forked from elves/elvish
/
raw_options.go
54 lines (45 loc) · 1.31 KB
/
raw_options.go
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package eval
import (
"errors"
"reflect"
"github.com/elves/elvish/parse"
"github.com/elves/elvish/util"
)
type RawOptions map[string]interface{}
// Scan takes a pointer to a struct and scan options into it. A field
// named FieldName corresponds to the option named field-name, unless the field
// has a explicit "name" tag.
func (rawOpts RawOptions) Scan(ptr interface{}) {
ptrValue := reflect.ValueOf(ptr)
if ptrValue.Kind() != reflect.Ptr || ptrValue.Elem().Kind() != reflect.Struct {
throwf("internal bug: need struct ptr to scan options, got %T", ptr)
}
struc := ptrValue.Elem()
// fieldIdxForOpt maps option name to the index of field in struc.
fieldIdxForOpt := make(map[string]int)
for i := 0; i < struc.Type().NumField(); i++ {
// ignore unexported fields
if !struc.Field(i).CanSet() {
continue
}
f := struc.Type().Field(i)
optName := f.Tag.Get("name")
if optName == "" {
optName = util.CamelToDashed(f.Name)
}
fieldIdxForOpt[optName] = i
}
for k, v := range rawOpts {
fieldIdx, ok := fieldIdxForOpt[k]
if !ok {
throwf("unknown option %s", parse.Quote(k))
}
mustScanToGo(v, struc.Field(fieldIdx).Addr().Interface())
}
}
var ErrNoOptAccepted = errors.New("no option accepted")
func TakeNoOpt(opts map[string]interface{}) {
if len(opts) > 0 {
throw(ErrNoOptAccepted)
}
}