Add bash completions generator

.github/workflows/test.yml

@@ -13,7 +13,7 @@ jobs:
       LC_ALL: en_US.UTF-8 # consistent sort order
 
     strategy:
-      matrix: { ruby: ['2.4', '2.5', '2.6', '2.7', '3.0'] }
+      matrix: { ruby: ['2.7', '3.0'] }
 
     steps:
     - name: Checkout code

README.md

@@ -31,6 +31,7 @@ Create beautiful bash scripts from simple YAML configuration
   - [Flag options](#flag-options)
   - [Environment Variable options](#environment-variable-options)
 - [Extensible Scripts](#extensible-scripts)
+- [Bash Completions](#bash-completions)
 - [Real World Examples](#real-world-examples)
 - [Contributing / Support](#contributing--support)
 
@@ -75,13 +76,15 @@ Bahsly is responsible for:
   - Optional or required **option flags** (with or without flag arguments).
   - **Commands** (and subcommands).
   - Standard flags (like **--help** and **--version**).
+- Preventing your script from running unless the command line is valid.
 - Providing you with a place to input your code for each of the functions 
   your tool performs, and merging it back to the final script.
 - Providing you with additional (optional) framework-style, standard
   library functions:
   - **Color output**.
   - **Config file management** (INI format).
   - **YAML parsing**.
+  - **Bash completions**.
   - and more.
 
 
@@ -198,6 +201,7 @@ command and subcommands (under the `commands` definition).
 `commands` | Specify the array of [commands](#command-options). Each command will have its own args and flags. Note: if `commands` is provided, you cannot specify flags or args at the same level.
 `args`     | Specify the array of [positional arguments](#argument-options) this script needs.
 `flags`    | Specify the array of option [flags](#flag-options) this script needs.
+`completions` | Specify an array of additional completion suggestions when used in conjunction with `bashly add comp`. See [Bash Completions](#bash-completions).
 `catch_all` | Specify that this command should allow for additional arbitrary arguments or flags. It can be set in one of three ways:<br>- Set to `true` to just enable it.<br>- Set to a string, to use this string in the usage help text.<br>- Set to a hash containing `label` and `help` keys, to show a detailed help for it when running with `--help`.
 `dependencies` | Specify an array of any required external dependencies (commands). The script execution will be halted with a friendly error unless all dependency commands exist.
 `group`    | In case you have many commands, use this option to specify a caption to display before this command. This option is purely for display purposes, and needs to be specified only for the first command in each group.
@@ -326,6 +330,71 @@ The generated script will execute `git status`.
 See the [extensible-delegate example](examples/extensible-delegate).
 
 
+## Bash Completions
+
+Bashly comes with built-in bash completions generator, provided by the 
+[completely][completely] gem.
+
+By running any of the `bashly add comp` commands, you can add this
+functionality to your script in one of three ways:
+
+- `bashly add comp function` - creates a function in your `./src/lib` directory
+   that echoes a completion script. You can then call this function from any
+   command (for example `yourcli completions`) and your users will be able to 
+   install the completions by running `eval "$(yourcli completions)"`.
+- `bashly add comp script` - creates a standalone completion script that can be
+  sourced or copies to the system's bash completions directory.
+- `bashly add comp yaml` - creates the "raw data" YAML file. This is intended
+  mainly for development purposes.
+
+The bash completions generation is completely automatic, and you will have to 
+rerun the `bashly add comp *` command whenever you change your `bashly.yml` 
+script.
+
+In addition to suggesting subcommands and flags, you can instruct bashly to
+also suggest files, directories, users and more. To do this, add another option
+in your `bashly.yml` on the command you wish to alter:
+
+```yaml
+# bashly.yml
+commands:
+- name: upload
+  help: Upload a file
+  completions: [directory, user]
+
+```
+
+Valid completion additions are:
+
+| Keyword     | Meaning
+|-------------|---------------------
+| `alias`     | Alias names
+| `arrayvar`  | Array variable names
+| `binding`   | Readline key binding names
+| `builtin`   | Names of shell builtin commands
+| `command`   | Command names
+| `directory` | Directory names
+| `disabled`  | Names of disabled shell builtins
+| `enabled`   | Names of enabled shell builtins
+| `export`    | Names of exported shell variables
+| `file`      | File names
+| `function`  | Names of shell functions
+| `group`     | Group names
+| `helptopic` | Help topics as accepted by the help builtin
+| `hostname`  | Hostnames, as taken from the file specified by the HOSTFILE shell variable
+| `job`       | Job names
+| `keyword`   | Shell reserved words
+| `running`   | Names of running jobs
+| `service`   | Service names
+| `signal`    | Signal names
+| `stopped`   | Names of stopped jobs
+| `user`      | User names
+| `variable`  | Names of all shell variables
+
+Note that these are taken from the [Programmable Completion Builtin][compgen], 
+and will simply be added using the `compgen -A action` command.
+
+
 ## Real World Examples
 
 - [Rush][rush] - a Personal Package Manager
@@ -344,3 +413,5 @@ to contribute, feel free to [open an issue][issues].
 [rush]: https://github.com/DannyBen/rush-cli
 [alf]: https://github.com/DannyBen/alf
 [git-changelog]: https://github.com/DannyBen/git-changelog
+[completely]: https://github.com/DannyBen/completely
+[compgen]: https://www.gnu.org/software/bash/manual/html_node/Programmable-Completion-Builtins.html

bashly.gemspec

@@ -15,9 +15,10 @@ Gem::Specification.new do |s|
   s.executables = ['bashly']
   s.homepage    = 'https://github.com/dannyben/bashly'
   s.license     = 'MIT'
-  s.required_ruby_version = ">= 2.3.0"
+  s.required_ruby_version = ">= 2.7.0"
 
   s.add_runtime_dependency 'colsole', '~> 0.6'
+  s.add_runtime_dependency 'completely', '~> 0.1', '>= 0.1.2'
   s.add_runtime_dependency 'mister_bin', '~> 0.7'
   s.add_runtime_dependency 'requires', '~> 0.1'
 end

examples/README.md

@@ -42,3 +42,4 @@ Each of these examples demonstrates one aspect or feature of bashly.
 - [config-ini](config-ini#readme) - using the config (INI) functions
 - [colors](colors#readme) - using the color print feature
 - [yaml](yaml#readme) - using the YAML reading functions
+- [completions](completions#readme) - adding bash completion functionality

examples/completions/README.md

@@ -0,0 +1,164 @@
+# Bash Completions Example
+
+Demonstrates how to build a script that supports bash completions.
+
+This example was generated with:
+
+    $ bashly init
+    $ bashly add comp function
+    $ bashly generate
+
+-----
+
+## `bashly.yml`
+
+```yaml
+name: cli
+help: Sample application with bash completions
+version: 0.1.0
+
+commands:
+- name: completions
+  help: |-
+    Generate bash completions
+    Usage: eval "\$(cli completions)"
+
+- name: download
+  short: d
+  help: Download a file
+  completions: [file]
+
+  args:
+  - name: source
+    required: true
+    help: URL to download from
+  - name: target
+    help: "Target filename (default: same as source)"
+
+  flags:
+  - long: --force
+    short: -f
+    help: Overwrite existing files
+
+  examples:
+  - cli download example.com
+  - cli download example.com ./output -f
+
+  environment_variables:
+  - name: default_target_location
+    help: Set the default location to download to
+
+- name: upload
+  short: u
+  help: Upload a file
+  completions: [directory, user]
+  args:
+  - name: source
+    required: true
+    help: File to upload
+
+  flags:
+  - long: --user
+    short: -u
+    arg: user
+    help: Username to use for logging in
+    required: true
+  - long: --password
+    short: -p
+    arg: password
+    help: Password to use for logging in
+```
+
+## Generated script output
+
+### `$ ./cli`
+
+```shell
+cli - Sample application with bash completions
+
+Usage:
+  cli [command]
+  cli [command] --help | -h
+  cli --version | -v
+
+Commands:
+  completions   Generate bash completions
+  download      Download a file
+  upload        Upload a file
+
+
+
+```
+
+### `$ ./cli -h`
+
+```shell
+cli - Sample application with bash completions
+
+Usage:
+  cli [command]
+  cli [command] --help | -h
+  cli --version | -v
+
+Commands:
+  completions   Generate bash completions
+  download      Download a file
+  upload        Upload a file
+
+Options:
+  --help, -h
+    Show this help
+
+  --version, -v
+    Show version number
+
+
+
+```
+
+### `$ ./cli completions -h`
+
+```shell
+cli completions
+
+  Generate bash completions
+  Usage: eval "$(cli completions)"
+
+Usage:
+  cli completions
+  cli completions --help | -h
+
+Options:
+  --help, -h
+    Show this help
+
+
+
+```
+
+### `$ ./cli completions`
+
+```shell
+#!/usr/bin/env bash
+
+# This bash completions script was generated by
+# completely (https://github.com/dannyben/completely)
+# Modifying it manually is not recommended
+_cli_completions() {
+  local cur=${COMP_WORDS[COMP_CWORD]}
+
+  case "$COMP_LINE" in
+    'cli completions'*) COMPREPLY=($(compgen -W "--help -h" -- "$cur")) ;;
+    'cli download'*) COMPREPLY=($(compgen -A file -W "--force --help -f -h" -- "$cur")) ;;
+    'cli upload'*) COMPREPLY=($(compgen -A directory -A user -W "--help --password --user -h -p -u" -- "$cur")) ;;
+    'cli'*) COMPREPLY=($(compgen -W "--help --version -h -v completions download upload" -- "$cur")) ;;
+  esac
+}
+
+complete -F _cli_completions cli
+
+
+```
+
+
+