Proposed opt quoted-when

Proposing a new option, quoted-when, to allow overriding the default
opinionated quoting when quoting has been disabled.

This can be useful, for example, if a user wants to selectively quote
fields like only quoting reserved words.

doc/options.md

@@ -22,6 +22,7 @@ All options may be omitted. The default behavior of each option is described in
 * `:numbered` -- a Boolean indicating whether to generate numbered placeholders in the generated SQL (`$1`, `$2`, etc) or positional placeholders (`?`); the default is `false` (positional placeholders); this option was added in 2.4.962,
 * `:params` -- a hash map providing values for named parameters, identified by names (keywords or symbols) that start with `?` in the DSL; the default is that any such named parameters will have `nil` values,
 * `:quoted` -- a Boolean indicating whether or not to quote (strop) SQL entity names (table and column names); the default is `nil` -- alphanumeric SQL entity names are not quoted but (as of 2.3.928) "unusual" SQL entity names are quoted; a `false` value turns off all quoting,
+* `:quoted-when` -- a function overriding the default behavior of when to quote entities when `:quoted false` (default). Function should take single argument - the entity/part being quoted - and return a boolean indicator whether to quote it or not.
 * `:quoted-snake` -- a Boolean indicating whether or not quoted and string SQL entity names should have `-` replaced by `_`; the default is `false` -- quoted and string SQL entity names are left exactly as-is,
 * `:values-default-columns` -- a sequence of column names that should have `DEFAULT` values instead of `NULL` values if used in a `VALUES` clause with no associated matching value in the hash maps passed in; the default behavior is for such missing columns to be given `NULL` values.
 

src/honey/sql.cljc

@@ -120,6 +120,7 @@
 ; should become defonce
 (def ^:private default-dialect (atom (:ansi @dialects)))
 (def ^:private default-quoted (atom nil))
+(def ^:private default-quoted-when (atom nil))
 (def ^:private default-quoted-snake (atom nil))
 (def ^:private default-inline (atom nil))
 (def ^:private default-checking (atom :none))
@@ -130,6 +131,7 @@
 ;; functions harder than necessary:
 (def ^:private ^:dynamic *clause-order* default-clause-order)
 (def ^:private ^:dynamic *quoted* @default-quoted)
+(def ^:private ^:dynamic *quoted-when* @default-quoted-when)
 (def ^:private ^:dynamic *quoted-snake* @default-quoted-snake)
 (def ^:private ^:dynamic *inline* @default-inline)
 (def ^:private ^:dynamic *params* nil)
@@ -265,9 +267,10 @@
                           ;; characters in entity, then quote it:
                           (nil? *quoted*)
                           (fn opt-quote [part]
-                            (if (re-find #"^[A-Za-z0-9_]+$" part)
-                              part
-                              (dialect-q part)))
+                            (let [quote? (or *quoted-when* #(not (re-find #"^[A-Za-z0-9_]+$" %)))]
+                              (if (quote? part)
+                                (dialect-q part)
+                                part)))
                           :else
                           identity)
         parts-fn    (or (:parts-fn *dialect*)
@@ -2031,6 +2034,9 @@
                                true
                                :else
                                @default-quoted)
+               *quoted-when* (if (contains? opts :quoted-when)
+                                (:quoted-when opts)
+                                @default-quoted-when)
                *quoted-snake* (if (contains? opts :quoted-snake)
                                 (:quoted-snake opts)
                                 @default-quoted-snake)
@@ -2073,10 +2079,11 @@
   * :inline
   * :numbered
   * :quoted
+  * :quoted-when
   * :quoted-snake
   Note that calling `set-dialect!` can override the default for `:quoted`."
   [opts]
-  (let [unknowns (dissoc opts :checking :inline :numbered :quoted :quoted-snake)]
+  (let [unknowns (dissoc opts :checking :inline :numbered :quoted :quoted-when :quoted-snake)]
     (when (seq unknowns)
       (throw (ex-info (str (str/join ", " (keys unknowns))
                            " are not options that can be set globally.")
@@ -2089,6 +2096,8 @@
       (reset! default-numbered (:numbered opts)))
     (when (contains? opts :quoted)
       (reset! default-quoted (:quoted opts)))
+    (when (contains? opts :quoted-when)
+      (reset! default-quoted-when (:quoted-when opts)))
     (when (contains? opts :quoted-snake)
       (reset! default-quoted-snake (:quoted-snake opts)))))
 

test/honey/sql/helpers_test.cljc

@@ -263,6 +263,10 @@
          (sql/format {:select [:foo [[:cast :bar [:char 10]]]]} {:dialect :mysql
                                                                  :inline true}))))
 
+(deftest test-quoting
+  (is (= ["SELECT foo, \"bar\""]
+         (sql/format {:select [:foo :bar]} {:quoted-when #(some #{%} ["bar"])})))) ;; Example showing only quoting reserved words
+
 (deftest test-value
   (is (= ["INSERT INTO foo (bar) VALUES (?)" {:baz "my-val"}]
          (->