Add bash completion

Author: plexus

README.md

@@ -609,29 +609,34 @@ map they receive.
 
 ## Shell completion
 
-There is experimental support for shell tab-completion for zsh. It is bare
-bones, it can complete subcommands and flags, and is aware of nested
+There is experimental support for shell tab-completion for zsh and bash. It is
+bare bones, it can complete subcommands and flags, and is aware of nested
 subcommands, but don't expect it to be perfect. There is no smart completion of
-flag values yes.
+flag values or positional arguments yet, and it's not yet pluggable (specify
+type/completions of values), but it's already helpful.
 
 To get started run the hidden `__licli install-completions` subcommand. This
-will create `~/.zsh/completions/_licli`, and add a section to your `~/.zshrc` to
-autoload it and associate it with the current command.
+will detect your shell, and install the necessary bits, and associate our
+dynamic completion with your specific command. You can add `--zsh` or `--bash`
+to explictly choose which shell to configure.
 
 e.g.
 
 ```
 bin/my_command __licli install-completions
 ```
 
-When calling from Clojure (not Babashka), pass the full path to the executable
-as an argument. You can easily use `realpath` for that.
+When calling from Clojure (not Babashka), we can't derive the script name
+explicitly. Pass the full path to the executable as an argument. You can easily
+use `realpath` for that.
 
 ```
 bin/my_command __licli install-completions `realpath bin/my_command`
 ```
 
-Other shells may come in the future. Contributions to the shell completion are welcome!
+Other shells and smarter completions may come in the future. The current
+implementation is so we have a starting point that can be improved.
+Contributions to the shell completion are welcome!
 
 <!-- opencollective -->
 ## Lambda Island Open Source

resources/lambdaisland/cli/_licli.bash

@@ -0,0 +1,36 @@
+# Bash completion function for lambdaisland/cli
+
+_licli() {
+    local cur prev words cword
+    _init_completion || return
+
+    # Get completion suggestions from the CLI tool
+    local completion_output
+    completion_output="$( ${words[0]} __licli completions -- "${words[@]}" 2>/dev/null )"
+
+    if [ -n "$completion_output" ]; then
+        # Parse the completion output (format: "option:description" or just "option")
+        local -a completions
+        local -A descriptions
+        while IFS= read -r line; do
+            # Extract option and description
+            local option="${line%%:*}"
+            local description="${line#*:}"
+            completions+=( "$option" )
+            descriptions["$option"]="$description"
+        done <<< "$completion_output"
+
+        # Generate completions with compgen
+        COMPREPLY=($(compgen -W "${completions[*]}" -- "$cur"))
+
+        # Show descriptions when multiple options exist
+        if [ ${#COMPREPLY[@]} -gt 1 ]; then
+            echo
+            for option in "${COMPREPLY[@]}"; do
+                printf "%-25s %s\n" "$option" "${descriptions[$option]}"
+            done
+            # Re-print the current command line
+            printf "\n%s" "${COMP_LINE@P}"
+        fi
+    fi
+}

src/lambdaisland/cli/completions.clj

@@ -6,7 +6,7 @@
 
 (declare with-completions)
 
-(defn zsh-completions [cmdspec {:lambdaisland.cli/keys [argv] :as opts}]
+(defn shell-completions [cmdspec {:lambdaisland.cli/keys [argv] :as opts}]
   (let [cmdspec (reduce
                  (fn [cmdspec arg]
                    (let [commands (cmdspec/prepare-cmdpairs (:commands (with-completions cmdspec)))]
@@ -31,8 +31,8 @@
         zshrc-path  (io/file home ".zshrc")
         zshrc       (if (.exists zshrc-path) (slurp zshrc-path) "")]
     (when-not script-name
-      (println "When running via clj/clojure (not babashka), you need to pass the fully qualified of the script as the first argument to __install_zsh_completions")
-      (println "e.g. bin/my_script __install_zsh_completions /full/path/to/bin/my_script")
+      (println "When running via clj/clojure (not babashka), you need to pass the fully qualified of the script as the first argument to install-completions")
+      (println "e.g. bin/my_script __licli install-completions /full/path/to/bin/my_script")
       (System/exit -1))
     (when-not (.exists cdir) (.mkdirs cdir))
     (println "Creating" (str (io/file cdir "_licli")))
@@ -54,8 +54,31 @@
       (spit zshrc-path (str zshrc "\n" stanza)))))
 
 (defn install-bash-completions [opts]
-  (throw (ex-info {} "Not implemented"))
-  )
+  (let [home        (System/getProperty "user.home")
+        script-name (or (System/getProperty "babashka.file") (first (:lambdaisland.cli/argv opts)))
+        bashrc-path (io/file home ".bashrc")
+        bashrc      (if (.exists bashrc-path) (slurp bashrc-path) "")]
+    (when-not script-name
+      (println "When running via clj/clojure (not babashka), you need to pass the fully qualified of the script as the first argument to install-completions")
+      (println "e.g. bin/my_script __licli install-completions /full/path/to/bin/my_script")
+      (System/exit -1))
+    (let [base-name (last (str/split script-name #"/"))
+          stanza    (str
+                     (when-not (re-find #"(?m)^# lambdaisland.cli completions" bashrc)
+                       (str
+                        "\n# lambdaisland.cli completions\n"
+                        "if [ -f " (str (io/file home ".bash_completion.d/_licli.bash")) " ]; then\n"
+                        "    source " (str (io/file home ".bash_completion.d/_licli.bash")) "\n"
+                        "fi\n"))
+                     (str "complete -F _licli " script-name " " "*/" base-name " " base-name "\n"))]
+      (let [cdir (io/file home ".bash_completion.d")]
+        (when-not (.exists cdir) (.mkdirs cdir))
+        (println "Creating" (str (io/file cdir "_licli.bash")))
+        (spit (io/file cdir "_licli.bash")
+              (slurp (io/resource "lambdaisland/cli/_licli.bash"))))
+      (println "Updating" (str bashrc-path) ", adding:")
+      (println stanza)
+      (spit bashrc-path (str bashrc "\n" stanza)))))
 
 (defn install-completions
   "Do the necessary setup to get shell completions. Shell will be guessed from
@@ -81,5 +104,5 @@
             ["completions" {:doc "Generate completions based on partially completed arguments
 
 called by shell functions to do the actual completing."
-                            :command (partial zsh-completions cmdspec)}
+                            :command (partial shell-completions cmdspec)}
              "install-completions" #'install-completions]}]))