add shebang support (#8)

README.md

@@ -66,9 +66,11 @@ You may also download a binary from [Github](https://github.com/borkdude/babashk
 ## Usage
 
 ``` shellsession
-bb [ --help ] [ -i ] [ -o ] [ -io ] [ --version ] [ expression ]
+bb [ --help ] [ -i ] [ -o ] [ -io ] [ --version ] [ -f <file> ] [ expression ]
 ```
 
+Type `bb --help` to see a full explanation of the options.
+
 There is one special variable, `*in*`, which is the input read from stdin. The
 input is read as EDN by default. If the `-i` flag is provided, then the input is
 read as a string which is then split on newlines. The output is printed as EDN
@@ -79,12 +81,21 @@ The current version can be printed with `bb --version`.
 
 Currently only the following special forms/macros are supported: anonymous
 function literals like `#(%1 %2)`, `quote`, `do`,`if`, `when`, `let`, `and`,
-`or`, `->`, `->>`, `as->`.
+`or`, `->`, `->>`, `as->`. Anonymous functions literals are allowed with
+currently up to three positional arguments.
 
-The `clojure.core` functions are accessible without a namespace alias. Those in
-`clojure.string` are accessed through the alias `str`, like:
-`str/includes?`. Those in `clojure.set` using the alias `set`, like:
-`set/difference`.
+The `clojure.core` functions are accessible without a namespace alias.
+
+The following Clojure namespaces are required by default and only available
+through the aliases:
+
+- `clojure.string` aliased as `str`
+- `clojure.set` aliased as `set`
+- `clojure.java.shell` aliases as `shell` (only `sh` is available)
+
+From Java the following is available:
+
+- `System`: `getProperty`, `getProperties`, `getenv`
 
 Examples:
 
@@ -102,9 +113,6 @@ $ bb '(filterv :foo *in*)' <<< '[{:foo 1} {:bar 2}]'
 [{:foo 1}]
 ```
 
-Anonymous functions literals are allowed with currently up to three positional
-arguments.
-
 ``` shellsession
 $ bb '(#(+ %1 %2 %3) 1 2 *in*)' <<< 3
 6
@@ -115,17 +123,34 @@ $ ls | bb -i '(filterv #(re-find #"reflection" %) *in*)'
 ["reflection.json"]
 ```
 
-Shell commands can be executed using `csh` which is an alias for
-`clojure.java.shell/sh`:
-
 ``` shellsession
-$ bb '(run! #(csh "touch" (str "/tmp/test/" %)) (range 100))'
+$ bb '(run! #(shell/sh "touch" (str "/tmp/test/" %)) (range 100))'
 $ ls /tmp/test | bb -i '*in*'
 ["0" "1" "10" "11" "12" "13" "14" "15" "16" "17" "18" "19" "2" "20" "21" ...]
 ```
 
 More examples can be found in the [gallery](#gallery).
 
+## Running a file
+
+Babashka expressions may be executed from a file using `-f` or `--file`:
+
+``` shellsession
+bb -f script.clj
+```
+
+Using `bb` with a shebang also works:
+
+``` shellsession
+$ cat script.clj
+#!/usr/bin/env bb -f
+
+(+ 1 2 3)
+
+$ ./script.clj
+6
+```
+
 ## Test
 
 Test on the JVM:

src/babashka/main.clj

@@ -3,7 +3,7 @@
   (:require
    [clojure.edn :as edn]
    [clojure.java.io :as io]
-   [clojure.java.shell :as cjs]
+   [clojure.java.shell :as shell]
    [clojure.string :as str :refer [starts-with?]]
    [sci.core :as sci])
   (:gen-class))
@@ -38,12 +38,15 @@
         raw-out (boolean (or (get opts "-o")
                              (get opts "-io")))
         println? (boolean (get opts "--println"))
-        help? (boolean (get opts "--help"))]
+        help? (boolean (get opts "--help"))
+        file (first (or (get opts "-f")
+                        (get opts "--file")))]
     {:version version
      :raw-in raw-in
      :raw-out raw-out
      :println? println?
-     :help? help?}))
+     :help? help?
+     :file file}))
 
 (defn parse-shell-string [s]
   (str/split s #"\n"))
@@ -69,13 +72,46 @@
   -i: read shell input into a list of strings instead of reading EDN.
   -o: write shell output instead of EDN.
   -io: combination of -i and -o.
+  --file or -f: read expression from file instead of argument
 "))
 
+(defn read-file [file]
+  (as-> (slurp file) x
+    ;; remove hashbang
+    (str/replace x #"^#!.*" "")
+    (format "(do %s)" x)))
+
+(defn get-env
+  ([] (System/getenv))
+  ([s] (System/getenv s)))
+
+(defn get-property
+  ([s]
+   (System/getProperty s))
+  ([s d]
+   (System/getProperty s d)))
+
+(defn get-properties []
+  (System/getProperties))
+
+(def bindings
+  {'run! run!
+   'shell/sh shell/sh
+   'csh shell/sh ;; backwards compatibility, deprecated
+   'pmap pmap
+   'print print
+   'pr-str pr-str
+   'prn prn
+   'println println
+   'System/getenv get-env
+   'System/getProperty get-property
+   'System/getProperties get-properties})
+
 (defn main
   [& args]
   (or
    (let [{:keys [:version :raw-in :raw-out :println?
-                 :help?]} (parse-opts args)]
+                 :help? :file]} (parse-opts args)]
      (second
       (cond version
             [(print-version) 0]
@@ -84,19 +120,18 @@
             :else
             (try
               [(let [exprs (drop-while #(str/starts-with? % "-") args)
-                     _ (when (not= (count exprs) 1)
+                     _ (when-not (or (= 1 (count exprs)) file)
                          (throw (Exception. ^String usage-string)))
-                     expr (last args)
+                     expr (if file (read-file file) (last args))
                      in (delay (let [in (slurp *in*)]
                                  (if raw-in
                                    (parse-shell-string in)
                                    (read-edn in))))
                      res (sci/eval-string
                           expr
-                          {:bindings {(with-meta '*in*
-                                        {:sci/deref! true}) in
-                                      'run! run!
-                                      'csh cjs/sh}})]
+                          {:bindings (assoc bindings
+                                            (with-meta '*in*
+                                              {:sci/deref! true}) in)})]
                  (if raw-out
                    (if (coll? res)
                      (doseq [l res]

test/babashka/main_test.clj

@@ -63,3 +63,9 @@
 (deftest input-test
   (testing "bb doesn't wait for input if *in* isn't used"
     (is (= "2\n" (with-out-str (main/main "(inc 1)"))))))
+
+(deftest System-test
+  (let [res (bb nil "-f" "test/babashka/scripts/System.bb")]
+    (is (= "bar" (second res)))
+    (doseq [s res]
+      (is (not-empty s)))))

test/babashka/scripts/System.bb

@@ -0,0 +1,5 @@
+[(System/getProperty "user.dir")
+ (System/getProperty "foo" "bar")
+ (System/getenv "HOME")
+ (System/getProperties)
+ (System/getenv)]

test/babashka/test_utils.clj

@@ -7,14 +7,18 @@
 
 (defn bb-jvm [input & args]
   (with-out-str
-    (with-in-str input
-      (apply main/main args))))
+    (if input
+      (with-in-str input
+        (apply main/main args))
+      (apply main/main input args))))
 
 (defn bb-native [input & args]
   (let-programs [bb "./bb"]
     (binding [sh/*throw* false]
-      (apply bb (conj (vec args)
-                       {:in input})))))
+      (if input
+        (apply bb (conj (vec args)
+                        {:in input}))
+        (apply bb input args)))))
 
 (def bb
   (case (System/getenv "BABASHKA_TEST_ENV")