1 files changed, 94 insertions, 0 deletions
diff --git a/complete.go b/complete.go
new file mode 100644
index 0000000..925c9a2
--- /dev/null
+++ b/complete.go
@@ -0,0 +1,94 @@
+// Package complete provides a tool for bash writing bash completion in go.
+//
+// Writing bash completion scripts is a hard work. This package provides an easy way
+// to create bash completion scripts for any command, and also an easy way to install/uninstall
+// the completion of the command.
+package complete
+
+import (
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/posener/complete/cmd"
+)
+
+const (
+	envComplete = "COMP_LINE"
+	envDebug    = "COMP_DEBUG"
+)
+
+// Complete structs define completion for a command with CLI options
+type Complete struct {
+	Command Command
+	cmd.CLI
+}
+
+// New creates a new complete command.
+// name is the name of command we want to auto complete.
+// IMPORTANT: it must be the same name - if the auto complete
+// completes the 'go' command, name must be equal to "go".
+// command is the struct of the command completion.
+func New(name string, command Command) *Complete {
+	return &Complete{
+		Command: command,
+		CLI:     cmd.CLI{Name: name},
+	}
+}
+
+// Run get a command, get the typed arguments from environment
+// variable, and print out the complete options
+// returns success if the completion ran or if the cli matched
+// any of the given flags, false otherwise
+func (c *Complete) Run() bool {
+	args, ok := getLine()
+	if !ok {
+		// make sure flags parsed,
+		// in case they were not added in the main program
+		return c.CLI.Run()
+	}
+	Log("Completing args: %s", args)
+
+	options := complete(c.Command, args)
+
+	Log("Completion: %s", options)
+	output(options)
+	return true
+}
+
+// complete get a command an command line arguments and returns
+// matching completion options
+func complete(c Command, args []string) (matching []string) {
+	options, _ := c.options(args[:len(args)-1])
+
+	// choose only matching options
+	l := last(args)
+	for _, option := range options {
+		if option.Match(l) {
+			matching = append(matching, option.String())
+		}
+	}
+	return
+}
+
+func getLine() ([]string, bool) {
+	line := os.Getenv(envComplete)
+	if line == "" {
+		return nil, false
+	}
+	return strings.Split(line, " "), true
+}
+
+func last(args []string) (last string) {
+	if len(args) > 0 {
+		last = args[len(args)-1]
+	}
+	return
+}
+
+func output(options []string) {
+	// stdout of program defines the complete options
+	for _, option := range options {
+		fmt.Println(option)
+	}
+}