5. A computer-implemented process for performing string transformations involving at least two different operations, comprising: using a computer to perform the following process actions: accessing a first expression language associated with string transformations that involve a first operation, said first expression language comprising a first set of grammar rules defining expressions therein; accessing a second expression language associated with string transformations that involve at least one operation that is different from said first operation, said second expression language comprising a second set of grammar rules defining expressions therein; combining the first expression language and the second expression language to establish a combined expression language; generating a synthesis procedure which learns a set of expressions in the combined expression language that produces a prescribed output from one or more input string variables using said at least two different operations based on a set of one or more input-output examples each comprising one or more input string variables and said prescribed output; and receiving one or more input string variables of a same type found in the set of one or more input-output examples, and producing the prescribed output using the synthesis procedure.
5. A computer-implemented process for performing string transformations involving at least two different operations, comprising: using a computer to perform the following process actions: accessing a first expression language associated with string transformations that involve a first operation, said first expression language comprising a first set of grammar rules defining expressions therein; accessing a second expression language associated with string transformations that involve at least one operation that is different from said first operation, said second expression language comprising a second set of grammar rules defining expressions therein; combining the first expression language and the second expression language to establish a combined expression language; generating a synthesis procedure which learns a set of expressions in the combined expression language that produces a prescribed output from one or more input string variables using said at least two different operations based on a set of one or more input-output examples each comprising one or more input string variables and said prescribed output; and receiving one or more input string variables of a same type found in the set of one or more input-output examples, and producing the prescribed output using the synthesis procedure. 9. The process of claim 5 , wherein there are a plurality of input-output example, and wherein the process action of generating a synthesis procedure, comprises the actions of: (a) selecting a previously unselected input-output example; (b) employing a string generation procedure to compute a set of expressions in the combined expression language that produce the prescribed output of the currently selected input-output example from the one or more input string variables of the currently selected input-output example using said first operation and said at least one operation that is different from said first operation; (c) representing the computed set of expressions using a prescribed combined expression language data structure; (d) repeating actions (a) through (c) to produce another computed set of expressions represented using the prescribed combined expression language data structure; (e) employing an intersect procedure to intersect the computed sets of expressions, as represented by the prescribed combined expression language data structure, wherein the resulting intersected sets of expressions are also represented by the prescribed combined expression language data structure; (f) determining if there is at least one previously unselected input-output example remaining; (g) wherever it is determined that there is at least one previously unselected input-output example remaining, repeating actions (a) through (c) to produce another computed set of expressions represented using the prescribed combined expression language data structure, employing said intersect procedure to intersect the last computed set of expressions, as represented by the prescribed combined expression language data structure, with the last produced intersected sets of expressions, wherein the resulting intersected sets of expressions are also represented by the prescribed combined expression language data structure; and (h) repeating actions (f) and (g) until there are no more previously unselected input-output example remaining.