[feature] tab complete (#173)

Gopkg.toml

@@ -30,10 +30,6 @@
   branch = "master"
   name = "github.com/hashicorp/hcl"
 
-[[constraint]]
-  name = "github.com/pkg/errors"
-  branch = "master"
-
 [[constraint]]
   name = "github.com/hashicorp/terraform"
   version = "0.11.7"

README.md

@@ -55,6 +55,32 @@ The basic workflow is –
 2. run `fogg apply` to code generate
 3. use the generated Makefiles to run your Terraform commands
 
+### Enabling shell autocompletion
+
+#### bash
+
+##### Linux
+```
+# Might need to install bash-completion on CentOS
+yum install bash-completion
+# install completion
+echo "source <(fogg completion bash)" >> ~/.bashrc
+```
+
+##### Mac
+```
+## If running Bash 3.2 included with macOS
+brew install bash-completion
+## or, if running Bash 4.1+
+brew install bash-completion@2
+
+# install completion
+fogg completion bash > $(brew --prefix)/etc/bash_completion.d/fogg
+```
+
+#### zsh
+You can add the file generated by `fogg completion zsh` to a directory in your $fpath.
+
 ## Design Principles
 
 ### Convention over Configuration

cmd/completion.go

@@ -0,0 +1,37 @@
+package cmd
+
+import (
+	"os"
+
+	"github.com/spf13/cobra"
+)
+
+var completionCmd = &cobra.Command{
+	Use:          "completion",
+	Short:        "",
+	SilenceUsage: true,
+}
+
+var bashCmd = &cobra.Command{
+	Use:   "bash",
+	Short: "Generates bash completion",
+	Long:  "Generates bash completion",
+	RunE: func(cmd *cobra.Command, args []string) error {
+		return rootCmd.GenBashCompletion(os.Stdout)
+	},
+}
+
+var zshCmd = &cobra.Command{
+	Use:   "zsh",
+	Short: "Generates zsh completion",
+	Long:  "Generates zsh completion",
+	RunE: func(cmd *cobra.Command, args []string) error {
+		return rootCmd.GenZshCompletion(os.Stdout)
+	},
+}
+
+func init() {
+	rootCmd.AddCommand(completionCmd)
+	completionCmd.AddCommand(bashCmd)
+	completionCmd.AddCommand(zshCmd)
+}

cmd/root.go

@@ -25,6 +25,7 @@ var rootCmd = &cobra.Command{
 	SilenceUsage: true,
 }
 
+// Execute executes the rootCmd
 func Execute() {
 	red := color.New(color.FgRed).SprintFunc()
 

test

@@ -0,0 +1,27 @@
+#compdef fogg
+
+case $state in
+  level1)
+    case $words[1] in
+      fogg)
+        _arguments '1: :(apply completion help init plan version)'
+      ;;
+      *)
+        _arguments '*: :_files'
+      ;;
+    esac
+  ;;
+  level2)
+    case $words[2] in
+      completion)
+        _arguments '2: :(bash zsh)'
+      ;;
+      *)
+        _arguments '*: :_files'
+      ;;
+    esac
+  ;;
+  *)
+    _arguments '*: :_files'
+  ;;
+esac