fix recursion handling for empty expressions
fix recursion handling for empty expressions

svaarala/duktape,skomski/duktape,daimajia/duktape,kphillisjr/duktape,haosu1987/duktape,thurday/duktape,nivertech/duktape,thurday/duktape,zeropool/duktape,markand/duktape,daimajia/duktape,pombredanne/duktape,skomski/duktape,pombredanne/duktape,sloth4413/duktape,jmptrader/duktape,sloth4413/duktape,nivertech/duktape,zeropool/duktape,reqshark/duktape,reqshark/duktape,chenyaqiuqiu/duktape,harold-b/duktape,daimajia/duktape,eddieh/duktape,jmptrader/duktape,eddieh/duktape,pombredanne/duktape,haosu1987/duktape,reqshark/duktape,markand/duktape,sloth4413/duktape,tassmjau/duktape,tassmjau/duktape,jmptrader/duktape,jmptrader/duktape,nivertech/duktape,pombredanne/duktape,eddieh/duktape,harold-b/duktape,tassmjau/duktape,skomski/duktape,tassmjau/duktape,jmptrader/duktape,skomski/duktape,rwaldron/duktape,markand/duktape,reqshark/duktape,pombredanne/duktape,thurday/duktape,zeropool/duktape,pombredanne/duktape,eddieh/duktape,tassmjau/duktape,haosu1987/duktape,zeropool/duktape,eddieh/duktape,chenyaqiuqiu/duktape,haosu1987/duktape,skomski/duktape,zeropool/duktape,haosu1987/duktape,tassmjau/duktape,eddieh/duktape,kphillisjr/duktape,markand/duktape,harold-b/duktape,svaarala/duktape,haosu1987/duktape,rwaldron/duktape,reqshark/duktape,jmptrader/duktape,sloth4413/duktape,thurday/duktape,chenyaqiuqiu/duktape,skomski/duktape,tassmjau/duktape,harold-b/duktape,sloth4413/duktape,harold-b/duktape,jmptrader/duktape,eddieh/duktape,chenyaqiuqiu/duktape,svaarala/duktape,svaarala/duktape,nivertech/duktape,markand/duktape,chenyaqiuqiu/duktape,nivertech/duktape,daimajia/duktape,tassmjau/duktape,eddieh/duktape,thurday/duktape,thurday/duktape,reqshark/duktape,jmptrader/duktape,svaarala/duktape,rwaldron/duktape,chenyaqiuqiu/duktape,haosu1987/duktape,zeropool/duktape,haosu1987/duktape,svaarala/duktape,eddieh/duktape,pombredanne/duktape,markand/duktape,daimajia/duktape,markand/duktape,reqshark/duktape,zeropool/duktape,harold-b/duktape,markand/duktape,kphillisjr/duktape,harold-b/duktape,svaarala/duktape,rwaldron/duktape,skomski/duktape,zeropool/duktape,thurday/duktape,harold-b/duktape,daimajia/duktape,sloth4413/duktape,sloth4413/duktape,nivertech/duktape,nivertech/duktape,jmptrader/duktape,eddieh/duktape,rwaldron/duktape,skomski/duktape,harold-b/duktape,pombredanne/duktape,reqshark/duktape,kphillisjr/duktape,kphillisjr/duktape,reqshark/duktape,thurday/duktape,tassmjau/duktape,svaarala/duktape,haosu1987/duktape,kphillisjr/duktape,jmptrader/duktape,nivertech/duktape,rwaldron/duktape,tassmjau/duktape,sloth4413/duktape,kphillisjr/duktape,nivertech/duktape,chenyaqiuqiu/duktape,svaarala/duktape,nivertech/duktape,zeropool/duktape,pombredanne/duktape,kphillisjr/duktape,chenyaqiuqiu/duktape,markand/duktape,reqshark/duktape,thurday/duktape,haosu1987/duktape,thurday/duktape,harold-b/duktape,skomski/duktape,pombredanne/duktape,sloth4413/duktape,kphillisjr/duktape,chenyaqiuqiu/duktape,markand/duktape,zeropool/duktape,skomski/duktape,kphillisjr/duktape,chenyaqiuqiu/duktape,sloth4413/duktape