Infer the class of string and coll literals

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ### master (unreleased)
 
+- Infer the class string and coll literals, giving more accurate completions for those.
+
 ### 0.4.1 (2023-08-23)
 
 - [#33](https://github.com/alexander-yakushev/compliment/issues/33): Demunge

src/compliment/sources/class_members.clj

@@ -105,9 +105,11 @@
                     (:tag (meta (get (set (bindings-from-context context ns)) form))))]
         ;; We have a tag - try to resolve the class from it.
         (resolve-class ns tag)
-        ;; Otherwise, try to resolve symbol to a Var.
+        ;; Otherwise, try to resolve symbol to a Var,
+        ;; or literal to class.
         (or (utils/var->class ns form)
-            (utils/invocation-form->class ns form))))))
+            (utils/invocation-form->class ns form)
+            (utils/literal->class form))))))
 
 (defn members-candidates
   "Returns a list of Java non-static fields and methods candidates."
@@ -222,7 +224,7 @@
       (if (static? c)
         (let [full-name (.getName c)]
           (if (cache (.getName c))
-            (recur (update-in cache [full-name] conj c) r)
+            (recur (update cache full-name conj c) r)
             (recur (assoc cache full-name [c]) r)))
         (recur cache r))
       (swap! static-members-cache assoc class cache))))

src/compliment/sources/local_bindings.clj

@@ -41,7 +41,8 @@
   (when bound-to
     (when-let [found (or (-> bound-to meta :tag)
                          (utils/var->class ns bound-to)
-                         (utils/invocation-form->class ns bound-to))]
+                         (utils/invocation-form->class ns bound-to)
+                         (utils/literal->class bound-to))]
       (if (class? found)
         (-> ^Class found .getName symbol)
         found))))

src/compliment/utils.clj

@@ -267,3 +267,11 @@ Note that should always have the same value, regardless of OS."
                                       (ns-resolve ns (first form)))]
     (when (var? var-from-invocation)
       (-> var-from-invocation meta :tag))))
+
+(defn literal->class
+  "Extracts the class from a literal.
+  This is meant to support interop on strings and Clojure collections."
+  [form]
+  (when (or (string? form)
+            (coll? form))
+    (class form)))

test/compliment/sources/t_class_members.clj

@@ -207,3 +207,28 @@
 
   (fact "static class members have docs"
     (src/static-member-doc "Integer/parseInt" (-ns)) => (checker string?)))
+
+(deftest literals-inference-test
+  (fact "Has around 19 candidates (give or take, varies per JDK),
+which indicates that the members are an exact match against the class of `[]`"
+    (let [c (count (src/members-candidates "." (-ns) (ctx/cache-context
+                                                      "(__prefix__ [])")))]
+      (< 17 c 21))
+    =>
+    truthy)
+
+
+  (fact "A docstring is offered for the previous query"
+    (src/members-doc ".assocN" (-ns)) => (checker string?))
+
+  (fact "Has around 50 candidates (give or take, varies per JDK),
+which indicates that the members are an exact match against the class of `\"\"`"
+    (let [c (count (src/members-candidates "." (-ns) (ctx/cache-context
+                                                      "(__prefix__ \"\")")))]
+      (< 34 c 52))
+    =>
+    truthy)
+
+  (fact "A docstring is offered for the previous query"
+    (src/members-doc ".codePointBefore" (-ns))
+    => (checker string?)))

test/compliment/sources/t_local_bindings.clj

@@ -33,7 +33,19 @@
     (map (comp :tag meta)
          (src/bindings-from-context (ctx/parse-context '(let [a (string/trim "a")] __prefix__))
                                     (-ns)))
-    => (just [`String])))
+    => (just [`String]))
+
+  (fact "The class of a given binding can be identified by the class of a string literal"
+    (map (comp :tag meta)
+         (src/bindings-from-context (ctx/parse-context '(let [a ""] __prefix__))
+                                    (-ns)))
+    => (just [`String]))
+
+  (fact "The class of a given binding can be identified by the class of a vector literal"
+    (map (comp :tag meta)
+         (src/bindings-from-context (ctx/parse-context '(let [a []] __prefix__))
+                                    (-ns)))
+    => (just ['clojure.lang.PersistentVector])))
 
 (deftest local-bindings
   (defmacro ^{:completion/locals :let} like-let [& _])