Session Type Provider

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Session Type Providers (STP)

STP is a type provider in F# that generates APIs from protocol specifications.

Consider the following protocol, between a client and a server. The protocol below specifies that a client sends a message tagged as DIV (stands for division operation), containing two payloads. Then the Server replies with a message RES (stands for result) with one integer payload.

Scribble protocol:

DIV(x:int, y:int) from C to S; 
RES(z:int) from S to C; 

F# program

s = STP<"Protocol.scr", C>
let z = Buf<int>()
s.send(S, Div, 4, 2).receive(S, Res, z)

Support for interaction refinements

The tool supports also checks of payload constraints. For example, we can augment the protocol below to specify that the second argument of a divition cannot be zero.

DIV(x:int, y:int) from C to S; @{y!=0}  
RES(z:int) from S to C; 

Then the geenrated code for sending will explicitly contain the specified check.


CC’18: Session type Provider: Compile-time API Generation for Distributed Protocols with Interaction Refinements in F#