diff --git a/usage.go b/usage.go index 9404015..2c38fe7 100644 --- a/usage.go +++ b/usage.go @@ -68,11 +68,24 @@ func (p *Parser) WriteHelp(w io.Writer) { p.WriteUsage(w) + // the width of the left column + const colWidth = 25 + // write the list of positionals if len(positionals) > 0 { fmt.Fprint(w, "\npositional arguments:\n") for _, spec := range positionals { - fmt.Fprintf(w, " %s\n", spec.long) + left := " " + spec.long + fmt.Fprint(w, left) + if spec.help != "" { + if len(left)+2 < colWidth { + fmt.Fprint(w, strings.Repeat(" ", colWidth-len(left))) + } else { + fmt.Fprint(w, "\n"+strings.Repeat(" ", colWidth)) + } + fmt.Fprint(w, spec.help) + } + fmt.Fprint(w, "\n") } } diff --git a/usage_test.go b/usage_test.go index 5a9199c..4a56e6e 100644 --- a/usage_test.go +++ b/usage_test.go @@ -16,7 +16,7 @@ func TestWriteUsage(t *testing.T) { positional arguments: input - output + output positional output options: --verbose, -v verbosity level @@ -27,7 +27,7 @@ options: ` var args struct { Input string `arg:"positional"` - Output []string `arg:"positional"` + Output []string `arg:"positional,help:positional output"` Verbose bool `arg:"-v,help:verbosity level"` Dataset string `arg:"help:dataset to use"` Optimize int `arg:"-O,help:optimization level"` @@ -45,3 +45,26 @@ options: p.WriteHelp(&help) assert.Equal(t, expectedHelp, help.String()) } + +func TestUsageLongPositionalWithHelp(t *testing.T) { + expectedHelp := `usage: example VERYLONGPOSITIONALWITHHELP + +positional arguments: + verylongpositionalwithhelp + this positional argument is very long + +options: + --help, -h display this help and exit +` + var args struct { + VeryLongPositionalWithHelp string `arg:"positional,help:this positional argument is very long"` + } + + p, err := NewParser(&args) + require.NoError(t, err) + + os.Args[0] = "example" + var help bytes.Buffer + p.WriteHelp(&help) + assert.Equal(t, expectedHelp, help.String()) +}