Go Contract Extraction

Overview

The Go extractor scans a package directory for .go files (excluding _test.go) and uses tree-sitter-go to parse them. It identifies structs, interfaces, functions, and methods, extracting only exported symbols.

API

from goga.contract.golang import golang_contract

contracts = golang_contract("path/to/package")
# Returns list[EntityContract | RoutineContract]

golang_contract accepts a path to a Go package directory. Returns an empty list if no .go files are found.

What Gets Extracted

Source Construct	Contract Type	Notes
type X struct {}	EntityContract	Exported struct fields become properties
type X interface {}	EntityContract	Interface methods are collected
func X()	RoutineContract	Exported top-level functions
func (r *X) M()	MethodContract	Methods attached to their receiver struct

Visibility Rules

• Only exported (uppercase) names are included
• Unexported struct fields are excluded
• Unexported methods are excluded
• Methods are attached to struct entities only (not interfaces)
• _test.go files are skipped

Key Node Types

The parser walks these tree-sitter node types:

• type_declaration -- struct and interface declarations
• function_declaration -- top-level function declarations
• method_declaration -- method declarations with receivers
• interface_type -- interface method sets
• struct_type -- struct field lists

Example

Given a Go package with two files:

// model.go
package cell

type Server struct {
    Name string
    Port int
}

// methods.go
package cell

func (s *Server) Start() error { return nil }
func (s *Server) Stop()        {}
func Hello(name string) string  { return "Hello " + name }

The extracted contracts are:

Name	Type	Signature
Server	EntityContract	()
Hello	RoutineContract	(name: string) -> string

Server has two properties (Name: string, Port: int) and two methods (Start() -> error, Stop()).