18. A computer program product comprising one or more hardware computer memories having stored thereon computer executable instructions that are structured such that, when executed by at least one or more processors, the computer executable instructions cause at least one of the one or more processors to perform the following: at a first domain, the first domain configured to request and receive data using a first dialect, access an expression tree comprising a plurality of nested expressions, the plurality of nested expressions spanning a plurality of domains and including: (i) one or more first nested expressions that are expressed in the first dialect in a manner that they are expandable to a second dialect of a second domain for evaluation by the second domain, and (ii) one or more second nested expressions that are expressed in the first dialect in a manner that they are expandable to a third dialect of a third domain for evaluation by the third domain, wherein the first dialect, the second dialect, and the third dialect are each different from each other, and wherein the expression tree contains all information needed to expand the one or more first nested expressions from the first dialect to the second dialect and contains all information needed to expand the one or more second nested expressions from the first dialect to the third dialect; determine that the one or more first expressions are to be evaluated by the second domain, and that the one or more second expressions are to be evaluated by the third domain; and based at least on determining that the one or more first expressions and the one or more second expressions are to evaluated by the second and third domains, respectively, expand the one or more first expressions to the second dialect, and expand the one or more second expressions to the third dialect.
18. A computer program product comprising one or more hardware computer memories having stored thereon computer executable instructions that are structured such that, when executed by at least one or more processors, the computer executable instructions cause at least one of the one or more processors to perform the following: at a first domain, the first domain configured to request and receive data using a first dialect, access an expression tree comprising a plurality of nested expressions, the plurality of nested expressions spanning a plurality of domains and including: (i) one or more first nested expressions that are expressed in the first dialect in a manner that they are expandable to a second dialect of a second domain for evaluation by the second domain, and (ii) one or more second nested expressions that are expressed in the first dialect in a manner that they are expandable to a third dialect of a third domain for evaluation by the third domain, wherein the first dialect, the second dialect, and the third dialect are each different from each other, and wherein the expression tree contains all information needed to expand the one or more first nested expressions from the first dialect to the second dialect and contains all information needed to expand the one or more second nested expressions from the first dialect to the third dialect; determine that the one or more first expressions are to be evaluated by the second domain, and that the one or more second expressions are to be evaluated by the third domain; and based at least on determining that the one or more first expressions and the one or more second expressions are to evaluated by the second and third domains, respectively, expand the one or more first expressions to the second dialect, and expand the one or more second expressions to the third dialect. 20. The computer program product of claim 18 , wherein expanding the one or more first expressions to be evaluated by the second comprises using an expansion call internal to the common format.