help

src/babashka/main.clj

@@ -81,8 +81,12 @@
 (defn print-version []
   (println (str "babashka v" version)))
 
+(def bb-edn
+  (atom nil))
 
-(defn print-help []
+(defn print-help [command-line-args]
+  (if (empty? command-line-args)
+    (do
       (println (str "Babashka v" version))
       ;; (println (str "sci v" (str/trim (slurp (io/resource "SCI_VERSION")))))
       (println)
@@ -132,7 +136,17 @@ If the first argument is not any of the above options, then it treated as a file
 Everything after that is bound to *command-line-args*.
 
 Use -- to separate script command line args from bb command line args.
-"))
+")
+      [nil 0]) ;; end do
+    (let [k (first command-line-args)
+          k (keyword (subs k 1))
+          task (get-in @bb-edn [:tasks k])
+          help-text (:task/help task)]
+      (if help-text
+        [(println help-text) 0]
+        [(println "No help found for task:" k) 1])
+      ,)) ;; end if
+  ,) ;; end defn
 
 (defn print-describe []
   (println
@@ -362,9 +376,6 @@ Use -- to separate script command line args from bb command line args.
     (println msg)
     {:exec (fn [] [nil exit])}))
 
-(def bb-edn
-  (atom nil))
-
 (defn parse-opts [options]
   (let [fst (when options (first options))
         key? (when fst (str/starts-with? fst ":"))
@@ -384,7 +395,8 @@ Use -- to separate script command line args from bb command line args.
                          ("--clojure" ":clojure") (assoc opts-map :clojure true
                                                          :command-line-args (rest options))
                          ("--version" ":version") {:version true}
-                         ("--help" "-h" "-?") {:help? true}
+                         ("--help" "-h" "-?" ":help") {:help true
+                                                       :command-line-args (rest options)}
                          ("--verbose")(recur (next options)
                                              (assoc opts-map
                                                     :verbose? true))
@@ -475,7 +487,7 @@ Use -- to separate script command line args from bb command line args.
                          (let [options (next options)]
                            (recur (next options)
                                   (update opts-map :expressions (fnil conj []) (first options))))
-                         ("--main", "-m")
+                         ("--main", "-m", ":main")
                          (let [options (next options)]
                            (recur (next options)
                                   (assoc opts-map :main (first options))))
@@ -542,7 +554,7 @@ Use -- to separate script command line args from bb command line args.
                   sci/ns @sci/ns]
       (let [{version-opt :version
              :keys [:shell-in :edn-in :shell-out :edn-out
-                    :help? :file :command-line-args
+                    :help :file :command-line-args
                     :expressions :stream?
                     :repl :socket-repl :nrepl
                     :verbose? :classpath
@@ -671,8 +683,8 @@ Use -- to separate script command line args from bb command line args.
                 (second
                  (cond version-opt
                        [(print-version) 0]
-                       help?
+                       help
-                       [(print-help) 0]
+                       (print-help command-line-args)
                        describe?
                        [(print-describe) 0]
                        repl [(repl/start-repl! sci-ctx) 0]

test-resources/bb.edn

@@ -42,6 +42,13 @@
                                    :__ :print-hello]}
          ,
 
+         ;;;; help
+         :cool-task {:task/type :babashka
+                     :args ["-e" "(+ 1 2 3)"]
+                     :task/help "Usage: bb :cool-task
+
+Sum up the numbers 1, 2 and 3."}
+         ,
          ;;;; context (not implemented)
          ;; the problem with this is the DSL nature which is very opiniated and
          ;; maybe not so nice to learn for people who only want to write Clojure

test/babashka/bb_edn_test.clj

@@ -4,7 +4,8 @@
    [babashka.fs :as fs]
    [babashka.test-utils :as test-utils]
    [clojure.edn :as edn]
-   [clojure.test :as test :refer [deftest is testing]]))
+   [clojure.test :as test :refer [deftest is testing]]
+   [clojure.string :as str]))
 
 (defn bb [& args]
   (edn/read-string
@@ -94,3 +95,14 @@
   (with-config {:tasks {:describe {:task/type :babashka
                                    :args ["-e" "(+ 1 2 3)"]}}}
     (is (= 6 (bb :describe)))))
+
+(deftest help-task-test
+  (with-config {:tasks {:cool-task {:task/type :babashka
+                                    :args ["-e" "(+ 1 2 3)"]
+                                    :task/help "Usage: bb :cool-task
+
+Addition is a pretty advanced topic.  Let us start with the identity element
+0. ..."}}}
+    (is (str/includes? (apply test-utils/bb nil
+                              (map str [:help :cool-task]))
+                       "Usage: bb :cool-task"))))