make assoc accept multiple values, also added a even/odd check for checkargs

hy/compiler.py

@@ -318,7 +318,7 @@ def _raise_wrong_args_number(expression, error):
                                len(expression)))
 
 
-def checkargs(exact=None, min=None, max=None):
+def checkargs(exact=None, min=None, max=None, even=None):
     def _dec(fn):
         def checker(self, expression):
             if exact is not None and (len(expression) - 1) != exact:
@@ -335,6 +335,11 @@ def checkargs(exact=None, min=None, max=None):
                     expression,
                     "`%%s' needs at most %d arguments, got %%d" % (max))
                 
+            is_even = not((len(expression) - 1) % 2)
+            if even is not None and is_even!=even:
+                even_str = "even" if even else "odd"
+                _raise_wrong_args_number(expression, "`%%s' needs an %s number of arguments, got %%d" % (even_str))
+
             return fn(self, expression)
 
         return checker
@@ -1130,15 +1135,20 @@ class HyASTCompiler(object):
             ctx=ast.Load())
 
     @builds("assoc")
-    @checkargs(3)
+    @checkargs(min=3, even=False)
     def compile_assoc_expression(self, expr):
         expr.pop(0)  # assoc
         # (assoc foo bar baz)  => foo[bar] = baz
         target = self.compile(expr.pop(0))
+        ret = target
+        while expr != []:
             key = self.compile(expr.pop(0))
+            try:
                 val = self.compile(expr.pop(0))
+            except IndexError:
+                raise HyCompileError("Key {key} has no value to associate".format(key))
 
-        return target + key + val + ast.Assign(
+            ret += key + val + ast.Assign(
                 lineno=expr.start_line,
                 col_offset=expr.start_column,
                 targets=[
@@ -1149,6 +1159,7 @@ class HyASTCompiler(object):
                         slice=ast.Index(value=key.force_expr),
                         ctx=ast.Store())],
                 value=val.force_expr)
+        return ret
 
     @builds("with_decorator")
     @checkargs(min=1)

tests/native_tests/language.hy

@@ -348,6 +348,11 @@
   (assoc vals "two" "three")
   (assert (= (get vals "two") "three")))
 
+(defn test-multiassoc []
+  "NATIVE: test assoc multiple values"
+  (setv vals {"one" "two"})
+  (assoc vals "two" "three" "four" "five")
+  (assert (and (= (get vals "two") "three") (= (get vals "four") "five"))))
 
 (defn test-pass []
   "NATIVE: Test pass worksish"