Re: my vs. local subtlety

[esr]

As stated in the original post, it was not my intention to suggest that this code was the only or best way to accomplish what I was trying to do. I could obviously have passed an array of array references or any number of other things rather than an array of letters. I posted it only because I thought it might be helpful to others to note the subtle "gotcha" between defining variables with "my" and with "local" when using a construct such as $$ctm.

As you noted, using $a and $b was an unfortunate choice in the snippet example but those names were chosen for brevity in the example, not as a model of good code.

[davidrw]

I posted it only because I thought it might be helpful to others to note the subtle "gotcha" between defining variables with "my" and with "local" when using a construct such as $$ctm.

right, but my point was that if they don't use that construct, and instead use a safer, more robust, versatile, and maintainable construct, then the "gotcha" doesn't even exist ... IMHO I just saw it as recommending that one wear gloves when punching a wasp nest out of a tree -- the first thing anyone is gonna ask is "why aren't you using a ten-foot pole?".
As quoted from the article (it's a good read if you haven't yet) i mentioned above, (Summary #2) Being careful does not mean trying to understand the possible consequences while behaving dangerously; it means avoiding dangerous behavior in the first place. Don't say ``I know it's dangerous, so I'll be really careful.'' Say ``I know it's dangerous, so I won't do it.''

[ysth]

I thought it might be helpful to others to note the subtle "gotcha" between defining variables with "my" and with "local" when using a construct such as $$ctm.

Or a construct such as $#$arrnm or $$arrnm[$$ctm]. That is to say, your @out_a, etc. arrays also cannot be lexical (my) variables.

The distinction isn't between my and local, it's between lexical and package variables. Symbolic refs (which look up a variable by an expression giving it's name) always find package variables, not lexical ones.