Address relative import with 3 dots. Closes #1052.

parser/src/python.lalrpop

@@ -218,14 +218,19 @@ ImportStatement: ast::LocatedStatement = {
 };
 
 ImportFromLocation: (usize, Option<String>) = {
-    <dots: "."*> <name:DottedName> => {
-        (dots.len(), Some(name))
+    <dots: ImportDots*> <name:DottedName> => {
+        (dots.iter().sum(), Some(name))
     },
-    <dots: "."+> => {
-        (dots.len(), None)
+    <dots: ImportDots+> => {
+        (dots.iter().sum(), None)
     },
 };
 
+ImportDots: usize = {
+    "..." => 3,
+    "." => 1,
+};
+
 ImportAsNames: Vec<ast::ImportSymbol> = {
     <i:Comma<ImportPart<Identifier>>> => i,
     "(" <i:Comma<ImportPart<Identifier>>> ")" => i,

tests/snippets/ast_snippet.py

@@ -28,3 +28,13 @@ assert 'Lt' in str(n.body[0].value.ops[0])
 assert 'Gt' in str(n.body[0].value.ops[1])
 assert n.body[0].value.comparators[0].n == 4
 assert n.body[0].value.comparators[1].n == 5
+
+
+n = ast.parse('from ... import a\n')
+print(n)
+i = n.body[0]
+assert i.level == 3
+assert i.module is None
+assert i.names[0].name == 'a'
+assert i.names[0].asname is None
+

vm/src/stdlib/ast.rs

@@ -222,8 +222,8 @@ fn statement_to_ast(
 
 fn alias_to_ast(vm: &VirtualMachine, alias: &ast::ImportSymbol) -> PyResult<AstNodeRef> {
     Ok(node!(vm, alias, {
-        symbol => vm.ctx.new_str(alias.symbol.to_string()),
-        alias => optional_string_to_py_obj(vm, &alias.alias)
+        name => vm.ctx.new_str(alias.symbol.to_string()),
+        asname => optional_string_to_py_obj(vm, &alias.alias)
     }))
 }