Fix AST to_str

CHANGELOG.md

@@ -18,6 +18,10 @@ backward incompatible changes will start to apply when the projects goes 1.0
 
 ## [Unreleased]
 
+### Fixed
+- Fix AST `to_str` in the context of syntactic sugar (BNF extensions).
+
+
 ## [0.16.0] (released: 2022-07-16)
 
 ### Added

parglare/grammar.py

@@ -1694,8 +1694,14 @@ def visit(n, subresults, depth):
                                                         n._pg_children_names[i],
                                                         subresult)
                                        for (i, subresult) in enumerate(subresults)]))
+                    elif isinstance(n, list):
+                        s = '{}[\n{}\n{}]'.format(
+                            indent,
+                            '\n'.join(['{}{}'.format(indent, el)
+                                       for el in subresults]),
+                            indent)
                     else:
-                        s = str(n)
+                        s = repr(n)
                     return s
 
                 return visitor(self, ast_tree_iterator, visit)
@@ -1966,4 +1972,8 @@ def __repr__(cls):
 
 
 def ast_tree_iterator(root):
-    return iter(root._pg_children) if hasattr(root, '_pg_children') else iter([])
+    if hasattr(root, '_pg_children'):
+        return iter(root._pg_children)
+    if isinstance(root, list):
+        return iter(root)
+    return iter([])

tests/func/parsing/test_to_str.py

@@ -55,11 +55,48 @@ def test_ast_to_str():
 
     result = parser.parse('1 2 3 3 3 4 2')
     print(result.to_str())
-    assert result.to_str().strip() == '''
+    assert result.to_str().strip() == """
 S [0->13]
   second=Second [2->3]
-    val=2
-  third=['3', '3', '3']
+    val='2'
+  third=    [
+    '3'
+    '3'
+    '3'
+    ]
   fourth=Fourth [10->13]
     val=Second [12->13]
-      val=2'''.strip()
+      val='2'""".strip()
+
+
+def test_ast_to_str_with_bnf_extensions():
+    """
+    Tests `to_str` with lists returned by BNF extensions.
+    """
+    grammar = r"""
+    S: "1" second=Second third=Third+ fourth=Fourth;
+    Second: val="2";
+    Third: val="3";
+    Fourth: "4" val=Second;
+    """
+
+    g = Grammar.from_string(grammar)
+    parser = Parser(g)
+
+    result = parser.parse('1 2 3 3 3 4 2')
+    print(result.to_str())
+    assert result.to_str().strip() == """
+S [0->13]
+  second=Second [2->3]
+    val='2'
+  third=    [
+    Third [4->5]
+      val='3'
+    Third [6->7]
+      val='3'
+    Third [8->9]
+      val='3'
+    ]
+  fourth=Fourth [10->13]
+    val=Second [12->13]
+      val='2'""".strip()