void testline(real y) {
 draw((0,y)--(100,y),currentpen+solid);
 draw((0,y-10)--(100,y-10),currentpen+dotted);
 draw((0,y-20)--(100,y-20),currentpen+dashed);
 draw((0,y-30)--(100,y-30),currentpen+longdashed);
 draw((0,y-40)--(100,y-40),currentpen+dashdotted);
 draw((0,y-50)--(100,y-50),currentpen+longdashdotted);
 draw((0,y-60)--(100,y-60),currentpen+Dotted);
}

currentpen=linewidth(0.5);
testline(100);