[oil-language] Got lists and subscripts working.

Had to hack in an 'any' type to ASDL.

asdl/meta.py

@@ -109,5 +109,9 @@ def LookupFieldType(self, field_name):
     'int': IntType(),
     'bool': BoolType(),
     'dict': DictType(),
+
+    # TODO: This is a hack for the Oil expression evaluator.  We're not doing
+    # any dynamic or static checking now.
+    'any': StrType(),
 }
 

oil_lang/expr_eval.py

@@ -55,6 +55,10 @@ def EvalRHS(self, node):
     if node.tag == expr_e.Const:
       return int(node.c.val)
 
+    if node.tag == expr_e.Var:
+      val = self.mem.GetVar(node.name.val)
+      return val.obj
+
     if node.tag == expr_e.Binary:
       left = self.EvalRHS(node.left)
       right = self.EvalRHS(node.right)
@@ -70,4 +74,14 @@ def EvalRHS(self, node):
 
       raise NotImplementedError(node.op.id)
 
+    if node.tag == expr_e.List:
+      return [self.EvalRHS(e) for e in node.elts]
+
+    if node.tag == expr_e.Subscript:
+      collection = self.EvalRHS(node.collection)
+
+      # TODO: handle multiple indices like a[i, j]
+      index = self.EvalRHS(node.indices[0])
+      return collection[index]
+
     raise NotImplementedError(node.__class__.__name__)

oil_lang/testdata/hello.osh

@@ -6,8 +6,14 @@ var x = 1 + 2*3
 
 echo "x: $x"
 
+var mylist = [1, 2, 3]
+
+var y = mylist[1] * 10
+
+echo "y: $y"
+
 
 # TODO:
 # - Mutate variables
-# - Demo lists and dicts
+# - Demo dicts
 

osh/cmd_exec.py

@@ -772,7 +772,7 @@ def _Dispatch(self, node, fork_external):
 
       lval = self.expr_ev.EvalLHS(node.lhs)
       py_val = self.expr_ev.EvalRHS(node.rhs)
-      val = value.Str(str(py_val))
+      val = value.Obj(py_val)
       flags = ()
       self.mem.SetVar(lval, val, flags, scope_e.LocalOnly)
 

osh/runtime.asdl

@@ -30,6 +30,8 @@ module runtime
   | Str(string s)
   | StrArray(string* strs)
   | AssocArray(dict d)
+    -- A Python-style object.  'any' is not currently type checked.
+  | Obj(any obj)
 
   -- For Oil?
   -- | ArrayInt(int* array_int)

osh/word_eval.py

@@ -52,6 +52,9 @@ def _ValueToPartValue(val, quoted):
     # TODO: Is this correct?
     return part_value.Array(val.d.values())
 
+  elif val.tag == value_e.Obj:
+    return part_value.String(repr(val.obj), quoted, not quoted)
+
   else:
     # Undef should be caught by _EmptyStrOrError().
     raise AssertionError(val.__class__.__name__)