Difference between revisions of "Agent Calls"
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Whenever an agent is created with a closed target, the actual '''agent callee''' is calculated at '''agent creation''' time. | Whenever an agent is created with a closed target, the actual '''agent callee''' is calculated at '''agent creation''' time. | ||
*Two wrappers are generated: | *Two wrappers are generated: | ||
− | **one which expects the closed arguments as a tuple (encapsulated | + | **one which expects the closed arguments as a tuple (encapsulated). The only difference to the frozen wrapper is how the '''agent callee''' is calculated. |
**and one that expects them as separate parameters. | **and one that expects them as separate parameters. |
Revision as of 16:55, 21 August 2006
Work in progress!
Terminology
In the following text the place where an agent is created (with the agent keyword or the tilde operator) is called the agent creation. The feature to which the agent points is the agent callee and the place (or places) where the agent is called is denoted agent call.
class TERMINOLOGY feature f1 local p: PROCEDURE [ANY, TUPLE] do p := agent target -- agent creation end f2 (p: PROCEDURE [ANY, TUPLE]) do p.call ([]) -- agent call end target -- callee do end end
Wrapper generation
Frozen code
Lets look first at frozen code. Class C is used throughout the following examples.
class C feature f (p1, p2: INTEGER; p3: STRING): STRING do ... end end
For everly agent creation a c-function is generated. This wrapper function does the following:
- Reorder the closed and open arguments.
- Calculate the proper agent callee based on the dynamic type of the target.
- Call the agent callee
For the agent creation:
agent c.f (?, 1, ?)
the following wrapper function is generated:
EIF_REFERENCE _fAaatpmf_2_4 (EIF_REFERENCE (*f_ptr)(EIF_REFERENCE, EIF_INTEGER_32, EIF_INTEGER_32, EIF_REFERENCE), EIF_TYPED_ELEMENT* closed, EIF_TYPED_ELEMENT* open) { return (FUNCTION_CAST(EIF_REFERENCE, (EIF_REFERENCE, EIF_INTEGER_32, EIF_INTEGER_32, EIF_REFERENCE)) RTVF(350, 30, "f", closed [1].element.rarg))( closed [1].element.rarg, open [1].element.i32arg, closed [2].element.i32arg, open [2].element.rarg); }
And for this agent creation:
agent {C}.f (1, ?, "hello")
The wrapper function looks like:
EIF_REFERENCE _fAaatpmf_1_3 (EIF_REFERENCE (*f_ptr)(EIF_REFERENCE, EIF_INTEGER_32, EIF_INTEGER_32, EIF_REFERENCE), EIF_TYPED_ELEMENT* closed, EIF_TYPED_ELEMENT* open) { return (FUNCTION_CAST(EIF_REFERENCE, (EIF_REFERENCE, EIF_INTEGER_32, EIF_INTEGER_32, EIF_REFERENCE)) RTVF(350, 30, "f", open [1].element.rarg))( open [1].element.rarg, closed [1].element.i32arg, open [2].element.i32arg, closed [2].element.rarg); }
Finalized code
In finalized code things are only slightly different.
Whenever an agent is created with a closed target, the actual agent callee is calculated at agent creation time.
- Two wrappers are generated:
- one which expects the closed arguments as a tuple (encapsulated). The only difference to the frozen wrapper is how the agent callee is calculated.
- and one that expects them as separate parameters.