Python-Why does PHP's ' preg ' require a regular delimiter?

Is it because of a study with Perl? But Perl is the language of inline regular expressions, and it is natural to use delimiters to indicate the regular. Since PHP is used pregSeries function processing, why do you use separators?

Python is also treated with a function ( re provided by the module) and does not require delimiters.

pattern = re.compile("foo")

As in Haskell, Text.Regex.Posix separators are not required.

"my left foot" =~ "foo" :: Bool

Interestingly, the series functions that began to be deprecated in PHP 5.3 ereg are non-delimited:

eregi("(ozilla.[23]|MSIE.3)", $_SERVER["HTTP_USER_AGENT"]);

So preg what is the purpose of a series of functions that are designed to be pattern-delimited?

Reply content:

Is it because of a study with Perl? But Perl is the language of inline regular expressions, and it is natural to use delimiters to indicate the regular. Since PHP is processed with a preg series of functions, why use separators?

Python is also treated with a function ( re provided by the module) and does not require delimiters.

pattern = re.compile("foo")

As in Haskell, Text.Regex.Posix separators are not required.

"my left foot" =~ "foo" :: Bool

Interestingly, the series functions that began to be deprecated in PHP 5.3 ereg are non-delimited:

eregi("(ozilla.[23]|MSIE.3)", $_SERVER["HTTP_USER_AGENT"]);

So preg what is the purpose of a series of functions that are designed to be pattern-delimited?

If you add a delimiter, you can add some pattern modifiers,, and so on, how do you m u i s add delimiters? And the preg series of words is the lineage PCRE series, so follow PCRE the basic rules, it POSIX is not the delimiter. The other preg series and perl a little different, so should not follow perl the study it.

Resources:
The difference between Pcre and Perl
The difference between pcre and POSIX regularization
Pattern modifiers available in regular expressions

