feat: void return gadgets, multiple circuits export and Vector op…

…timisation (#38)

* Added check in CallGadget

* Added support for gadgets with no return types

* Fixed const type coercion

* Added support for extraction of multiple gadgets

* Added support of Compiler interface

* Improved gadget naming

* Fixes to nested array of int in gadgets

* Added uninitialised structs

* Fixed sanitizeVars to support all flavours of ints

* Added extraction of multiple circuits

* Added vector optimisation

* Added vector optimisation in gadget return

* Added size check in isVectorComplete

* Added support for array of ints as parameters

* Fixed debug

* Fixed use of append

* Improved gotest

* Fixed gate vector optimisation

* Fixed clone gadget function

* Added 2dim slices optimisation

* Added tests

* Added support of n-dim slices optimisation

* Added support for multiple gadget return types

* Fix replaceArg

* Fixed nested slices

* Moved public mathods to interface.go

* Tests moved to test folder

* Moving generic functions to file misc.go

* Added comments and refactoring

* Added comments and error handling

* Gofmt

README.md

@@ -40,15 +40,15 @@ func (circuit *MyCircuit) AbsDefine(api abstractor.API) error {
     return nil
 }
 
-func (circuit *MyCircuit) Define(api frontend.API) error {
-    return abstractor.Concretize(api, circuit)
+func (circuit MyCircuit) Define(api frontend.API) error {
+    return abstractor.Concretize(api, &circuit)
 }
 ```
 
 Once you export this to Lean, you get a definition as follows:
 
 ```lean
-namespace DummyCircuit
+namespace MyCircuit
 
 def Order : ℕ := 0x30644e72e131a029b85045b68181585d2833e84879b9709143e1f593f0000001
 variable [Fact (Nat.Prime Order)]
@@ -59,7 +59,7 @@ def circuit (In_1: F) (In_2: F) (Out: F): Prop :=
     Gates.eq gate_0 Out ∧
     True
 
-end DummyCircuit
+end MyCircuit
 ```
 
 Further examples of this process with various levels of complexity can be seen

abstractor/abstractor.go

@@ -3,19 +3,19 @@ package abstractor
 import "github.com/consensys/gnark/frontend"
 
 type Gadget interface {
-	Call(gadget GadgetDefinition) []frontend.Variable
+	Call(gadget GadgetDefinition) interface{}
 }
 
 type GadgetDefinition interface {
-	DefineGadget(api API) []frontend.Variable
+	DefineGadget(api API) interface{}
 }
 
 type API interface {
 	frontend.API
 	DefineGadget(gadget GadgetDefinition) Gadget
 
 	frontend.API
-	Call(gadget GadgetDefinition) []frontend.Variable
+	Call(gadget GadgetDefinition) interface{}
 }
 
 type Circuit interface {
@@ -27,6 +27,13 @@ func Concretize(api frontend.API, circuit Circuit) error {
 	return circuit.AbsDefine(&Concretizer{api})
 }
 
-func CallGadget(api frontend.API, circuit GadgetDefinition) []frontend.Variable {
+func CallGadget(api frontend.API, circuit GadgetDefinition) interface{} {
+	_, ok := api.(API)
+	if ok {
+		// The consequence of calling CallGadget with abstractor.API is that
+		// the circuit is extracted as a single function instead of
+		// splitting in sub-circuits
+		panic("abstractor.CallGadget can't be called with abstractor.API")
+	}
 	return circuit.DefineGadget(&Concretizer{api})
 }

abstractor/concretizer.go

@@ -10,7 +10,7 @@ type ConcreteGadget struct {
 	api API
 }
 
-func (g *ConcreteGadget) Call(gadget GadgetDefinition) []frontend.Variable {
+func (g *ConcreteGadget) Call(gadget GadgetDefinition) interface{} {
 	return gadget.DefineGadget(g.api)
 }
 
@@ -122,7 +122,7 @@ func (c *Concretizer) DefineGadget(gadget GadgetDefinition) Gadget {
 	return &ConcreteGadget{c}
 }
 
-func (c *Concretizer) Call(gadget GadgetDefinition) []frontend.Variable {
+func (c *Concretizer) Call(gadget GadgetDefinition) interface{} {
 	return c.DefineGadget(gadget).Call(gadget)
 }