On 01/30/10 13:35, Larry Evans wrote:
On 01/30/10 00:37, Hicham Mouline wrote:
Hello,
struct params { double field1; double field2; double field3; double fiedl4; };
I would like to generate all the types that hold any combination of the members of params. [snip]
Step1: Create cross-product of void and {field1,field2,...}. This will produce a sequence of pairs:
no_yes = ( (void,field1) , (void,field2) ... , (void,fieldn) )
Step2:
Create the crosss product of all rows in no_yes.
cross_no_yes = ( (void,void,..void) , (field1,void,...void) , (void,field2,void...,void) ... , (field1,field2,...fieldn) )
step3:
remove all the voids in all the rows of cross_no_yes.
Since the size
== n and each element in that row is size 2, the cross_no_yes size would be 2^n. Then simply rm the all void row. Not tested. Now tested. The attached produces:
/home/evansl/prog_dev/boost-svn/ro/trunk/sandbox-local/build/gcc4_4v/sandbox/variadic_templates/libs/mpl/sandbox/list_comprehension~subsets.exe
absent_fields_seq=
( Absent=9000, Field=9001)
( Absent=9000, Field=9002)
( Absent=9000, Field=9003)
size