fix #696: add let* special form

CHANGELOG.md

@@ -16,6 +16,7 @@ For a list of breaking changes, check [here](#breaking-changes)
 - [#693](https://github.com/babashka/sci/issues/693): extend protocol to IRecord doesn't work on SCI records
 - [#695](https://github.com/babashka/sci/issues/695): `(identical? [] [])` works
 - [#700](https://github.com/babashka/sci/issues/700): loop doesn't expand in fully qualified let
+- [#696](https://github.com/babashka/sci/issues/696): add let* special form
 
 ## v0.3.2
 

src/sci/impl/analyzer.cljc

@@ -46,7 +46,7 @@
 
 ;; derived from (keys (. clojure.lang.Compiler specials))
 ;; (& monitor-exit case* try reify* finally loop* do letfn* if clojure.core/import* new deftype* let* fn* recur set! . var quote catch throw monitor-enter def)
-(def special-syms '#{try finally do if new recur quote catch throw def . var set!})
+(def special-syms '#{try finally do if new recur quote catch throw def . var set! let*})
 
 (defn- throw-error-with-location [msg node]
   (utils/throw-error-with-location msg node {:phase "analysis"}))
@@ -457,7 +457,7 @@
                                     (fn [iden->invoke-idx]
                                       (if (contains? iden->invoke-idx ob)
                                         iden->invoke-idx
-                                        (assoc iden->invoke-idx ob (+ #_arity (count iden->invoke-idx))))))))
+                                        (assoc iden->invoke-idx ob (count iden->invoke-idx)))))))
         closure-idx (get-in new-cb (conj parents :syms ob))]
     closure-idx))
 
@@ -1220,6 +1220,7 @@
                         ;; every sub expression
                         do (return-do ctx expr (rest expr))
                         let (analyze-let ctx expr)
+                        let* (analyze-let* ctx expr (second expr) (nnext expr))
                         (fn fn*) (analyze-fn ctx expr false)
                         def (analyze-def ctx expr)
                         ;; NOTE: defn / defmacro aren't implemented as normal macros yet

test/sci/core_test.cljc

@@ -166,7 +166,9 @@
                   '(let [x 3] (f) (f) x) {:bindings {'f #(swap! a inc)}})
                  @a)))))
   (testing "nested lets"
-    (is (= [2 1] (eval* "(let [x 1] [(let [x 2] x) x])")))))
+    (is (= [2 1] (eval* "(let [x 1] [(let [x 2] x) x])"))))
+  (testing "let*"
+    (is (= [2 1] (eval* "(let* [x 1] [(let* [x 2] x) x])")))))
 
 (deftest closure-test
   (testing "closure"