Hi Eric, (Apologies in advance for such a stupid question.) I'm building a fairly simple parser using xpressive. I need to parse text like this: node C91967 { label = "What brand of coffee do you use?"; position = (100 280); states = ("Columbian blend" "Columbian gold" "Columbian all star" "Columbian cinnamon"); HR_Inaccuracy = "0"; HR_Risk = "0"; HR_Time = "1"; HR_RefKey = ""; HR_Desc = "Question"; HR_ID = "91967"; HR_Def = "<div align=\"left\"> </div><br/>"; HR_Web_Page = ""; HR_Type2 = "3"; } potential (C91976 | CXXX) { data = ( 0 1 % Coffee type not to your taste 0 1 % Discount coffee 0.98 0.02 % Low quality coffee filter 0 1 % Low water quality 0 1 % Old coffee machine 0 1 % Used coffee filter 0 1 % Water coffee mixture incorrect 0 1 ); % Other Problem } There are multiple nodes or potential in the files, so my final regex looks something like netFile = modelConfiguration >> causeNode >> actions >> optional( questions ) >> causeProbabilities >> actionProbabilities; I then make one regex to parse a single potential, and wrap that regex in another so I can look for a list of those potentials: sregex row = *space >> _float[push_back(ref(actionProbs),as<Float>(_))] >> space >> -*_ >> _ln; actionPotential = -*_ >> "potential (C" >> -*_ >> "data = (" >> +row >> -*_ >> '}'; actionProbabilities = +( *space >> actionPotential ); Now my problem is that I get a stack overflow very easily if the 'row' regex is too long. In factm I have to remove the latter ">> space" from 'row' to not get a stack overflow. Am I using the library in a fundamentally wrong way? If so, how can I try to fix it? best regards -Thorsten