Add optional type argument to the :array special

doc/special-syntax.md

@@ -8,15 +8,19 @@ The first group are used for SQL expressions. The second (last group) are used p
 
 ## array
 
-Accepts a single argument, which is expected to evaluate to
-a sequence, and produces `ARRAY[?, ?, ..]` for the elements
-of that sequence (as SQL parameters):
+Accepts a single argument, which is expected to evaluate to a sequence,
+with an optional second argument specifying the type of the array,
+and produces `ARRAY[?, ?, ..]` for the elements of that sequence (as SQL parameters):
 
 ```clojure
 (require '[honey.sql :as sql])
 
 (sql/format-expr [:array (range 5)])
 ;;=> ["ARRAY[?, ?, ?, ?, ?]" 0 1 2 3 4]
+(sql/format-expr [:array (range 3) :text])
+;;=> ["ARRAY[?, ?, ?]::TEXT[]" 0 1 2]
+(sql/format-expr [:array [] :integer])
+;;=> ["ARRAY[]::INTEGER[]"]
 ```
 
 > Note: you cannot provide a named parameter as the argument for `:array` because the generated SQL depends on the number of elements in the sequence, so the following throws an exception:

src/honey/sql.cljc

@@ -1437,10 +1437,11 @@
                              (str/join ", " (map format-single-column spec))
                              ">")])
     :array
-    (fn [_ [arr]]
+    (fn [_ [arr type]]
       ;; allow for (unwrap arr) here?
-      (let [[sqls params] (format-expr-list arr)]
-        (into [(str "ARRAY[" (str/join ", " sqls) "]")] params)))
+      (let [[sqls params] (format-expr-list arr)
+            type-str (when type (str "::" (sql-kw type) "[]"))]
+        (into [(str "ARRAY[" (str/join ", " sqls) "]" type-str)] params)))
     :between
     (fn [_ [x a b]]
       (let [[sql-x & params-x] (format-expr x {:nested true})

test/honey/sql_test.cljc

@@ -278,7 +278,12 @@
                   :columns [:baz]
                   :values [[[:array :?vals]]]}
                  {:params {:vals [1 2 3 4]}})
-         ["INSERT INTO foo (baz) VALUES (ARRAY[?, ?, ?, ?])" 1 2 3 4])))
+         ["INSERT INTO foo (baz) VALUES (ARRAY[?, ?, ?, ?])" 1 2 3 4]))
+  (testing "typed array"
+    (is (= (format {:select [[[:array [] :integer]]]})
+           ["SELECT ARRAY[]::INTEGER[]"]))
+    (is (= (format {:select [[[:array [1 2] :text]]]})
+           ["SELECT ARRAY[?, ?]::TEXT[]" 1 2]))))
 
 (deftest union-test
   ;; UNION and INTERSECT subexpressions should not be parenthesized.