ...) I am talking about code that uses $1 in general, and with at least a basic grasp of how the op tree is built. And with a background in devious "lexing" schemes. Without a lot of flow analysis (that perl does not do) perl cannot tell that a particular use of $1 is (always) used in a way that means it should take a copy, or a way which means it should leave it "lazy". So my stance is that $1 is lazy, if you want/need a copy then write "$1". >A line of >code following the above example shouldn't expect one or the other >expression to be either `first' or `last', let alone expect which one >will be the value of `$1'. Things get less clear when you have something like: some_sub( (s/(0x([a-f0-9]+))/another_sub($1)/ie || s/(\d+)/third($1)/e) ? $1 : ... ); In such cases "lazy" is what _I_ want for that last one at least and only by a lot of looking do you know which that is. > >Chris Stith -- Nick Ing-Simmons