nl_tokens: This is where the action is .
pl_tokens: function runmath ( s ) { var ans ; try { // We want to catch parse errors and die appropriately // Make a parser and feed the input ans = new nearley . Parser ( grammar . ParserRules , grammar . ParserStart ) . feed ( s ) ; // Check if there are any results if ( ans . results . length ) { return ans . results [ 0 ] . toString ( ) ; } else { // This means the input is incomplete. var out = "Error: incomplete input, parse failed. :(" ; return out ; } } catch ( e ) { // Panic in style, by graphically pointing out the error location. var <mask> = new Array ( PROMPT . length + e . offset + 1 ) . join ( "-" ) + "^  Error." ; //                                  -------- //                                         ^ This comes from nearley! return out ; } }