SAS and text pointers - not reading all values -

data test;     infile datalines missover;     input @ "r1" r1           @ "r2" r2           @ "r3" r3           @ "r4" r4;     datalines;     r4 34 r2 21 r3    r1 12     r4 12 r2 19 r3    r1 76     ; run; 

why in test data set values of r1 , rest .?

my desired output is:

r1    r2    r3    r4 -------------------- 12    21    .     34 76    19    .     12 

after reading example in sas documentation found solution:

data test;     infile datalines missover;     input @'r1' r1           @1 @'r2' r2           @1 @'r3' r3           @1 @'r4' r4;     datalines;     r4 34 r2 21 r3    r1 12     r4 12 r2 19 r3    r1 76     ; run; 

it needed go beginnig of line @1 because without sas keeps searching given strings last pointer location.