code: function parseFnKeyConst( str_ , runtime ) {
  	var separatorIndex = nextSeparator( str_ , runtime ) ;
  
  	var str = str_.slice( runtime.i , separatorIndex ) ;
  	//console.log( 'str before:' , str_ ) ;
  	//console.log( 'str after:' , str ) ;
  
  	//var indexOf ;
  	//str = str.slice( runtime.i , runtime.iEndOfLine ) ;
  	//if ( ( indexOf = str.indexOf( ' ' ) ) !== -1 ) { str = str.slice( 0 , indexOf ) ; }
  
  	runtime.i += str.length ;
  
  	if (
  		str_[ separatorIndex ] === ':' ||
  		( str_[ separatorIndex ] === ' ' && afterSpacesChar( str_ , runtime , separatorIndex ) === ':' )
  	) {
  		// This is a key, return the unquoted string
  		return str ;
  	}
  	else if ( str in common.constants ) {
  		return common.constants[ str ] ;
  	}
  	else if ( fnOperators[ str ] ) {
  		return fnOperators[ str ] ;
  	}
  	else if ( str in expressionConstants ) {
  		return expressionConstants[ str ] ;
  	}
  	else if ( runtime.operators[ str ] ) {
  		return runtime.operators[ str ] ;
  	}
  	else if ( str in runtime.constants ) {
  		return runtime.constants[ str ] ;
  	}
  
  	throw new SyntaxError( "Unexpected '" + str + "' in expression" ) ;
  }
docs: An identifier that is a function, a key or a constant