1.6 KiB
1.6 KiB
astequal
Package astequal provides AST (deep) equallity check operations.
Installation:
go get github.com/go-toolsmith/astequal
Example
package main
import (
"fmt"
"go/ast"
"go/parser"
"go/token"
"log"
"reflect"
"github.com/go-toolsmith/astequal"
)
func main() {
const code = `
package foo
func main() {
x := []int{1, 2, 3}
x := []int{1, 2, 3}
}`
fset := token.NewFileSet()
pkg, err := parser.ParseFile(fset, "string", code, 0)
if err != nil {
log.Fatalf("parse error: %+v", err)
}
fn := pkg.Decls[0].(*ast.FuncDecl)
x := fn.Body.List[0]
y := fn.Body.List[1]
// Reflect DeepEqual will fail due to different Pos values.
// astequal only checks whether two nodes describe AST.
fmt.Println(reflect.DeepEqual(x, y)) // => false
fmt.Println(astequal.Node(x, y)) // => true
fmt.Println(astequal.Stmt(x, y)) // => true
}
Performance
astequal outperforms reflection-based comparison by a big margin:
BenchmarkEqualExpr/astequal.Expr-8 5000000 298 ns/op 0 B/op 0 allocs/op
BenchmarkEqualExpr/astequal.Node-8 3000000 409 ns/op 0 B/op 0 allocs/op
BenchmarkEqualExpr/reflect.DeepEqual-8 50000 38898 ns/op 10185 B/op 156 allocs/op