Rewrite-clj now understands #! comments

Fixes #145

Author: lread

CHANGELOG.adoc

@@ -16,6 +16,8 @@ For a list of breaking changes see link:#v1-breaking[breaking changes].
 
 === Unreleased
 
+* rewrite-clj now understands the `#!` comment, a construct often used in scripts https://github.com/clj-commons/rewrite-clj/issues/145[#145]
+
 === v1.0.594-alpha
 
 * rewrite-clj now explicitly depends on the minimum version of Clojure required, v1.9.0, rather than v1.10.3 https://github.com/clj-commons/rewrite-clj/issues/142[#142]

src/rewrite_clj/node.cljc

@@ -210,18 +210,25 @@
 (defn comment-node
   "Create node representing a comment with text `s`.
 
-   `s` should:
-   - not specify the first leading semicolon
-   - usually include the trailing newline character, otherwise subsequent nodes will be on the comment line
+   You may optionally specify a `prefix` of `\";\"` or `\"#!\"`, defaults is `\";\"`.
+
+   Argument `s`:
+   - must not include the `prefix`
+   - usually includes the trailing newline character, otherwise subsequent nodes will be on the comment line
 
    ```Clojure
    (require '[rewrite-clj.node :as n])
 
    (-> (n/comment-node \"; my comment\\n\")
        n/string)
    ;; => \";; my comment\\n\"
+
+   (-> (n/comment-node \"#!\" \"/usr/bin/env bb\\n\")
+       n/string)
+   ;; => \"#!/usr/bin/env bb\\n\"
    ```"
-  [s] (rewrite-clj.node.comment/comment-node s))
+  ([s] (rewrite-clj.node.comment/comment-node s))
+  ([prefix s] (rewrite-clj.node.comment/comment-node prefix s)))
 
 ;; DO NOT EDIT FILE, automatically imported from: rewrite-clj.node.comment
 (defn comment?

src/rewrite_clj/node/comment.cljc

@@ -5,17 +5,17 @@
 
 ;; ## Node
 
-(defrecord CommentNode [s]
+(defrecord CommentNode [prefix s]
   node/Node
   (tag [_node] :comment)
   (node-type [_node] :comment)
   (printable-only? [_node] true)
   (sexpr* [_node _opts]
     (throw (ex-info "unsupported operation" {})))
   (length [_node]
-    (+ 1 (count s)))
+    (+ (count prefix) (count s)))
   (string [_node]
-    (str ";" s))
+    (str prefix s))
 
   Object
   (toString [node]
@@ -28,20 +28,29 @@
 (defn comment-node
   "Create node representing a comment with text `s`.
 
-   `s` should:
-   - not specify the first leading semicolon
-   - usually include the trailing newline character, otherwise subsequent nodes will be on the comment line
+   You may optionally specify a `prefix` of `\";\"` or `\"#!\"`, defaults is `\";\"`.
+
+   Argument `s`:
+   - must not include the `prefix`
+   - usually includes the trailing newline character, otherwise subsequent nodes will be on the comment line
 
    ```Clojure
    (require '[rewrite-clj.node :as n])
 
    (-> (n/comment-node \"; my comment\\n\")
        n/string)
    ;; => \";; my comment\\n\"
+
+   (-> (n/comment-node \"#!\" \"/usr/bin/env bb\\n\")
+       n/string)
+   ;; => \"#!/usr/bin/env bb\\n\"
    ```"
-  [s]
-  {:pre [(re-matches #"[^\r\n]*[\r\n]?" s)]}
-  (->CommentNode s))
+  ([s]
+   (comment-node ";" s))
+  ([prefix s]
+   {:pre [(and (re-matches #"[^\r\n]*[\r\n]?" s)
+               (or (= prefix ";") (= prefix "#!")))]}
+   (->CommentNode prefix s)))
 
 (defn comment?
   "Returns true if `node` is a comment."

src/rewrite_clj/parser/core.cljc

@@ -1,6 +1,6 @@
 (ns ^:no-doc rewrite-clj.parser.core
   (:require ;; using internal node nses rather than public rewrite-clj.node
-            ;; allows us to use rewrite-clj to generate code for import-vars target nses 
+            ;; allows us to use rewrite-clj to generate code for import-vars target nses
             [rewrite-clj.node.comment :refer [comment-node]]
             [rewrite-clj.node.fn :refer [fn-node]]
             [rewrite-clj.node.meta :refer [meta-node raw-meta-node]]
@@ -98,7 +98,7 @@
 (defmethod parse-next* :comment
   [#?(:cljs ^not-native reader :default reader)]
   (reader/ignore reader)
-  (comment-node (reader/read-include-linebreak reader)))
+  (comment-node ";" (reader/read-include-linebreak reader)))
 
 ;; ### Special Values
 
@@ -123,12 +123,17 @@
   (reader/unread reader \#)
   (parse-token reader))
 
+(defn- parse-shebang-comment [reader]
+  (reader/ignore reader)
+  (comment-node "#!" (reader/read-include-linebreak reader)))
+
 (defmethod parse-next* :sharp
   [#?(:cljs ^not-native reader :default reader)]
   (reader/ignore reader)
   (case (reader/peek reader)
     nil (reader/throw-reader reader "Unexpected EOF.")
-    \# (read-symbolic-value reader) 
+    \# (read-symbolic-value reader)
+    \! (parse-shebang-comment reader)
     \{ (set-node (parse-delim reader \}))
     \( (fn-node (parse-delim reader \)))
     \" (regex-node (parse-regex reader))

test/rewrite_clj/node/coercer_test.cljc

@@ -20,7 +20,7 @@
       ;; numbers
 
       ;; note that we do have an integer-node, but rewrite-clj never parses to it
-      ;; so we never coerce to it either 
+      ;; so we never coerce to it either
       3                      :token      :token
       3N                     :token      :token
       3.14                   :token      :token
@@ -159,6 +159,7 @@
            (is (= ?tag (node/tag n)))
            (is (= ?type (protocols/node-type n))))
       ";; comment"      :comment        :comment
+      "#! comment"      :comment        :comment
       "#(+ 1 %)"        :fn             :fn
       ":my-kw"          :token          :keyword
       "^:m1 [1 2 3]"    :meta           :meta

test/rewrite_clj/node/generators.cljc

@@ -8,9 +8,10 @@
 
 (def comment-node
   (gen/fmap
-   (fn [[text eol]]
-     (node/comment-node (str text eol)))
+   (fn [[prefix text eol]]
+     (node/comment-node prefix (str text eol)))
    (gen/tuple
+    (gen/elements [";" "#!"])
     (gen/such-that
      #(re-matches #"[^\r\n]*" %)
      gen/string-ascii)

test/rewrite_clj/node_test.cljc

@@ -15,6 +15,7 @@
           (is (= ?expected-sexpr-able? (n/sexpr-able? n))))
       ","               :comma          :comma              false
       "; comment"       :comment        :comment            false
+      "#! comment"      :comment        :comment            false
       "@deref"          :deref          :deref              true
       "#(fn %1)"        :fn             :fn                 true
       ":my-kw"          :token          :keyword            true

test/rewrite_clj/parser_test.cljc

@@ -318,7 +318,10 @@
     ";"
     ";;"
     ";\n"
-    ";;\n"))
+    ";;\n"
+    "#!shebang comment\n"
+    "#! this is a comment"
+    "#!\n"))
 
 (deftest t-parsing-auto-resolve-keywords
   (are [?s ?sexpr-default ?sexpr-custom]
@@ -345,7 +348,7 @@
     "#:abc   {:x 1, :y 1}"
     {:abc/x 1, :abc/y 1}
 
-    "#:abc  ,,, \n\n {:x 1 :y 2}" 
+    "#:abc  ,,, \n\n {:x 1 :y 2}"
     {:abc/x 1, :abc/y 2}
 
     "#:foo{:kw 1, :n/kw 2, :_/bare 3, 0 4}"
@@ -391,7 +394,7 @@
     {:?_current-ns_?/a {:?_current-ns_?/b 1}}
     {:booya.fooya/a {:booya.fooya/b 1}}))
 
-(deftest parsing-auto-resolve-ns-alias-maps 
+(deftest parsing-auto-resolve-ns-alias-maps
   (are [?s ?sexpr-default ?sexpr-custom]
        (let [n (p/parse-string ?s)]
          (is (= :namespaced-map (node/tag n)))