spf13--cobra/zsh_completions.go
Haim Ashkenazi 7e2436b79d First try at better zsh completions:
A very basic POC. Need to refactor to generate completion
structure before passing to the template to avoid repeated
computations.

What works:
  * Real zsh completion (not built on bash)
  * Basic flags (with long flag and optional shorthand)
  * Basic filename completion indication (not with file extensions though)

What's missing:
  * File extensions to filename completions
  * Positional args
  * Do we require handling only short flags?
2019-06-07 10:09:50 -04:00

147 lines
3.5 KiB
Go

package cobra
import (
"fmt"
"io"
"os"
"strings"
"text/template"
"github.com/spf13/pflag"
)
var (
funcMap = template.FuncMap{
"constructPath": constructPath,
"subCmdList": subCmdList,
"extractFlags": extractFlags,
"simpleFlag": simpleFlag,
}
zshCompletionText = `
{{/* for pflag.Flag (specifically annotations) */}}
{{define "flagAnnotations" -}}
{{with index .Annotations "cobra_annotation_bash_completion_filename_extensions"}}:filename:_files{{end}}
{{- end}}
{{/* for pflag.Flag with short and long options */}}
{{define "complexFlag" -}}
"(-{{.Shorthand}} --{{.Name}})"{-{{.Shorthand}},--{{.Name}}}"[{{.Usage}}]{{template "flagAnnotations" .}}"
{{- end}}
{{/* for pflag.Flag with either short or long options */}}
{{define "simpleFlag" -}}
"{{with .Name}}--{{.}}{{else}}-{{.Shorthand}}{{end}}[{{.Usage}}]{{template "flagAnnotations" .}}"
{{- end}}
{{/* should accept Command (that contains subcommands) as parameter */}}
{{define "argumentsC" -}}
function {{constructPath .}} {
local line
_arguments -C \
{{range extractFlags . -}}
{{" "}}{{if simpleFlag .}}{{template "simpleFlag" .}}{{else}}{{template "complexFlag" .}}{{end}} \
{{end}} "1: :({{subCmdList .}})" \
"*::arg:->args"
case $line[1] in {{- range .Commands}}
{{.Use}})
{{constructPath .}}
;;
{{end}} esac
}
{{range .Commands}}
{{template "selectCmdTemplate" .}}
{{- end}}
{{- end}}
{{/* should accept Command without subcommands as parameter */}}
{{define "arguments" -}}
function {{constructPath .}} {
{{with extractFlags . -}}
{{ " _arguments" -}}
{{range .}} \
{{if simpleFlag .}}{{template "simpleFlag" .}}{{else}}{{template "complexFlag" .}}{{end -}}
{{end}}
{{end -}}
}
{{- end}}
{{define "selectCmdTemplate" -}}
{{if .Commands}}{{template "argumentsC" .}}{{else}}{{template "arguments" .}}{{end}}
{{- end}}
{{define "Main" -}}
#compdef _{{.Use}} {{.Use}}
{{template "selectCmdTemplate" .}}
{{end}}
`
)
// GenZshCompletionFile generates zsh completion file.
func (c *Command) GenZshCompletionFile(filename string) error {
outFile, err := os.Create(filename)
if err != nil {
return err
}
defer outFile.Close()
return c.GenZshCompletion(outFile)
}
// GenZshCompletion generates a zsh completion file and writes to the passed writer.
func (c *Command) GenZshCompletion(w io.Writer) error {
tmpl, err := template.New("Main").Funcs(funcMap).Parse(zshCompletionText)
if err != nil {
return fmt.Errorf("error creating zsh completion template: %v", err)
}
return tmpl.Execute(w, c)
}
func constructPath(c *Command) string {
var path []string
tmpCmd := c
path = append(path, tmpCmd.Use)
for {
if !tmpCmd.HasParent() {
break
}
tmpCmd = tmpCmd.Parent()
path = append(path, tmpCmd.Use)
}
// reverse path
for left, right := 0, len(path)-1; left < right; left, right = left+1, right-1 {
path[left], path[right] = path[right], path[left]
}
return "_" + strings.Join(path, "_")
}
// subCmdList returns a space separated list of subcommands names
func subCmdList(c *Command) string {
var subCmds []string
for _, cmd := range c.Commands() {
subCmds = append(subCmds, cmd.Use)
}
return strings.Join(subCmds, " ")
}
func extractFlags(c *Command) []*pflag.Flag {
var flags []*pflag.Flag
c.LocalFlags().VisitAll(func(f *pflag.Flag) {
flags = append(flags, f)
})
c.InheritedFlags().VisitAll(func(f *pflag.Flag) {
flags = append(flags, f)
})
return flags
}
func simpleFlag(p *pflag.Flag) bool {
return p.Name == "" || p.Shorthand == ""
}