Re^2: Regular expression for hexadecimal number

Hmm, this answers a question that's been in the back of my mind for a while, "Can you turn on/off modifiers in the middle of a regex."

Thanks for prompting me to pop over to Perldoc to learn about it.

A question, though: The goal is to keep the 0x case sensitive (to disallow 0X, as you said), but let the hex that follows match in a case insensitive way (i.e. match both 0xFF and 0xff)? If so, doesn't (?-i:PATTERN) actually turn off the insensitivity modifier (which wasn't on?). Based on my (probably wrong) interpretation of what I just learned at Perldoc, it seems like you'd want (?i:PATTERN) to turn it on.

Comment on Re^2: Regular expression for hexadecimal number

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Re^3: Regular expression for hexadecimal number by radiantmatrix (Parson) on Jul 30, 2007 at 15:13 UTC
What you describe is accomplished not by using a modifier, but by being explicit in the definition of the char class: `m/0x[\da-fA-F]{1,4}/;` [download] There's no reason to have or use modifiers on only part of a regex, when one can simply use the mechanisms already available to accomplish the same goal. <–radiant.matrix–> Ramblings and references The Code that can be seen is not the true Code I haven't found a problem yet that can't be solved by a well-placed trebuchet	[reply] [d/l]

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Re^3: Regular expression for hexadecimal number
by radiantmatrix (Parson) on Jul 30, 2007 at 15:13 UTC

What you describe is accomplished not by using a modifier, but by being explicit in the definition of the char class:

m/0x[\da-fA-F]{1,4}/;
[download]

There's no reason to have or use modifiers on only part of a regex, when one can simply use the mechanisms already available to accomplish the same goal.

<–radiant.matrix–>
Ramblings and references
The Code that can be seen is not the true Code
I haven't found a problem yet that can't be solved by a well-placed trebuchet

[reply]
[d/l]