Merge pull request #11 from Flexiana/feat/underscore-plus-alias

Add _+_ as terse alias for infix

Author: jiriknesl

src/infix/core.clj

@@ -139,7 +139,7 @@
 
 (defmacro infix
   "Transform infix expressions into Clojure forms.
-  
+
   Example:
     (infix a + b * c) => (+ a (* b c))
     (infix x => x * x) => (fn [x] (* x x))"
@@ -154,6 +154,15 @@
         parser/parse-infix
         compiler/compile-postfix)))
 
+(defmacro _+_
+  "Terse alias for `infix` — operand-operator-operand notation.
+
+  Example:
+    (_+_ a + b * c) => (+ a (* b c))
+    (_+_ x => x * x) => (fn [x] (* x x))"
+  [& expr]
+  `(infix ~@expr))
+
 (defn- process-binding-pairs
   "Process infix-let binding pairs, transforming RHS to infix."
   [bindings]

test/infix/alias_test.clj

@@ -0,0 +1,28 @@
+(ns infix.alias-test
+  (:require [clojure.test :refer [deftest is testing]]
+            [infix.core :refer [_+_]]))
+
+(deftest underscore-plus-alias
+  (testing "_+_ behaves identically to infix for arithmetic"
+    (is (= 7 (_+_ 3 + 4)))
+    (is (= 14 (_+_ 2 * 3 + 4 * 2)))
+    (is (= 25 (_+_ 5 * 5))))
+
+  (testing "_+_ supports comparison and boolean operators"
+    (is (= true (_+_ 5 > 3)))
+    (is (= true (_+_ 1 < 2 and 2 < 3))))
+
+  (testing "_+_ supports arrow-lambda syntax"
+    (is (= 25 ((_+_ x => x * x) 5)))
+    (is (= 7 ((_+_ (x y) => x + y) 3 4))))
+
+  (testing "_+_ supports nested fn(args) calls"
+    (is (= 3 (_+_ count([1 2 3]))))
+    (is (= 4 (_+_ count([1 2 3]) + 1))))
+
+  (testing "_+_ supports redundant grouping"
+    (is (= 7 (_+_ ((((3 + 4))))))))
+
+  (testing "macroexpansion produces equivalent form to infix"
+    (is (= (macroexpand '(infix.core/infix 3 + 4))
+           (macroexpand '(infix.core/_+_ 3 + 4))))))