more flexible AST\walk

1 files changed, 34 insertions, 13 deletions

diff --git a/spec/ast_spec.moon b/spec/ast_spec.moon
index cfb64cf..80fbb56 100644
--- a/spec/ast_spec.moon
+++ b/spec/ast_spec.moon
@@ -1,15 +1,36 @@
 import Atom, Xpr from require 'ast'
 
-describe 'Xpr', ->
-  it 'can be walked', ->
-    aa = Xpr { '', (Atom '1', '', 1), '' }
-    ab = Xpr { '', (Atom '2', '', 2), '' }
-    ac = Xpr { '', (Atom '3', '', 3), '' }
-    b = Xpr { '', aa, ' ', ab, '' }
-
-    root = Xpr { '', ac, ' ', b, '' }, 'naked'
-
-    iter = root\walk_sexpr!
-    for res in *{ ac, aa, ab, b }
-      assert.is.equal res, iter!
-    assert.is.nil iter!
+describe 'AST', ->
+  describe 'can be walked', ->
+    a1 = Atom '1', '', 1
+    a2 = Atom '2', '', 2
+    a3 = Atom '3', '', 3
+    x1 = Xpr { '', a1, '' }
+    x21 = Xpr { '', a2, '' }
+    x22 = Xpr { '', a3, '' }
+    x2 = Xpr { '', x21, ' ', x22, '' }
+
+    root = Xpr { '', x1, ' ', x2, '' }, 'naked'
+
+    assert_yields = (expected_order, iter) ->
+      for val in *expected_order
+        got_typ, got_val = iter!
+        assert.is.equal val.type, got_typ
+        assert.is.equal val, got_val
+      assert.is.nil iter!
+
+    it 'inside-out', ->
+      assert_yields { a1, x1, a2, x21, a3, x22, x2, root }, root\walk 'inout'
+
+    it 'inside-out, skipping the root', ->
+      assert_yields { a1, x1, a2, x21, a3, x22, x2 }, root\walk 'inout', false
+
+    it 'outside-in', ->
+      assert_yields { root, x1, a1, x2, x21, a2, x22, a3 }, root\walk 'outin'
+
+    it 'outside-in, skipping the root', ->
+      assert_yields { x1, a1, x2, x21, a2, x22, a3 }, root\walk 'outin', false
+
+    it 'errors when direction is wrong or absent', ->
+      assert.has.errors -> root\walk!
+      assert.has.errors -> root\walk 'backandforth'