[attrname := ] EVALUATE(expression) ;
[attrname := ] EVALUATE(module [, defname ] ) ;
| attrname | Optional. The action name, which turns the action into a definition, therefore not executed until the attrname is used as an action. |
| expression | The function to call in an action context. |
| module | The module to evaluate. |
| defname | Optional. The name of a specific definition within the module to evaluate. If omitted, all definitions in the module are evaluated. |
The first form of the EVALUATE action names an expression (typically a function call) to execute in an action context. This is mainly useful for calling functions that have side-effects, where you don't care about the return value.
The second form of the EVALUATE action recursively expands the exported definitions of the module and evaluates them. If a defname is specified, then only that definition is evaluated.
Example:
Form 1 example:
myService := SERVICE
UNSIGNED4 doSomething(STRING text);
END;
ds := DATASET('MyFile', {STRING20 text} , THOR);
APPLY(ds, EVALUATE(doSomething(ds.text)));
//calls the doSomething function once for each record in the ds
// dataset, ignoring the returned values from the function
Form 2 example:
M := MODULE
EXPORT a := OUTPUT(10);
EXPORT b := OUTPUT('Hello');
END;
M2 := MODULE
EXPORT mx := M;
EXPORT d := OUTPUT('Richard');
END;
EVALUATE(M2);
//produces three results:
// Result_1: 10
// Result_2: Hello
// Result_3: RichardSee Also: APPLY, SERVICE Structure,