The Python “PRegEx - Programmable Regular Expressions” is a cool way of thinking about the problem. I haven’t tried it yet.
Here’s a regex for parsing a .com or .org URL:
from pregex.core.classes import AnyLetter, AnyDigit, AnyFrom
from pregex.core.quantifiers import Optional, AtLeastAtMost
from pregex.core.operators import Either
from pregex.core.groups import Capture
from pregex.core.pre import Pregex
http_protocol = Optional('http' + Optional('s') + '://')
www = Optional('www.')
alphanum = AnyLetter() | AnyDigit()
domain_name = \
alphanum + \
AtLeastAtMost(alphanum | AnyFrom('-', '.'), n=1, m=61) + \
alphanum
tld = '.' + Either('com', 'org')
ip_octet = AnyDigit().at_least_at_most(n=1, m=3)
port_number = (AnyDigit() - '0') + 3 * AnyDigit()
# Combine sub-patterns together.
pre: Pregex = \
http_protocol + \
Either(
www + Capture(domain_name) + tld,
3 * (ip_octet + '.') + ip_octet + ':' + port_number
)
Fetching the resulting Pregex instance’s underlying RegEx pattern.
regex = pre.get_pattern()
This is the RegEx pattern that the above method returns.
(?:https?\:\/\/)?(?:www\.)?(?:[0-9\.]+\:[0-9]{4}|([^\r\:\n\x0c\\ \t\x0b]+)(?:\.com|\.org))
