gistfile1.txt

now, let's convert digraph with `usage`

with the following usage,

var digraphHelp = usage.Text{
	Pages: []usage.Page{{Content: []byte(`
Directed graph.

Usage:
  digraph nodes
  digraph transpose
  digraph somepath <from> <to>
  digraph -h,-help
  digraph -version

Options:
  -h,-help    Show this screen.
  -version     Show version.
`)}},
	Map: map[string]string{},
}

getting error,

digraph: no field found for "digraph"

bit confusing. what is a field? why is it not found?

---------------------------

fixed by adding,

	Map: map[string]string{
		"nodes":     "entity",
		"transpose": "entity",
		"somepath":  "entity",
	},
  
ok, so you can provide a pre-struct mapping with this map. i get it now!

---------------------------

honestly, pretty quick to get started. this is really neat!

---------------------------

got -h | --h | -help | --help working with:

var digraphHelp = usage.Text{
	Pages: []usage.Page{{Content: []byte(`
Directed graph.

Usage:
  digraph nodes
  digraph transpose
  digraph somepath <from> <to>
  digraph -h,-help
  digraph -v,-version

Options:
  -h,-help       Show this screen.
  -v,-version    Show version.
`)}},
	Map: map[string]string{
		"nodes":     "entity",
		"transpose": "entity",
		"somepath":  "entity",
	},
}

pretty slick how -foo and --foo are equally valid, without having to specify all of them

---------------------------

when I try to -version, i get:

digraph: flag v present but not allowed

that's odd:

1. it's set up the exact same as -help wut?
2. why is it saying "flag v present" when it's actually flag -version

(-v gives us the same issue)

---------------------------

sidenote: not sure if there's a better way to print usage than,

	if opts.Help {
		fmt.Println(string(digraphHelp.Pages[0].Content))
		return nil
	}
  
feels a bit janky. i reached for something like usage.Usage(digraphHelp), but it doesn't exist AFAICT

also, when would you have multiple pages? probably will find the answer out as i go further down the rabbit hole

---------------------------

sidenote: looking at naval_fate, why are we defining -v and -h in both Usage and Options? is that required? bit confusing

---------------------------

having a hard time figuring out this "flag v present but not allowed" error :/

seems like everything is in order. wish the error would tell me more

---------------------------

ah, this appears to be a bug with usage.peg. when i remove the -h,-help, my issue disappears and -v starts working

---------------------------

ah, there are more issues. for example:

$ go build . && cat input.txt | ./digraph -help nodes
digraph: flag h present but not allowed

$ go build . && cat input.txt | ./digraph nodes -help
digraph: flag h present but not allowed

---------------------------

this should probably be an error, but is not:

$ go build . && cat input.txt | ./digraph nodes somepath
bar
foo
gaz

---------------------------

similarly, should be an error but is not:

$ go build . && cat input.txt | ./digraph nodes nodes
bar
foo
gaz

---------------------------

this "command not found" message is broken:

$ go build . && cat input.txt | ./digraph foo
digraph: no such command ""

here, it's entering my default case of opts.Entity, since opts.Entity is being set to empty string. probably instead
of empty string for opts.Entity, `usage.Process` should have thrown an error that the input doesn't match `digraphUsage`

similarly, when I pass no args (`./digraph`), it again just sets opts.Entity to empty string and continues, when it
should throw a usage error

---------------------------

subcommands and flags for subcommands are really easy, and intuitive. the following "just works":

var digraphHelp = usage.Text{
	Pages: []usage.Page{{Content: []byte(`
Directed graph.

Usage:
  digraph nodes
  digraph transpose
  digraph somepath <from> <to>
  digraph newcmd foo [-gaz]
  digraph newcmd bar [-gaz]
  digraph -h,-help
  digraph -v,-version

Options:
  -h,-help       Show this screen.
  -v,-version    Show version.
  -gaz           Does... nothing, really.
`)}},
	Map: map[string]string{
		"nodes":     "entity",
		"transpose": "entity",
		"somepath":  "entity",
		"newcmd":    "entity",
		"foo":       "newcmdaction",
		"bar":       "newcmdaction",
	},
}

that's very neat!

i imagine with pages it'll be quite easy to implement `help subcmd`