align associative

.gitignore

@@ -8,3 +8,4 @@ pom.xml.asc
 .lein-*
 .nrepl-port
 reports
+*.cpcache

README.md

@@ -154,6 +154,13 @@ selectively enabled or disabled:
   other references in the `ns` forms at the top of your namespaces.
   Defaults to false.
 
+* `:align-associative?` -
+  true if cljfmt should left align the values of maps and binding
+  special forms (let, loop, binding). This will convert 
+  `{:foo 1\n:barbaz 2}` to `{:foo    1\n :barbaz 2}`
+  and `(let [foo 1\n barbaz 2])` to `(let [foo    1\n      barbaz 2])`.
+  Defaults to false.
+
 You can also configure the behavior of cljfmt:
 
 * `:paths` - determines which directories to include in the

cljfmt/src/cljfmt/core.cljc

@@ -71,9 +71,73 @@
        (not (namespaced-map? (z/up* zloc)))
        (element? (z/right* zloc))))
 
+(def ^:private binding-keywords #{"doseq" "let" "loop" "binding" "with-open"
+                                  "go-loop" "if-let" "when-some" "if-some" "for"
+                                  "with-local-vars" "with-redefs"})
+
+(defn ks->max-length [ks]
+  (if (empty? ks)
+    0
+    (->> ks
+         (apply max-key (comp count str))
+         str
+         count)))
+
+(defn- aligner [zloc max-length align?]
+  (cond
+    (zero? max-length)  (z/up zloc)
+    (z/rightmost? zloc) (z/up zloc)
+    align?              (let [to-add   (->> zloc
+                                            z/sexpr
+                                            str
+                                            count
+                                            (- max-length))
+                              new-zloc (z/insert-space-right zloc to-add)]
+                         (aligner (z/right new-zloc) max-length false))
+    :else               (aligner (z/right zloc) max-length true)))
+
+(defn- align-binding [zloc]
+  (let [se         (z/sexpr zloc)
+        ks         (take-nth 2 se)
+        max-length (ks->max-length ks)
+        bindings (z/down zloc)]
+    (if bindings
+      (aligner bindings max-length true)
+      zloc)))
+
+(defn- align-map [zloc]
+  (let [se         (z/sexpr zloc)
+        ks         (keys se)
+        max-length (ks->max-length ks)
+        kvs        (z/down zloc)]
+    (if kvs
+      (aligner kvs max-length true)
+      zloc)))
+
+(defn- binding? [zloc]
+  (and (z/vector? zloc)
+       (-> zloc z/sexpr count even?)
+       (->> zloc
+            z/left
+            z/string
+            binding-keywords)))
+
+(defn align-map-or-binding [zloc]
+  (cond
+    (binding? zloc) (align-binding zloc)
+    (z/map? zloc)   (align-map zloc)
+    :else zloc))
+
+(defn- align-associative? [zloc]
+  (or (binding? zloc)
+      (z/map? zloc)))
+
 (defn insert-missing-whitespace [form]
   (transform form edit-all missing-whitespace? z/insert-space-right))
 
+(defn align-associative [form]
+  (transform form edit-all align-associative? align-map-or-binding))
+
 (defn- space? [zloc]
   (= (z/tag zloc) :whitespace))
 
@@ -492,6 +556,7 @@
    :remove-surrounding-whitespace?        true
    :remove-trailing-whitespace?           true
    :split-keypairs-over-multiple-lines?   false
+   :align-associative?                    false
    :sort-ns-references?                   false
    :indents   default-indents
    :alias-map {}})
@@ -512,6 +577,8 @@
            remove-surrounding-whitespace)
          (cond-> (:insert-missing-whitespace? opts)
            insert-missing-whitespace)
+         (cond-> (:align-associative? opts)
+           align-associative)
          (cond-> (:remove-multiple-non-indenting-spaces? opts)
            remove-multiple-non-indenting-spaces)
          (cond-> (:indentation? opts)

cljfmt/test/cljfmt/core_test.cljc

@@ -1336,3 +1336,90 @@
         "   ^{:x 1} b"
         "   [c]))"]
        {:sort-ns-references? true})))
+
+(deftest test-align-associative
+  (testing "sanity"
+    (is (reformats-to?
+          ["(def x 1)"]
+          ["(def x 1)"]
+          {:align-associative? true})))
+  (testing "no op 0"
+    (is (reformats-to?
+          ["(let [x 1"
+           "      y 2])"]
+          ["(let [x 1"
+           "      y 2])"]
+          {:align-associative? true})))
+  (testing "no op 1"
+    (is (reformats-to?
+          ["(let [x 1])"]
+          ["(let [x 1])"]
+          {:align-associative? true})))
+  (testing "empty"
+    (is (reformats-to?
+          ["(let [])"]
+          ["(let [])"]
+          {:align-associative? true})))
+  (testing "simple binding"
+    (is (reformats-to?
+          ["(let [x 1"
+           "      longer 2])"]
+          ["(let [x      1"
+           "      longer 2])"]
+          {:align-associative? true})))
+  (testing "simple map"
+    (is (reformats-to?
+          ["{:x 1"
+           " :longer 2}"]
+          ["{:x      1"
+           " :longer 2}"]
+          {:align-associative? true})))
+  (testing "nested simple map"
+    (is (reformats-to?
+          ["{:x {:x 1}"
+           " :longer 2}"]
+          ["{:x      {:x 1}"
+           " :longer 2}"]
+          {:align-associative? true})))
+  (testing "nested align map"
+    (is (reformats-to?
+          ["{:x {:x 1"
+           "     :longer 2}"
+           " :longer 2}"]
+          ["{:x      {:x      1"
+           "          :longer 2}"
+           " :longer 2}"]
+          {:align-associative? true})))
+  (testing "nested align binding"
+    (is (reformats-to?
+          ["(let [x (let [x 1"
+           "     longer 2])"
+           " longer 2])"]
+          ["(let [x      (let [x      1"
+           "                   longer 2])"
+           "      longer 2])"]
+          {:align-associative? true})))
+  (testing "align many map"
+    (is (reformats-to?
+          ["{:a 1"
+           " :longer 2"
+           " :b 3}"]
+          ["{:a      1"
+           " :longer 2"
+           " :b      3}"]
+          {:align-associative? true})))
+  (testing "binding align preserves comments"
+    (is (reformats-to?
+          ["(let [a 1 ;; comment"
+           "      longer 2])"]
+          ["(let [a      1 ;; comment"
+           "      longer 2])"]
+          {:align-associative? true}
+          )))
+  (testing "map align preserves comments"
+    (is (reformats-to?
+          ["{:a 1 ;; comment"
+           " :longer 2}"]
+          ["{:a      1 ;; comment"
+           " :longer 2}"]
+          {:align-associative? true}))))