Match, match_case, and MatchValue

src/latexify/codegen/function_codegen.py

@@ -713,6 +713,35 @@ def visit_IfExp(self, node: ast.IfExp) -> str:
         latex += self.visit(current_expr)
         return latex + r", & \mathrm{otherwise} \end{array} \right."
 
+    def visit_Match(self, node: ast.Match) -> str:
+        """Visit a match node"""
+        latex = r"\left\{ \begin{array}{ll}"
+        subject_latex = self.visit(node.subject)
+        for match_case in node.cases:
+            if not (
+                len(match_case.body) == 1 and isinstance(match_case.body[0], ast.Return)
+            ):
+                raise exceptions.LatexifyNotSupportedError(
+                    "Match cases must have exactly 1 return statement."
+                )
+            true_latex = self.visit(match_case.body[0])
+            cond_latex = self.visit(match_case.pattern)
+            latex += (
+                true_latex
+                + r", & \mathrm{if} \ "
+                + subject_latex
+                + cond_latex
+                + r" \\ "
+            )
+
+        latex += r"\end{array} \right."
+        return latex
+
+    def visit_MatchValue(self, node: ast.MatchValue) -> str:
+        """Visit a MatchValue node"""
+        latex = self.visit(node.value)
+        return " = " + latex
+
     def _reduce_stop_parameter(self, node: ast.expr) -> ast.expr:
         """Adjusts the stop expression of the range.
 

src/latexify/codegen/function_codegen_test.py

@@ -915,6 +915,84 @@ def test_use_set_symbols_compare(code: str, latex: str) -> None:
     assert function_codegen.FunctionCodegen(use_set_symbols=True).visit(tree) == latex
 
 
+@test_utils.require_at_least(10)
+def test_matchvalue() -> None:
+    tree = ast.parse(
+        textwrap.dedent(
+            """
+            match x:
+                case 0:
+                    return 1
+            """
+        )
+    ).body[0]
+
+    assert (
+        FunctionCodegen().visit(tree)
+        == r"\left\{ \begin{array}{ll}1, & \mathrm{if} \ x = 0 \\ \end{array} \right."
+    )
+
+
+@test_utils.require_at_least(10)
+def test_multiple_matchvalue() -> None:
+    tree = ast.parse(
+        textwrap.dedent(
+            """
+            match x:
+                case 0:
+                    return 1
+                case 1:
+                    return 2
+            """
+        )
+    ).body[0]
+
+    assert (
+        FunctionCodegen().visit(tree)
+        == r"\left\{ \begin{array}{ll}1, & \mathrm{if} \ x = 0 \\"
+        + r" 2, & \mathrm{if} \ x = 1 \\ \end{array} \right."
+    )
+
+
+@test_utils.require_at_least(10)
+def test_matchvalue_no_return() -> None:
+    tree = ast.parse(
+        textwrap.dedent(
+            """
+            match x:
+                case 0:
+                    x = 5
+            """
+        )
+    ).body[0]
+
+    with pytest.raises(
+        exceptions.LatexifyNotSupportedError,
+        match=r"^Match cases must have exactly 1 return statement\.$",
+    ):
+        FunctionCodegen().visit(tree)
+
+
+@test_utils.require_at_least(10)
+def test_matchvalue_mutliple_statements() -> None:
+    tree = ast.parse(
+        textwrap.dedent(
+            """
+            match x:
+                case 0:
+                    x = 5
+                    return 1
+            """
+        )
+    ).body[0]
+
+    with pytest.raises(
+        exceptions.LatexifyNotSupportedError,
+        match=r"^Match cases must have exactly 1 return statement\.$",
+    ):
+        FunctionCodegen().visit(tree)
+
+
 @pytest.mark.parametrize(
     "code,latex",
     [