Plain Code

<?php
$STATES = array("WAIT","SCOPE","CRITERIA","ITEM","QUOTE");
function debug_this($value)
{
    echo $value;
}
function is_escaped($escape_index,$current_index)
{
    return ($escape_index != -1 && $escape_index == ($current_index - 1));
}
function add_and_reset_scope(&$context, &$scope,&$criteria = array())
{
    if (isset($context[$scope]) && is_array($context[$scope])) $criteria = array_merge($criteria,$context[$scope]);
    $context[$scope] = $criteria;
    $criteria = array();
    $scope = "";
}
function add_new_criteria(&$criteria,$initial_character)
{
    $criteria[] = $initial_character;
    debug_this( "\10\tNEW CRITERIA BEGINS: " . $criteria[count($criteria) - 1] . "\n");
}
function add_to_current_criteria(&$criteria,$value){
    $last = count($criteria) - 1;
    $criteria[$last] .= $value;
    debug_this("\10\tCURRENT: " . $criteria[$last] . "\n");
}
function setState(&$state,$newState,$line = -1) {
    global $STATES; $out = "[$line]: STATE ";
    if(isset($state)) if (isset($STATES[($index = log($state,2))])) $out .= $STATES[$index]. "($state)";
        else $out .=  "\"$state\"";
    else $out .= "NULL";
    $out .= ", CHANGING TO " . $STATES[log($newState,2)] . "($newState)\n";
    debug_this($out);
    $state = $newState;
}
function BBranch($branch,$state,$value,$line = -1)
{
    global $STATES;
    debug_this("[$line] BRANCH {$branch} [" . $STATES[log($state,2)] . "]: $value \n" ); 
}

function parse($str,$default_scope = 'group'){
    //states
    global $STATES;
    
    foreach ($STATES as $INDEX => $STATENAME) { 
        $$STATENAME = pow(2,$INDEX); 
        debug_this($STATENAME . " = " . $$STATENAME . "\n");
    }
    debug_this("\$WAIT = $WAIT\n");
    $ERRORS = array();
    $escape = -1;
    $context = array();
    $criteria = array();
    $quote = $item = $scope = "";
    setState($state,($pre_quote_state = $WAIT),__LINE__);
    $str .= " ";
    foreach (str_split($str) as $index => $value)
    {
        if ($state > $QUOTE) setState($state,$WAIT,__LINE__);
        if(preg_match("/\s/",$value)){
        BBranch('WHITESPACE',$state,$value,__LINE__);
            if($state == $ITEM)
            {
                if (is_escaped($escape,$index)) $item .= $value;
                else {
                    add_to_current_criteria($criteria,"",__LINE__);
                    if(count($scope)) add_and_reset_scope($context,$scope,$criteria);                        
                    setState($state,$WAIT,__LINE__);
                }
            }
            elseif($state == $QUOTE)
            {
                add_to_current_criteria($criteria,$value);
            }
            elseif($state == $SCOPE)
            {
                if($default_scope != ""){
                    add_new_criteria($criteria,$scope);
                    add_and_reset_scope($context,$default_scope,$criteria);
                    setState($state,$WAIT,__LINE__);
                }
                else add_and_reset_scope($context,$scope);
                setState($state,$WAIT,__LINE__);
            }
        }
        elseif(preg_match("/[\:\=]/",$value)) {
            BBranch('EQUIV',$state,$value,__LINE__);
            if($state == $SCOPE && strlen($scope)) {
                //add_and_reset_scope($context,$scope);
                setState($state,$CRITERIA,__LINE__);
            }
            elseif($state & ( $ITEM | $QUOTE )) add_to_current_criteria($criteria,$value);
        }
        elseif(strstr("\\",$value)){
            BBranch('ESCAPE',$state,$value,__LINE__);
            if (! is_escaped($escape,$index)) $escape = $index;
            else {
                if($state & ( $ITEM | $QUOTE )) {
                    add_to_current_criteria($criteria,$value);
                }
                if($state & $CRITERIA)
                {
                    add_new_criteria($criteria,$value);
                    setState($state,$ITEM);
                }
            }
        }
        elseif(strstr(",",$value)){
            BBranch('COMMA',$state,$value,__LINE__); 
            if($state == $ITEM)
            {
                setState($state,$CRITERIA,__LINE__);
            }
            elseif($state == $SCOPE)
            {
                add_new_criteria($criteria,$scope);
                if($default_scope != ""){
                    $scope = $default_scope;
                    setState($state,$CRITERIA,__LINE__);
                }
                else {
                    add_and_reset_scope($context,$scope = null,$criteria);
                    $ERRORS[] = "UNEXPECTED T_COMMA ENCOUNTERED <INDEX: $Index>";
                    setState($state,$WAIT,__LINE__);
                }
            }
            elseif($state & ( $CRITERIA | $WAIT)) $ERRORS[] = "UNEXPECTED T_COMMA ENCOUNTERED <INDEX: $Index>";
            
        }
        elseif(preg_match("/[\"']/",$value)){
            BBranch('QUOTE',$state,$value,__LINE__);
            
            if($state == $QUOTE){
                debug_this("IS QUOTE ESCAPED: " . ((is_escaped($escape,$index)) ? "YES" : "NO") . "\n");
                if ($value == $quote && !is_escaped($escape,$index))
                {
                    
                    setState($state,$pre_quote_state,__LINE__);
                    $quote = "";
                }
                elseif($pre_quote_state & ( $CRITERIA | $ITEM))
                {
                    add_to_current_criteria($criteria,$value);
                }
                elseif($pre_quote_state & ( $WAIT | $SCOPE ))
                {
                    $scope .= $value;
                }
            }
            elseif($state & ( $WAIT | $CRITERIA ))
            {
                $pre_quote_state = $state;
                $quote = $value;
                setState($state,$QUOTE,__LINE__);
            }
        }
        else {
            BBranch('WORD',$state,$value,__LINE__);
            if($state == $WAIT) {
                
                setState($state,$SCOPE,__LINE__);
                $scope = $value;
            }
            elseif($state == $SCOPE) $scope .= $value;
            elseif ($state == $CRITERIA)
            {
                setState($state,$ITEM,__LINE__);
                add_new_criteria($criteria,$value);
            }
            elseif ($state == $ITEM) add_to_current_criteria($criteria,$value);
            elseif($state == $QUOTE){
                
                if($pre_quote_state == $WAIT){
                    
                    $pre_quote_state = $SCOPE;
                    $scope = $value;
                }
                elseif($pre_quote_state == $CRITERIA) {
                    
                    $pre_quote_state = $ITEM;
                    add_new_criteria($criteria,$value);
                }
                else
                {
                    add_to_current_criteria($criteria,$value);
                }
            }
                
        }
    }
    return $context;
}
function interpret($arr){
    $str = "";
    $str = print_r($arr,true);
    return $str;
}

$strs = array(
    "file:hello.fa start:0 end:1322251",
    "file:hello.fa group:\"wild dogs\"",
    "file:hello.fa group:\"12 angry men\" group:\"11 'angry' men\"",
    "file:hello.fa group:\"12 angry men\",\"11 \\\"angry\\\" men\""

);
foreach ($strs as $search){
    echo $search . ":\n " . str_replace("\n", "\n\t", interpret(parse($search))). "\n";
}