mirror of
https://github.com/rwxrob/bonzai
synced 2024-11-14 18:12:59 +00:00
53 lines
1.5 KiB
Go
53 lines
1.5 KiB
Go
package Z
|
|
|
|
import (
|
|
"fmt"
|
|
"strings"
|
|
|
|
"github.com/rwxrob/fn/filt"
|
|
)
|
|
|
|
// UsageGroup uses Bonzai usage notation, a basic form of regular
|
|
// expressions, to describe the arguments allowed where each argument is
|
|
// a literal string (avoid spaces). The arguments are joined with bars
|
|
// (|) and wrapped with parentheses producing a regex group. The min
|
|
// and max are then applied by adding the following regex decorations
|
|
// after the final parenthesis:
|
|
//
|
|
// - min=1 max=1 (exactly one)
|
|
// ? - min=0 max=0 (none or many)
|
|
// + - min=1 max=0 (one or more)
|
|
// {min,} - min>0 max=0 (min, no max)
|
|
// {min,max} - min>0 max>0 (min and max)
|
|
// {,max} - min=0 max>0 (max, no min)
|
|
//
|
|
// An empty args slice returns an empty string. If only one arg, then
|
|
// that arg is simply returned and min and max are ignored. Arguments
|
|
// that are empty strings are ignored. No transformation is done to the
|
|
// string itself (such as removing white space).
|
|
func UsageGroup(args []string, min, max int) string {
|
|
args = filt.NotEmpty(args)
|
|
switch len(args) {
|
|
case 0:
|
|
return ""
|
|
case 1:
|
|
return args[0]
|
|
default:
|
|
var dec string
|
|
switch {
|
|
case min == 1 && max == 1:
|
|
case min == 0 && max == 0:
|
|
dec = "?"
|
|
case min == 1 && max == 0:
|
|
dec = "+"
|
|
case min > 1 && max == 0:
|
|
dec = fmt.Sprintf("{%v,}", min)
|
|
case min > 0 && max > 0:
|
|
dec = fmt.Sprintf("{%v,%v}", min, max)
|
|
case min == 0 && max > 1:
|
|
dec = fmt.Sprintf("{,%v}", max)
|
|
}
|
|
return "(" + strings.Join(args, "|") + ")" + dec
|
|
}
|
|
}
|