===========================
        DATA
        
patternAB = {
    sequence: [
        {zeroOrMore: 'a'},
        {text: 'b'},
    ]
}

mod sequence{
[
        mod zeroOrMore (text("a")),
        matcher text("b")
]
)


==========================
        HANDLERS

    case matcher:: mod sequence 
match = function(text, matcher) {
    loop fold(node-> matcher, 0->pos){
        n = match(matcher, mid(text, pos, length(text))).// <-- every time length?
        
        if (pos == pos_FAIL || n == pos_FAIL){
            pos_FAIL:: break
        } else {
            pos+n
        }
    }
}

    case matcher:: mod zeroOrMore (Dereferenced)
match= function(text, matcher){
    matcherChild = matcher:: Dereferenced.               //<---         extract child(unification)
    
    loop fold inf(0->pos, n==pos_FAIL){                              //<---         infinite loop?
        n = match(matcherChild, mid(text, pos, length(text))).
        
        if (n == pos_FAIL:: break){
            pos
            
        } else {
            pos+n
        }
    }
}

    case matcher:: matcher text
match = function(text, matcher) {
    pattern = matcher:: string. 
    
    if (length(text)>0 &&
        length(pattern) <= length(text) &&
        mid(text, 0, length(pattern)) == pattern)
    {
        length(pattern);
        
    } else {
        pos_FAIL;
    }
}

match = function(text::string, pattern::string)::string{
     n= match(pattern, text).
     
     if (n != pos_FAIL)
        {mid(text, 0, n)}
    else 
        {text_FAIL}
}

=================================
    CLIENT
    
test = function(){
    match(patternAB, "aaaaab").
    match(patternAB, "baaaaa").
}