Splitting a string with Swift using a PHP-equivalent regular expression (#\n\s*\n#Uis)

Question

I need to split a given multi-line string (sample here) using a regular expression with Swift. With PHP (the language I use for building web applications) I do this (after removing comments and substituting some tokens):

// split the file contents in fragments
$fragments = preg_split("#\n\s*\n#Uis", $contents);

And this is what I get if execute preg_split over the code sample:

Array
(
    ...
    [2] => 
CREATE TABLE IF NOT EXISTS c_search_history (
    entry_id BIGINT(64) UNSIGNED NOT NULL AUTO_INCREMENT,
    entry_date_added DATETIME NOT NULL,
    entry_language CHAR(2) NOT NULL DEFAULT 'es',
    entry_query TEXT NOT NULL,
    PRIMARY KEY (entry_id),
    INDEX (entry_date_added),
    INDEX (entry_language)
) ENGINE=InnoDB DEFAULT CHARSET utf8mb4 COLLATE utf8mb4_unicode_520_ci;
    [3] => 
CREATE TABLE IF NOT EXISTS c_search_weight_entries (
    entry_id BIGINT(64) UNSIGNED NOT NULL AUTO_INCREMENT,
    entry_date DATETIME NOT NULL,
    entry_model VARCHAR(175) NOT NULL,
    entry_model_id BIGINT(64) UNSIGNED NOT NULL,
    entry_value DOUBLE NOT NULL,
    PRIMARY KEY (entry_id),
    INDEX (entry_date),
    INDEX (entry_model),
    INDEX (entry_model_id),
    INDEX (entry_value)
) ENGINE=InnoDB DEFAULT CHARSET utf8mb4 COLLATE utf8mb4_unicode_520_ci;
...
)

The goal for this is to take an .sql file and flatten its contents so each function, table, procedure, trigger or view definition becomes a one-liner for later execution. The problem is I'm fairly new to Swift and I haven't been able to translate the #\n\s*\n#Uis regular expression into something usable for NSRegularExpression.

I tried to use this solution but it outputs nothing for me (but I may be that I have used it in the wrong way or I don't understand how it really works).

Can you give me a hint? Any help would be greatly appreciated :)

Does this answer your question? [How to do do regex search on multiple lines?](https://stackoverflow.com/questions/57006333/how-to-do-do-regex-search-on-multiple-lines) — Joakim Danielson, May 31 '20 at 11:40

score 0 · Answer 1 · answered May 31 '20 at 19:31

After doing, undoing and trying different approaches, seems the only thing I needed to do was to substitute #\n\s*\n#Uis with \\n\\s*\\n and it worked. I still need to do some serious research on NSRegularExpression and a lot of other Swift concepts but, for now, that did the trick :)

Splitting a string with Swift using a PHP-equivalent regular expression (#\n\s*\n#Uis)

1 Answers1