Re: Matching nested parens

An alternative approach is to iterate over each charactor; when you see a ( push it on the stack array (and change some "state" variable, maybe a "depth count" which is also the size of the stack); then when you see a ), pop the top of the stack (will be a (). Based on the depth of the nesting (or size of the stack) you can do all sorts of things with the intervening characters you see.

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Re^2: Matching nested parens by jcb (Parson) on Oct 06, 2020 at 23:39 UTC
Note that there is no need to track stack depth independently in Perl if you use an array as your stack with the push and pop builtins: Perl will keep track of the array length, which is accessible either by using the array in scalar context or with the `$#` sigil. There is an important difference: `scalar @array` gives the number of elements in `@array` (`0` if `@array` is empty, `1` if there is one element) while `$#array` gives the highest index in `@array` (`-1` if `@array` is empty, `0` if there is one element).	[reply] [d/l] [select]

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Re^2: Matching nested parens
by jcb (Parson) on Oct 06, 2020 at 23:39 UTC

Note that there is no need to track stack depth independently in Perl if you use an array as your stack with the push and pop builtins: Perl will keep track of the array length, which is accessible either by using the array in scalar context or with the $# sigil. There is an important difference: scalar @array gives the number of elements in @array (0 if @array is empty, 1 if there is one element) while $#array gives the highest index in @array (-1 if @array is empty, 0 if there is one element).

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