mirror of
https://github.com/diamondburned/arikawa.git
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269 lines
5.7 KiB
Go
269 lines
5.7 KiB
Go
package bot
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import (
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"errors"
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"reflect"
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"strconv"
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"strings"
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)
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type argumentValueFn func(string) (reflect.Value, error)
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// Parser implements a Parse(string) method for data structures that can be
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// used as arguments.
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type Parser interface {
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Parse(string) error
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}
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// Usager is used in place of the automatically parsed struct name for Parser
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// and other interfaces.
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type Usager interface {
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Usage() string
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}
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// ManualParser has a ParseContent(string) method. If the library sees
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// this for an argument, it will send all of the arguments into the method. If
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// used, this should be the only argument followed after the Message Create
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// event. Any more and the router will ignore.
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type ManualParser interface {
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// $0 will have its prefix trimmed.
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ParseContent([]string) error
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}
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// ArgumentParts implements ManualParser, in case you want to parse arguments
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// manually. It borrows the library's argument parser.
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type ArgumentParts []string
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var _ ManualParser = (*ArgumentParts)(nil)
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// ParseContent implements ManualParser.
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func (r *ArgumentParts) ParseContent(args []string) error {
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*r = args
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return nil
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}
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func (r ArgumentParts) Arg(n int) string {
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if n < 0 || n >= len(r) {
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return ""
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}
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return r[n]
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}
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func (r ArgumentParts) After(n int) string {
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if n < 0 || n > len(r) {
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return ""
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}
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return strings.Join(r[n:], " ")
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}
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func (r ArgumentParts) String() string {
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return strings.Join(r, " ")
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}
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func (r ArgumentParts) Length() int {
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return len(r)
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}
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// Usage implements Usager.
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func (r ArgumentParts) Usage() string {
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return "strings"
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}
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// CustomParser has a CustomParse method, which would be passed in the full
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// message content with the prefix, command, subcommand and space trimmed. This
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// is used for commands that require more advanced parsing than the default
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// parser.
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type CustomParser interface {
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CustomParse(arguments string) error
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}
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// RawArguments implements the CustomParser interface, which sets all the
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// arguments into it as raw as it could.
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type RawArguments string
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var _ CustomParser = (*RawArguments)(nil)
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func (a *RawArguments) CustomParse(arguments string) error {
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*a = RawArguments(arguments)
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return nil
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}
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// Argument is each argument in a method.
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type Argument struct {
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String string
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// Rule: pointer for structs, direct for primitives
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rtype reflect.Type
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// indicates if the type is referenced, meaning it's a pointer but not the
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// original call.
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pointer bool
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// if nil, then manual
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fn argumentValueFn
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manual func(ManualParser, []string) error
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custom func(CustomParser, string) error
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}
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func (a *Argument) Type() reflect.Type {
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return a.rtype
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}
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var ShellwordsEscaper = strings.NewReplacer(
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"\\", "\\\\",
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)
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// nilV, only used to return an error
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var nilV = reflect.Value{}
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func newArgument(t reflect.Type, variadic bool) (*Argument, error) {
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// Allow array types if variadic is true.
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if variadic && t.Kind() == reflect.Slice {
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t = t.Elem()
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}
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var typeI = t
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var ptr = false
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if t.Kind() != reflect.Ptr {
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typeI = reflect.PtrTo(t)
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ptr = true
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}
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// This shouldn't be variadic.
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if !variadic && typeI.Implements(typeICusP) {
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if t.Kind() == reflect.Ptr {
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t = t.Elem()
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}
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return &Argument{
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String: fromUsager(t),
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rtype: t,
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pointer: ptr,
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custom: CustomParser.CustomParse,
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}, nil
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}
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// This shouldn't be variadic either.
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if !variadic && typeI.Implements(typeIManP) {
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if t.Kind() == reflect.Ptr {
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t = t.Elem()
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}
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return &Argument{
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String: fromUsager(t),
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rtype: t,
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pointer: ptr,
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manual: ManualParser.ParseContent,
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}, nil
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}
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if typeI.Implements(typeIParser) {
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mt, ok := typeI.MethodByName("Parse")
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if !ok {
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panic("BUG: type IParser does not implement Parse")
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}
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avfn := func(input string) (reflect.Value, error) {
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v := reflect.New(typeI.Elem())
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ret := mt.Func.Call([]reflect.Value{
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v, reflect.ValueOf(input),
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})
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_, err := errorReturns(ret)
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if err != nil {
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return nilV, err
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}
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if ptr {
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v = v.Elem()
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}
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return v, nil
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}
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return &Argument{
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String: fromUsager(typeI),
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rtype: typeI,
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pointer: ptr,
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fn: avfn,
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}, nil
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}
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var fn argumentValueFn
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switch t.Kind() {
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case reflect.String:
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fn = func(s string) (reflect.Value, error) {
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return reflect.ValueOf(s), nil
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}
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case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
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fn = func(s string) (reflect.Value, error) {
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i, err := strconv.ParseInt(s, 10, 64)
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return quickRet(i, err, t)
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}
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case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
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fn = func(s string) (reflect.Value, error) {
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u, err := strconv.ParseUint(s, 10, 64)
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return quickRet(u, err, t)
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}
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case reflect.Float32, reflect.Float64:
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fn = func(s string) (reflect.Value, error) {
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f, err := strconv.ParseFloat(s, 64)
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return quickRet(f, err, t)
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}
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case reflect.Bool:
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fn = func(s string) (reflect.Value, error) {
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switch s {
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case "True", "TRUE", "true", "T", "t", "yes", "y", "Y", "1":
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return reflect.ValueOf(true), nil
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case "False", "FALSE", "false", "F", "f", "no", "n", "N", "0":
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return reflect.ValueOf(false), nil
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default:
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return nilV, errors.New("invalid bool [true|false]")
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}
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}
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}
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if fn == nil {
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return nil, errors.New("invalid type: " + t.String())
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}
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return &Argument{
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String: fromUsager(t),
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rtype: t,
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fn: fn,
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}, nil
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}
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func quickRet(v interface{}, err error, t reflect.Type) (reflect.Value, error) {
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if err != nil {
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return nilV, err
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}
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rv := reflect.ValueOf(v)
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if t == nil {
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return rv, nil
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}
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return rv.Convert(t), nil
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}
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func fromUsager(typeI reflect.Type) string {
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if typeI.Implements(typeIUsager) {
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mt, _ := typeI.MethodByName("Usage")
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vs := mt.Func.Call([]reflect.Value{reflect.New(typeI).Elem()})
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return vs[0].String()
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}
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s := strings.Split(typeI.String(), ".")
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return s[len(s)-1]
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}
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