nl_tokens: / * Since JavaScript provides no convenient way to determine if a character is in a particular Unicode category we use metacircularity to accomplish this ( oh yeaaaah! )
pl_tokens: function isValidIdentifierChar ( ch , first ) { // check directly for ASCII if ( ch <= "\u007F" ) { if ( ( ch >= 'a' && ch <= 'z' ) || ( ch >= 'A' && ch <= 'Z' ) || ch === '$' || ch === '_' || ( ! first && ( ch >= '0' && ch <= '9' ) ) ) { return true ; } return false ; } // create an object to test this in var x = { } ; x [ "x" + ch ] = true ; x [ ch ] = true ; // then use eval to determine if it's a valid character var valid = false ; try { <mask> = ( Function ( "x" , "return (x." + ( first ? "" : "x" ) + ch + ");" ) ( x ) === true ) ; } catch ( ex ) { } return valid ; }