Ben Last wrote:
north_american_number_re = (RE().start
.literal('(').followed_by.exactly(3).digits.then.literal(')')
.then.one.literal("-").then.exactly(3).digits
.then.one.dash.followed_by.exactly(4).digits.then.end
.as_string())
Very cool. It's a bit verbose for my taste, and I'm not sure how well it will
cope with nested structure.
Here's my take on what readable regexps could look like:
north_american_number_re = RE.compile(r"""
^
"(" digit{3} ")" # And why shouldn't a regexp
"-" digit{3} # include en embedded comment?
"-" digit{4}
$
""")
The problem with Perl-style regexp notation isn't so much that it's terse - it's
that the syntax is irregular (sic) and doesn't follow modern principles for
lexical structure in computer languages. You can get a long way just by
ignoring whitespace, putting literals in quotes and allowing embedded comments.
Setting the re.VERBOSE flag achieves two out of three, so you can write:
north_american_number_re = RE.compile(r"""
^
( \d{3} ) # Definite improvement, though I really miss putting
- \d{3} # literals in quotes.
- \d{4}
$
""")
It's too bad re.VERBOSE isn't the default.
regards, Anders
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