feat: add m_end position to AST nodes

- Add end line and column (m_end.m_line, m_end.m_col) to AST output
- New AST format: [name, begin_line, begin_col, end_line, end_col, ...children]
- Update format_spec.yue to normalize end positions for comparison
- Add ast_spec.yue tests for AST end position feature

Closes #251

2 files changed, 88 insertions, 1 deletions

diff --git a/spec/outputs/test/ast_spec.lua b/spec/outputs/test/ast_spec.lua
new file mode 100644
index 0000000..bab5b9e
--- /dev/null
+++ b/spec/outputs/test/ast_spec.lua
@@ -0,0 +1,85 @@
+local yue = require("yue")
+return describe("yue.to_ast", function()
+        it("should return AST with end position for simple expression", function()
+                local ast = yue.to_ast("x = 1")
+                assert.is_not_nil(ast)
+                assert.same(ast[1], "File")
+                assert.same(ast[2], 1)
+                assert.same(ast[3], 1)
+                assert.is_number(ast[4])
+                return assert.is_number(ast[5])
+        end)
+        it("should have correct end position for leaf nodes", function()
+                local ast = yue.to_ast("1")
+                assert.is_not_nil(ast)
+                assert.same(ast[1], "File")
+                assert.same(ast[2], 1)
+                assert.same(ast[3], 1)
+                assert.is_number(ast[4])
+                return assert.is_number(ast[5])
+        end)
+        it("should have end position for multi-line code", function()
+                local code = [[x = 1
+y = 2]]
+                local ast = yue.to_ast(code)
+                assert.is_not_nil(ast)
+                assert.same(ast[1], "File")
+                assert.same(ast[2], 1)
+                assert.same(ast[3], 1)
+                return assert.is_true(ast[4] >= 2)
+        end)
+        it("should have end position for function definition", function()
+                local code = [[add = (a, b) ->
+        a + b]]
+                local ast = yue.to_ast(code)
+                assert.is_not_nil(ast)
+                assert.same(ast[1], "File")
+                assert.same(ast[2], 1)
+                assert.same(ast[3], 1)
+                assert.is_number(ast[4])
+                return assert.is_number(ast[5])
+        end)
+        it("should have end position for table literal", function()
+                local ast = yue.to_ast("{a: 1, b: 2}")
+                assert.is_not_nil(ast)
+                assert.same(ast[1], "File")
+                assert.same(ast[2], 1)
+                assert.same(ast[3], 1)
+                assert.is_number(ast[4])
+                return assert.is_number(ast[5])
+        end)
+        it("should have end position for class definition", function()
+                local code = [[class Person
+        new: (@name) =>
+        getName: => @name]]
+                local ast = yue.to_ast(code)
+                assert.is_not_nil(ast)
+                assert.same(ast[1], "File")
+                assert.same(ast[2], 1)
+                assert.same(ast[3], 1)
+                return assert.is_true(ast[4] >= 3)
+        end)
+        it("should return nil and error message for invalid syntax", function()
+                local ast, err = yue.to_ast("if then else")
+                assert.is_nil(ast)
+                return assert.is_string(err)
+        end)
+        it("should support flatten level parameter", function()
+                local ast = yue.to_ast("x = 1", 0)
+                assert.is_not_nil(ast)
+                assert.same(ast[1], "File")
+                assert.is_number(ast[4])
+                return assert.is_number(ast[5])
+        end)
+        return it("should have end position in nested structures", function()
+                local code = "x = [i for i = 1, 10]"
+                local ast = yue.to_ast(code)
+                assert.is_not_nil(ast)
+                assert.same(ast[1], "File")
+                assert.same(ast[2], 1)
+                assert.same(ast[3], 1)
+                assert.is_number(ast[4])
+                assert.is_number(ast[5])
+                return assert.is_true(ast[5] > 1)
+        end)
+end)
diff --git a/spec/outputs/test/format_spec.lua b/spec/outputs/test/format_spec.lua
index c9ea3c2..d38a0ad 100644
--- a/spec/outputs/test/format_spec.lua
+++ b/spec/outputs/test/format_spec.lua
@@ -164,7 +164,9 @@ local rewriteLineCol
 rewriteLineCol = function(item)
         item[2] = 0
         item[3] = 0
-        for i = 4, #item do
+        item[4] = 0
+        item[5] = 0
+        for i = 6, #item do
                 local _exp_0 = type(item[i])
                 if "table" == _exp_0 then
                         if item[i][1] == "comment" then