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help : HelpError holds cmd.Subcommand and summary : NewHelpError constructor

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This commit is contained in:
bth 2026-01-29 11:09:55 -08:00
commit 8fe659a171
9 changed files with 51 additions and 36 deletions
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3
cat/cat.go
View file

@ -83,7 +83,8 @@ func cat(files []string, opts options) (string, error) {
func Cat(args []string) {
opts := initOpts()
if err := flags.ParseArgs(CMD, SUMMARY, args, &opts); err != nil {
help := flags.NewHelpError(CMD, SUMMARY)
if err := flags.ParseArgs(help, args, &opts); err != nil {
var herr flags.HelpError
if errors.As(err, &herr) {
fmt.Println(herr)

17
flags/flags.go
View file

@ -4,8 +4,6 @@ import (
"log"
"reflect"
"strings"
"github.com/brtholomy/um/go/cmd"
)
const INTERNAL_ERR_PREFIX = "um internal err: ParseArgs"
@ -155,7 +153,10 @@ func expandOpts(opts any) []Flag {
}
// internal for type safety testing
func parseArgsInternal(sub cmd.Subcommand, summary string, args []string, opts any, flags []Flag) error {
//
// NOTE: we aren't currently returning any other kind of error, so keeping HelpError as error type
// may be unnecessary, although it allows another err eventually.
func parseArgsInternal(help HelpError, args []string, opts any, flags []Flag) error {
argloop:
for i := 0; i < len(args); i++ {
arg := args[i]
@ -164,10 +165,10 @@ argloop:
if f.IsHelp() {
// so Help.Val is true to avoid confusion:
f.Set(arg)
return Help(sub, summary, opts)
return help.Help(opts)
}
if !f.Valid(args, i) {
return HelpMissingAssignment(sub, arg)
return help.HelpMissingAssignment(arg)
}
i = f.MaybeIncrement(i)
f.Set(args[i])
@ -175,13 +176,13 @@ argloop:
}
}
// NOTE: if we didn't skip ahead, arg didn't match:
return HelpInvalidArg(sub, arg)
return help.HelpInvalidArg(arg)
}
return nil
}
// assign values of args to opts struct using Flag interface methods
func ParseArgs(sub cmd.Subcommand, summary string, args []string, opts any) error {
func ParseArgs(help HelpError, args []string, opts any) error {
flags := expandOpts(opts)
return parseArgsInternal(sub, summary, args, opts, flags)
return parseArgsInternal(help, args, opts, flags)
}

10
flags/flags_test.go
View file

@ -11,6 +11,8 @@ const (
SUMMARY = "SUMMARY"
)
var helpErr = NewHelpError(CMD, SUMMARY)
type options struct {
Descriptor Arg
Tags Arg
@ -38,7 +40,7 @@ func TestParseArgsInternal(t *testing.T) {
&Bool{"--help", "-h", false, "show help"},
}
args := []string{"--source", "foo"}
parseArgsInternal(CMD, SUMMARY, args, initOpts(), flags)
parseArgsInternal(helpErr, args, initOpts(), flags)
assert.False(t, flags[0].IsSet())
assert.False(t, flags[0].IsHelp())
assert.True(t, flags[2].IsSet())
@ -49,7 +51,7 @@ func TestParseArgsInternal(t *testing.T) {
func TestParseArgsHelp(t *testing.T) {
args := []string{"--help"}
opts := initOpts()
err := ParseArgs(CMD, SUMMARY, args, &opts)
err := ParseArgs(helpErr, args, &opts)
assert.ErrorContains(t, err, "um TEST [descriptor] [tags] [--source] [--write]\n\nSUMMARY")
// we set the Val true although we don't expect to use it:
assert.True(t, opts.Help.Val)
@ -58,7 +60,7 @@ func TestParseArgsHelp(t *testing.T) {
func TestParseArgsString(t *testing.T) {
args := []string{"--source", "foo"}
opts := initOpts()
err := ParseArgs(CMD, SUMMARY, args, &opts)
err := ParseArgs(helpErr, args, &opts)
assert.NoError(t, err)
assert.Equal(t, opts.Source.Val, "foo")
}
@ -82,7 +84,7 @@ func TestParseArgs(t *testing.T) {
for _, tc := range cases {
t.Run(tc.name, func(t *testing.T) {
err := ParseArgs(CMD, SUMMARY, tc.args, &opts)
err := ParseArgs(helpErr, tc.args, &opts)
assert.NoError(t, err)
if tc.boolVal != nil {
assert.True(t, *tc.boolVal)

40
flags/help.go
View file

@ -11,6 +11,8 @@ import (
)
type HelpError struct {
sub cmd.Subcommand
summary string
message string
}
@ -18,27 +20,30 @@ func (h HelpError) Error() string {
return h.message
}
func HelpRequired(sub cmd.Subcommand, long string) error {
return HelpError{
fmt.Sprintf("um %s: %s is required", sub, long),
}
// TODO: is this odd? Constructing an error at the callsite and passing it down and back up?
// but how else should I fill out its fields to be reused later?
func NewHelpError(sub cmd.Subcommand, summary string) HelpError {
return HelpError{sub, summary, ""}
}
func HelpInvalidArg(sub cmd.Subcommand, arg string) error {
return HelpError{
fmt.Sprintf("um %s: invalid argument: %s", sub, arg),
}
func (h HelpError) HelpRequired(long string) error {
h.message = fmt.Sprintf("um %s: %s is required", h.sub, long)
return h
}
func HelpMissingAssignment(sub cmd.Subcommand, arg string) error {
return HelpError{
fmt.Sprintf("um %s: %s needs a value assignment", sub, arg),
}
func (h HelpError) HelpInvalidArg(arg string) error {
h.message = fmt.Sprintf("um %s: invalid argument: %s", h.sub, arg)
return h
}
// print out help string by reflecting over fields of provided opts struct
// and os.Exit(0)
func Help(sub cmd.Subcommand, summary string, opts any) error {
func (h HelpError) HelpMissingAssignment(arg string) error {
h.message = fmt.Sprintf("um %s: %s needs a value assignment", h.sub, arg)
return h
}
// assemble --help string by reflecting over fields of provided opts struct
func (h HelpError) Help(opts any) error {
v := reflect.ValueOf(opts)
if v.Kind() == reflect.Ptr {
v = v.Elem()
@ -68,9 +73,10 @@ func Help(sub cmd.Subcommand, summary string, opts any) error {
)
}
}
if _, err := buf.WriteString(fmt.Sprintf("um %s%s\n\n%s\n\n", sub, positional, summary)); err != nil {
if _, err := buf.WriteString(fmt.Sprintf("um %s%s\n\n%s\n\n", h.sub, positional, h.summary)); err != nil {
return err
}
w.Flush()
return HelpError{buf.String()}
h.message = buf.String()
return h
}

3
last/last.go
View file

@ -46,7 +46,8 @@ func GlobLast(glob string) (string, error) {
func Last(args []string) {
opts := initOpts()
if err := flags.ParseArgs(CMD, SUMMARY, args, &opts); err != nil {
help := flags.NewHelpError(CMD, SUMMARY)
if err := flags.ParseArgs(help, args, &opts); err != nil {
var herr flags.HelpError
if errors.As(err, &herr) {
fmt.Println(herr)

3
mv/mv.go
View file

@ -90,7 +90,8 @@ func mv(opts options) error {
func Mv(args []string) {
opts := initOpts()
if err := flags.ParseArgs(CMD, SUMMARY, args, &opts); err != nil {
help := flags.NewHelpError(CMD, SUMMARY)
if err := flags.ParseArgs(help, args, &opts); err != nil {
var herr flags.HelpError
if errors.As(err, &herr) {
fmt.Println(herr)

3
next/next.go
View file

@ -100,7 +100,8 @@ func emacsNext(f string, tags string) error {
func Next(args []string) {
opts := initOpts()
if err := flags.ParseArgs(CMD, SUMMARY, args, &opts); err != nil {
help := flags.NewHelpError(CMD, SUMMARY)
if err := flags.ParseArgs(help, args, &opts); err != nil {
var herr flags.HelpError
if errors.As(err, &herr) {
fmt.Println(herr)

5
sort/sort.go
View file

@ -70,7 +70,8 @@ func write(file string, content string) {
func Sort(args []string) {
opts := initOpts()
if err := flags.ParseArgs(CMD, SUMMARY, args, &opts); err != nil {
help := flags.NewHelpError(CMD, SUMMARY)
if err := flags.ParseArgs(help, args, &opts); err != nil {
var herr flags.HelpError
if errors.As(err, &herr) {
fmt.Println(herr)
@ -80,7 +81,7 @@ func Sort(args []string) {
}
// BORK: by hand for now:
if !opts.Key.IsSet() {
fmt.Println(flags.HelpRequired(CMD, opts.Key.Long))
fmt.Println(help.HelpRequired(opts.Key.Long))
return
}

3
tag/tag.go
View file

@ -36,7 +36,8 @@ func initOpts() options {
func Tag(args []string) {
opts := initOpts()
if err := flags.ParseArgs(CMD, SUMMARY, args, &opts); err != nil {
help := flags.NewHelpError(CMD, SUMMARY)
if err := flags.ParseArgs(help, args, &opts); err != nil {
var herr flags.HelpError
if errors.As(err, &herr) {
fmt.Println(herr)