Package builder provides an implementation based on the gnark frontend builder with the following modifications: - LinearExpression has been changed to allow for quadratic terms in the form of Expression.

Package layered defines the structures and functions necessary for creating and manipulating layered circuits within the ExpanderCompilerCollection compiler.

Poseidon hash function, written in the layered circuit.

Compile is similar to gnark's frontend.Compile.

DeserializeInputSolver takes a byte buffer and returns a pointer to an ir.InputSolver which represents a deserialized input solver.

DeserializeLayeredCircuit takes a byte buffer and returns a pointer to a layered.RootCircuit which represents a deserialized layered circuit.

CompileResult represents the result of a compilation process.

API encapsulates the ecgo's frontend.API along with two new APIs added to facilitate direct invocation of ecgo.API within the codebase.