🐐 Escape sequences

tests.py

@@ -1080,6 +1080,63 @@ class TestInterpolation(unittest.TestCase):
     run_test(self, source, nodes, value, output)
 
 
+# --- Escape sequences ---
+
+escape_tests = [
+  # \n → newline
+  ('"hello\\nworld"',
+    Program([], [ExpressionStatement(String("hello\nworld"))]),
+    ValStr("hello\nworld")),
+  # \t → tab
+  ('"col\\tcol"',
+    Program([], [ExpressionStatement(String("col\tcol"))]),
+    ValStr("col\tcol")),
+  # \r → carriage return
+  ('"line\\rover"',
+    Program([], [ExpressionStatement(String("line\rover"))]),
+    ValStr("line\rover")),
+  # \\ → literal backslash
+  ('"back\\\\slash"',
+    Program([], [ExpressionStatement(String("back\\slash"))]),
+    ValStr("back\\slash")),
+  # \" → literal double quote
+  ('"say \\"salve\\""',
+    Program([], [ExpressionStatement(String('say "salve"'))]),
+    ValStr('say "salve"')),
+  # \' → literal single quote in single-quoted string
+  ("'it\\'s'",
+    Program([], [ExpressionStatement(String("it's"))]),
+    ValStr("it's")),
+  # \n in single-quoted string
+  ("'hello\\nworld'",
+    Program([], [ExpressionStatement(String("hello\nworld"))]),
+    ValStr("hello\nworld")),
+  # escape inside interpolated string
+  ('DESIGNA name VT "Roma"\n"salve\\n{name}"',
+    Program([], [
+      Designa(ID("name"), String("Roma")),
+      ExpressionStatement(InterpolatedString([String("salve\n"), ID("name")]))
+    ]), ValStr("salve\nRoma")),
+  # DIC with newline escape
+  ('DIC("hello\\nworld")',
+    Program([], [ExpressionStatement(BuiltIn("DIC", [String("hello\nworld")]))]),
+    ValStr("hello\nworld"), "hello\nworld\n"),
+  # multiple escapes in one string
+  ('"\\t\\n\\\\"',
+    Program([], [ExpressionStatement(String("\t\n\\"))]),
+    ValStr("\t\n\\")),
+  # unknown escapes pass through (regex backrefs)
+  ('"\\1\\2"',
+    Program([], [ExpressionStatement(String("\\1\\2"))]),
+    ValStr("\\1\\2")),
+]
+
+class TestEscapeSequences(unittest.TestCase):
+  @parameterized.expand(escape_tests)
+  def test_escape(self, source, nodes, value, output=""):
+    run_test(self, source, nodes, value, output)
+
+
 # --- Comparison operators ---
 
 comparison_tests = [