Parsing parameters from command line with RegEx and PHP - 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
)