Allow get with multiple arguments

When calling get with more than two arguments, treat the rest as indexes
into the expression from the former. That is, (get foo "bar" "baz")
would translate to foo["bar"]["baz"], and so on.

This fixes #362.

Requested-by: Sean B. Palmer <sean@miscoranda.com>
Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>

hy/compiler.py

@@ -1086,18 +1086,25 @@ class HyASTCompiler(object):
         return rimports
 
     @builds("get")
-    @checkargs(2)
+    @checkargs(min=2)
     def compile_index_expression(self, expr):
         expr.pop(0)  # index
-        val = self.compile(expr.pop(0))  # target
-        sli = self.compile(expr.pop(0))  # slice
 
-        return val + sli + ast.Subscript(
+        val = self.compile(expr.pop(0))
-            lineno=expr.start_line,
+        slices, ret = self._compile_collect(expr)
-            col_offset=expr.start_column,
+
-            value=val.force_expr,
+        if val.stmts:
-            slice=ast.Index(value=sli.force_expr),
+            ret += val
-            ctx=ast.Load())
+
+        for sli in slices:
+            val = Result() + ast.Subscript(
+                lineno=expr.start_line,
+                col_offset=expr.start_column,
+                value=val.force_expr,
+                slice=ast.Index(value=sli),
+                ctx=ast.Load())
+
+        return ret + val
 
     @builds("del")
     @checkargs(min=1)

tests/compilers/test_ast.py

@@ -253,7 +253,6 @@ def test_ast_bad_get():
     "Make sure AST can't compile invalid get"
     cant_compile("(get)")
     cant_compile("(get 1)")
-    cant_compile("(get 1 2 3)")
 
 
 def test_ast_good_slice():

tests/native_tests/language.hy

@@ -129,7 +129,16 @@
 (defn test-index []
   "NATIVE: Test that dict access works"
   (assert (= (get {"one" "two"} "one") "two"))
-  (assert (= (get [1 2 3 4 5] 1) 2)))
+  (assert (= (get [1 2 3 4 5] 1) 2))
+  (assert (= (get {"first" {"second" {"third" "level"}}}
+                  "first" "second" "third")
+             "level"))
+  (assert (= (get ((fn [] {"first" {"second" {"third" "level"}}}))
+                  "first" "second" "third")
+             "level"))
+  (assert (= (get {"first" {"second" {"third" "level"}}}
+                  ((fn [] "first")) "second" "third")
+             "level")))
 
 
 (defn test-lambda []