options ls=95  nodate;
data diets;
   /* ADDITIVE is either A or B (or none for control) */
   /* AMOUNT is either 1 or 2 (or none for control) */
   length trt $19.;
   input trt $ wtgain;
   cards; 
Control 4.1
Control 3.3
Control 3.1
Control 4.2
Control 3.6
Control 4.4
Control+level-1-A 5.2
Control+level-1-A 4.8
Control+level-1-A 4.5
Control+level-1-A 6.8
Control+level-1-A 5.5
Control+level-1-A 6.2
Control+level-2-A 6.3
Control+level-2-A 6.5
Control+level-2-A 7.2
Control+level-2-A 7.4
Control+level-2-A 7.8
Control+level-2-A 6.7
Control+level-1-B 6.5
Control+level-1-B 6.8
Control+level-1-B 7.3
Control+level-1-B 7.5
Control+level-1-B 6.9
Control+level-1-B 7
Control+level-2-B 9.5
Control+level-2-B 9.6
Control+level-2-B 9.2
Control+level-2-B 9.1
Control+level-2-B 9.8
Control+level-2-B 9.1
run;

proc glm;
   class trt; /*watch ordering in CLASS LEVEL INFO in output*/
   model wtgain=trt;
   contrast "theta_a:control - avg(others)" trt 4 -1 -1 -1 -1;
   contrast "theta_b:(A-B)_1 - (A-B)_2" trt 0 1 -1 -1 1;
   contrast "theta_c:A-B" trt 0 1 -1 1 -1;
   contrast "theta_c:1-2" trt 0 1 1 -1 -1;
   contrast "all 4" 
    trt 4 -1 -1 -1 -1, 
    trt 0 1 -1 -1 1, 
    trt 0 1 -1 1 -1, 
    trt 0 1 1 -1 -1;
   contrast "A-B at level 1" trt 0 1 0 -1 0; 
   contrast "A-B at level 2" trt 0 0 1 0 -1;  
   contrast "2 simple A-B effects" 
    trt 0 1 0 -1 0, trt 0 0 1 0 -1;  
run;