Question

I want to get values of command tags (GET, FROM, IN, etc.) My command is:

// My command
$_cmd = 'GET a, b FROM p IN a and c="I am from Sarajevo" or d>1 ';

// My parser
if(preg_match_all('/(GET|FROM|IN)\s+([^\s]+)/si',$_cmd, $m))
    $cmd = array_combine($m[1], $m[2]);

Output:

Array
(
  [GET] => a,
  [FROM] => p
  [IN] => a
  [from] => Sarajevo"
)

I am looking for this output:

Array
(
  [GET] => a, b
  [FROM] => p
  [IN] => a and c="I am from Sarajevo" or d>1
)

As you see, problem is with whitespaces and repeated command tags in strings (like from). So how can I parse this command?

Answer 1

You cannot easily parse that with a single regex. (It’s doable, but not simple.)

You should use a simple tokenizer, where a regex again becomes a useful tool:

  preg_match_all('/\w+|".*?"|\W/', $_cmd = 'GET a, b FROM p IN a and c="I am from Sarajevo" or d>1 ', $list);

This gives you a simple list, where you just have to find the clauses that you are interested in, then remerge the subsequent tokens (though I’m confused about your use case):

[0] => Array
    (
        [0] => GET
        [1] => a
        [2] => ,
        [3] => b
        [4] => FROM
        [5] => p
        [6] => IN
        [7] => a
        [8] => and
        [9] => c
        [10] => =
        [11] => "I am from Sarajevo"
        [12] => or
        [13] => d
        [14] => >
        [15] => 1
    )