Parsing parameters from command line with RegEx and PHP

Question

I have this as an input to my command line interface as parameters to the executable:

-Parameter1=1234 -Parameter2=38518 -param3 "Test \"escaped\"" -param4 10 -param5 0 -param6 "TT" -param7 "Seven" -param8 "secret" "-SuperParam9=4857?--SuperParam10=123"

What I want to is to get all of the parameters in a key-value / associative array with PHP like this:

$result = [
    'Parameter1' => '1234',
    'Parameter2' => '1234',
    'param3' => 'Test \"escaped\"',
    'param4' => '10',
    'param5' => '0',
    'param6' => 'TT',
    'param7' => 'Seven',
    'param8' => 'secret',
    'SuperParam9' => '4857',
    'SuperParam10' => '123',
];

The problem here lies at the following:

• parameter's prefix can be - or --
• parameter's glue (value assignment operator) can be either an = sign or a whitespace ' '
• some parameters may be inside a quote block and can also have different, both separators and glues and prefixes, ie. a ? mark for the separator.

So far, since I'm really bad with RegEx, and still learning it, is this:

/(-[a-zA-Z]+)/gui

With which I can get all the parameters starting with an - ...

I can go to manually explode the entire thing and parse it manually, but there are way too many contingencies to think about.

Answer 1

You can try this that uses the branch reset feature (?|...|...) to deal with the different possible formats of the values:

$str = '-Parameter1=1234 -Parameter2=38518 -param3 "Test \"escaped\"" -param4 10 -param5 0 -param6 "TT" -param7 "Seven" -param8 "secret" "-SuperParam9=4857?--SuperParam10=123"';

$pattern = '~ --?(?<key> [^= ]+ ) [ =]
(?|
    " (?<value> [^\\\\"]*+ (?s:\\\\.[^\\\\"]*)*+ ) "
  |
    ([^ ?"]*)
)~x';

preg_match_all ($pattern, $str, $matches);
$result = array_combine($matches['key'], $matches['value']);
print_r($result);

demo

In a branch reset group, the capture groups have the same number or the same name in each branch of the alternation.

This means that (?<value> [^\\\\\\\\"]*+ (?s:\\\\\\\\.[^\\\\\\\\"]*)*+ ) is (obviously) the value named capture, but that ([^ ?"]*) is also the value named capture.

Answer 2

You could use

--?
(?P<key>\w+)
(?|
    =(?P<value>[^-\s?"]+)
    |
    \h+"(?P<value>.*?)(?<!\\)"
    |
    \h+(?P<value>\H+)
)

See a demo on regex101.com .

---

Which in PHP would be:

 <?php $data = <<<DATA -Parameter1=1234 -Parameter2=38518 -param3 "Test \\"escaped\\"" -param4 10 -param5 0 -param6 "TT" -param7 "Seven" -param8 "secret" "-SuperParam9=4857?--SuperParam10=123" DATA; $regex = '~ --? (?P<key>\\w+) (?| =(?P<value>[^-\\s?"]+) | \\h+"(?P<value>.*?)(?<!\\\\\\\\)" | \\h+(?P<value>\\H+) )~x'; if (preg_match_all($regex, $data, $matches)) { $result = array_combine($matches['key'], $matches['value']); print_r($result); } ?> 

---

This yields

 Array ( [Parameter1] => 1234 [Parameter2] => 38518 [param3] => Test \\"escaped\\" [param4] => 10 [param5] => 0 [param6] => TT [param7] => Seven [param8] => secret [SuperParam9] => 4857 [SuperParam10] => 123 )