commands: parse arguments with go-opt

Use the argument parsing framework introduced earlier to unify the
parsing of (almost) all command options. Remove custom parsing code and
to avoid extraneous types, add fields with `opt` tags on command structs
that have options and arguments. Commands that take no argument do not
need anything.

Since the command objects now carry data, create a new temporary
instance of them before passing them to opt.ArgsToStruct when executing
a command.

A few of the commands use specific semantics for parsing (:choose), or
are delegating argument parsing to another function (:sort, :search,
:filter). For these commands, simply add a dummy "-" passthrough
argument. Since all commands still have the argument list (after split)
nothing needs to be changed in this area.

There should be no functional change besides the Usage strings and
reported errors which are now generated automatically.

Signed-off-by: Robin Jarry <robin@jarry.cc>
Reviewed-by: Koni Marti <koni.marti@gmail.com>
Tested-by: Moritz Poldrack <moritz@poldrack.dev>
Tested-by: Inwit <inwit@sindominio.net>

1 files changed, 19 insertions, 11 deletions

diff --git a/commands/help.go b/commands/help.go
index 5cc0aacc..b2bcdf7c 100644
--- a/commands/help.go
+++ b/commands/help.go
@@ -1,12 +1,14 @@
 package commands
 
 import (
-	"errors"
+	"fmt"
 
 	"git.sr.ht/~rjarry/aerc/app"
 )
 
-type Help struct{}
+type Help struct {
+	Topic string `opt:"topic" action:"ParseTopic" default:"aerc"`
+}
 
 var pages = []string{
 	"aerc",
@@ -37,15 +39,21 @@ func (Help) Complete(args []string) []string {
 	return CompletionFromList(pages, args)
 }
 
-func (Help) Execute(args []string) error {
-	page := "aerc"
-	if len(args) == 2 && args[1] != "aerc" {
-		page = "aerc-" + args[1]
-	} else if len(args) > 2 {
-		return errors.New("Usage: help [topic]")
+func (h *Help) ParseTopic(arg string) error {
+	for _, page := range pages {
+		if arg == page {
+			if arg != "aerc" {
+				arg = "aerc-" + arg
+			}
+			h.Topic = arg
+			return nil
+		}
 	}
+	return fmt.Errorf("unknown topic %q", arg)
+}
 
-	if page == "aerc-keys" {
+func (h Help) Execute(args []string) error {
+	if h.Topic == "aerc-keys" {
 		app.AddDialog(app.NewDialog(
 			app.NewListBox(
 				"Bindings: Press <Esc> or <Enter> to close. "+
@@ -61,6 +69,6 @@ func (Help) Execute(args []string) error {
 		))
 		return nil
 	}
-
-	return TermCore([]string{"term", "man", page})
+	term := Term{Cmd: []string{"man", h.Topic}}
+	return term.Execute(args)
 }