- Made a small modification to how variants/sums are created, to ensure variants for which there is only 1 possible value just compile down to that value (into the same way that 1-tuples are compiled down to their single value).

3 files changed, 48 insertions, 40 deletions

diff --git a/src/lux/analyser.clj b/src/lux/analyser.clj
index e261420c3..25bb09b6d 100644
--- a/src/lux/analyser.clj
+++ b/src/lux/analyser.clj
@@ -19,24 +19,28 @@
                           [parser :as &&a-parser])))
 
 ;; [Utils]
-(defn analyse-variant+ [analyser exo-type ident values]
+(defn analyse-variant+ [analyse exo-type ident values]
   (|do [[module tag-name] (&/normalize ident)
         idx (&&module/tag-index module tag-name)
         group (&&module/tag-group module tag-name)
         :let [is-last? (= idx (dec (&/|length group)))]]
-    (|case exo-type
-      (&/$VarT id)
-      (|do [? (&type/bound? id)]
-        (if (or ? (&&/type-tag? module tag-name))
-          (&&lux/analyse-variant analyser (&/V &/$Right exo-type) idx is-last? values)
-          (|do [wanted-type (&&module/tag-type module tag-name)
-                [[variant-type variant-cursor] variant-analysis] (&&/cap-1 (&&lux/analyse-variant analyser (&/V &/$Left wanted-type) idx is-last? values))
-                _ (&type/check exo-type variant-type)]
-            (return (&/|list (&&/|meta exo-type variant-cursor variant-analysis))))))
-
-      _
-      (&&lux/analyse-variant analyser (&/V &/$Right exo-type) idx is-last? values)
-      )))
+    (if (= 1 (&/|length group))
+      (|do [_cursor &/cursor]
+        (analyse exo-type (&/T [_cursor (&/V &/$TupleS values)])))
+      (|case exo-type
+        (&/$VarT id)
+        (|do [? (&type/bound? id)]
+          (if (or ? (&&/type-tag? module tag-name))
+            (&&lux/analyse-variant analyse (&/V &/$Right exo-type) idx is-last? values)
+            (|do [wanted-type (&&module/tag-type module tag-name)
+                  [[variant-type variant-cursor] variant-analysis] (&&/cap-1 (&&lux/analyse-variant analyse (&/V &/$Left wanted-type) idx is-last? values))
+                  _ (&type/check exo-type variant-type)]
+              (return (&/|list (&&/|meta exo-type variant-cursor variant-analysis))))))
+
+        _
+        (&&lux/analyse-variant analyse (&/V &/$Right exo-type) idx is-last? values)
+        ))
+    ))
 
 (defn ^:private add-loc [meta ^String msg]
   (if (.startsWith msg "@")
diff --git a/src/lux/analyser/lux.clj b/src/lux/analyser/lux.clj
index fba8ea15b..8d2736f9d 100644
--- a/src/lux/analyser/lux.clj
+++ b/src/lux/analyser/lux.clj
@@ -198,8 +198,9 @@
         (|case exo-type*
           (&/$SumT _)
           (|do [vtype (&type/sum-at idx exo-type*)
-                :let [is-last?* (if (nil? is-last?)
-                                  (= idx (dec (&/|length (&type/flatten-sum exo-type*))))
+                :let [num-variant-types (&/|length (&type/flatten-sum exo-type*))
+                      is-last?* (if (nil? is-last?)
+                                  (= idx (dec num-variant-types))
                                   is-last?)]
                 =value (&/with-attempt
                          (analyse-variant-body analyse vtype ?values)
@@ -214,9 +215,10 @@
                                         'analyse-variant " " idx " " is-last? " " is-last?* " " (&type/show-type exo-type) " " (&type/show-type _exo-type)
                                         " " (->> ?values (&/|map &/show-ast) (&/|interpose " ") (&/fold str "")))))))
                 _cursor &/cursor]
-            (return (&/|list (&&/|meta exo-type _cursor
-                                       (&/V &&/$variant (&/T [idx is-last?* =value]))
-                                       ))))
+            (if (= 1 num-variant-types)
+              (return (&/|list =value))
+              (return (&/|list (&&/|meta exo-type _cursor (&/V &&/$variant (&/T [idx is-last?* =value])))))
+              ))
 
           (&/$UnivQ _)
           (|do [$var &type/existential
diff --git a/src/lux/compiler/case.clj b/src/lux/compiler/case.clj
index 1b0e023eb..c7a7145f8 100644
--- a/src/lux/compiler/case.clj
+++ b/src/lux/compiler/case.clj
@@ -116,27 +116,29 @@
           (.visitJumpInsn Opcodes/GOTO $target))))
 
     (&a-case/$VariantTestAC ?tag ?count ?test)
-    (let [$variant-else (new Label)]
-      (doto writer
-        (.visitTypeInsn Opcodes/CHECKCAST "[Ljava/lang/Object;")
-        (.visitInsn Opcodes/DUP)
-        (.visitLdcInsn (int ?tag))
-        (.visitMethodInsn Opcodes/INVOKESTATIC "lux/LuxUtils" "sum_get" "([Ljava/lang/Object;I)Ljava/lang/Object;")
-        (.visitInsn Opcodes/DUP)
-        (.visitInsn Opcodes/ACONST_NULL)
-        (.visitJumpInsn Opcodes/IF_ACMPEQ $variant-else)
-        (-> (doto (compile-match ?test $value-then $value-else)
-              (.visitLabel $value-then)
-              (.visitInsn Opcodes/POP)
-              (.visitJumpInsn Opcodes/GOTO $target)
-              (.visitLabel $value-else)
-              (.visitInsn Opcodes/POP)
-              (.visitJumpInsn Opcodes/GOTO $else))
-            (->> (let [$value-then (new Label)
-                       $value-else (new Label)])))
-        (.visitLabel $variant-else)
-        (.visitInsn Opcodes/POP)
-        (.visitJumpInsn Opcodes/GOTO $else)))
+    (if (= 1 ?count)
+      (compile-match ?test $target $else)
+      (let [$variant-else (new Label)]
+        (doto writer
+          (.visitTypeInsn Opcodes/CHECKCAST "[Ljava/lang/Object;")
+          (.visitInsn Opcodes/DUP)
+          (.visitLdcInsn (int ?tag))
+          (.visitMethodInsn Opcodes/INVOKESTATIC "lux/LuxUtils" "sum_get" "([Ljava/lang/Object;I)Ljava/lang/Object;")
+          (.visitInsn Opcodes/DUP)
+          (.visitInsn Opcodes/ACONST_NULL)
+          (.visitJumpInsn Opcodes/IF_ACMPEQ $variant-else)
+          (-> (doto (compile-match ?test $value-then $value-else)
+                (.visitLabel $value-then)
+                (.visitInsn Opcodes/POP)
+                (.visitJumpInsn Opcodes/GOTO $target)
+                (.visitLabel $value-else)
+                (.visitInsn Opcodes/POP)
+                (.visitJumpInsn Opcodes/GOTO $else))
+              (->> (let [$value-then (new Label)
+                         $value-else (new Label)])))
+          (.visitLabel $variant-else)
+          (.visitInsn Opcodes/POP)
+          (.visitJumpInsn Opcodes/GOTO $else))))
     ))
 
 (defn ^:private separate-bodies [patterns]