n=10
d=[0,1,0,0]
while(n<10000){println n;d[0]+=1;if(d[0]>=d[1]){d[0]=0;d[1]+=1};if(d[2]!=0&&d[1]>=d[2]||d[1]>9){d[0]=0;d[1]=1;d[2]+=1;if(d[2]<2){d[2]=2}};if(d[3]!=0&&d[2]>=d[3]||d[2]>9){d[0]=0;d[1]=1;d[2]=2;d[3]+=1;if(d[3]<3){d[3]=3}};n=d[3]*1000+d[2]*100+d[1]*10+d[0]}
Note that non-ascii characters in the above source code will be escaped (such as \x9f).