Select a regexp YAML block

Question

I have a large YAML file and I want to select the whole node using regex. For instance:

Node1: Child: GrandChild: foo Node2: AnotherChild: AnotherGrandChild: bar Node3: LastChild: LastGrandChild: foo 

How can I use a regex to select all Node2 in the above example and return:

 Node2: AnotherChild: AnotherGrandChild: bar 

Answer 1

Since everything else in this node is indented (if I understand YAML correctly), this works, at least in your example line:

 $mask = '~(^%s:\n(?:^[ ].*\n?)*$)~m'; $pattern = sprintf($mask, 'Node2'); $r = preg_match($pattern, $yaml, $matches); $node = reset($matches); 

At least on my computer. I wanted to make a demo version of the code, but this gives an error. Will check for regex.

Fully bloated:

 $yaml = <<<EOD Node1: Child: GrandChild: foo Node2: AnotherChild: AnotherGrandChild: bar Node3: LastChild: LastGrandChild: foo EOD; $mask = '~ ( # start matching group ^ # a node start always at the beginning of a line %s: # placeholder for sprintf for the nodname + : $ # end of line for the nodename \n (?: # non-matching group to hold all subsequent, indented lines ^ # beginning of sublines (?:[ ]{2})+ # indentation is required, always a muliple of two spaces, non matching group .*\n? # match anything else on that subsequent line, optionally the newline character )* # 0 or more subsequent, indented lines )$ # this ends a line, to not take over the newline of the last subsequent line (see \n? above). # the following are modifiers: # m - pcre multiline modifier (in php same as in perl) # x - to allow spaces and the comments all over here ;) ~mx '; $pattern = sprintf($mask, 'Node2'); $r = preg_match($pattern, $yaml, $matches); $node = reset($matches); var_dump($node); 

Answer 2

You might want to use a library like php-yaml .