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package main
import (
"fmt"
"github.com/hashicorp/go-bexpr"
)
type Example struct {
X int
// Can renamed a field with the struct tag
Y string `bexpr:"y"`
// Fields can use multiple names for accessing
Z bool `bexpr:"Z,z,foo"`
// Tag with "-" to prevent allowing this field from being used
Hidden string `bexpr:"-"`
// Unexported fields are not available for evaluation
unexported string
}
func main() {
value := map[string]Example{
"foo": Example{X: 5, Y: "foo", Z: true, Hidden: "yes", unexported: "no"},
"bar": Example{X: 42, Y: "bar", Z: false, Hidden: "no", unexported: "yes"},
}
expressions := []string{
"foo.X == 5",
"bar.y == bar",
"foo.foo != false",
"foo.z == true",
"foo.Z == true",
// will error in evaluator creation
"bar.Hidden != yes",
// will error in evaluator creation
"foo.unexported == no",
}
for _, expression := range expressions {
eval, err := bexpr.CreateEvaluatorForType(expression, nil, (*map[string]Example)(nil))
if err != nil {
fmt.Printf("Failed to create evaluator for expression %q: %v\n", expression, err)
continue
}
result, err := eval.Evaluate(value)
if err != nil {
fmt.Printf("Failed to run evaluation of expression %q: %v\n", expression, err)
continue
}
fmt.Printf("Result of expression %q evaluation: %t\n", expression, result)
}
}
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