add batch of string ops (#20826)

Summary:
First batch of https://github.com/pytorch/pytorch/issues/20769, handles `isupper`, `islower`, `isdigit`, `isspace`, `isalnum`, `isalpha`, `upper`, `lower`
Pull Request resolved: https://github.com/pytorch/pytorch/pull/20826

Differential Revision: D15459166

Pulled By: eellison

fbshipit-source-id: 0ed908022475e27011803cc4af7cf393a4312783

test/test_jit.py

@@ -12079,14 +12079,29 @@ a")
 
         self.checkScript(fn, ("abcde",))
 
-    def test_str_cmp(self):
-        def test(a, b):
+    def test_str_ops(self):
+        def test_str_is(s):
+            # type: (str) -> Tuple[bool, bool, bool, bool, bool, bool]
+            return s.isupper(), s.islower(), s.isdigit(), s.isspace(), \
+                s.isalnum(), s.isalpha()
+
+        def test_str_to(s):
+            # type: (str) -> Tuple[str, str]
+            return s.upper(), s.lower()
+
+        inputs = ["", "12a", "!B", "12", "a", "B", "aB", "$12", "B12", "AB ",
+                  "  \t", "  \n", "\na", "abc"]
+
+        for input in inputs:
+            self.checkScript(test_str_is, (input,))
+            self.checkScript(test_str_to, (input,))
+
+        def test_str_cmp(a, b):
             # type: (str, str) -> Tuple[bool, bool, bool, bool, bool, bool]
             return a != b, a == b, a < b, a > b, a <= b, a >= b
 
-        self.checkScript(test, ("1", "2"))
-        self.checkScript(test, ("2", "1"))
-        self.checkScript(test, ("1", "1"))
+        for i in range(len(inputs) - 1):
+            self.checkScript(test_str_cmp, (inputs[i], inputs[i + 1]))
 
     def test_ord(self):
         def fn(x):

torch/csrc/jit/register_prim_ops.cpp

@@ -1913,6 +1913,68 @@ RegisterOperators reg2({
     Operator(
         "aten::slice(str string, int start, int end=9223372036854775807, int step=1) -> str",
         stringSlice),
+
+// python string is methods return false if empty
+#define DEFINE_STRING_IS_OP(op_name, char_op)                      \
+  Operator(#op_name "(str self) -> bool", [](Stack& stack) {       \
+    auto string = pop(stack).toStringRef();                        \
+    push(                                                          \
+        stack,                                                     \
+        string.size() != 0 &&                                      \
+            std::all_of(string.begin(), string.end(), [](char c) { \
+              return char_op(c);                                   \
+            }));                                                   \
+    return 0;                                                      \
+  })
+
+    // upper and lower require there to be at least one alpha character,
+    // and ignore all other characters
+    Operator(
+        "aten::isupper(str self) -> bool",
+        [](Stack& stack) {
+          auto string = pop(stack).toStringRef();
+          bool found_alpha = false;
+          bool is_upper = true;
+          for (char c : string) {
+            found_alpha |= std::isalpha(c);
+            is_upper &= (!std::isalpha(c) || std::isupper(c));
+          }
+          push(stack, found_alpha && is_upper);
+          return 0;
+        }),
+    Operator(
+        "aten::islower(str self) -> bool",
+        [](Stack& stack) {
+          auto string = pop(stack).toStringRef();
+          bool found_alpha = false;
+          bool is_lower = true;
+          for (char c : string) {
+            found_alpha |= std::isalpha(c);
+            is_lower &= (!std::isalpha(c) || std::islower(c));
+          }
+          push(stack, found_alpha && is_lower);
+          return 0;
+        }),
+
+    DEFINE_STRING_IS_OP(aten::isdigit, std::isdigit),
+    DEFINE_STRING_IS_OP(aten::isspace, std::isspace),
+    DEFINE_STRING_IS_OP(aten::isalnum, std::isalnum),
+    DEFINE_STRING_IS_OP(aten::isalpha, std::isalpha),
+
+#define DEFINE_STRING_CHAR_MAP_OP(op_name, char_op)         \
+  Operator(#op_name "(str self) -> str", [](Stack& stack) { \
+    auto string = pop(stack).toStringRef();                 \
+    std::stringstream ss;                                   \
+    for (char c : string) {                                 \
+      ss << static_cast<char>(char_op(c));                  \
+    }                                                       \
+    push(stack, ss.str());                                  \
+    return 0;                                               \
+  })
+
+    DEFINE_STRING_CHAR_MAP_OP(aten::upper, std::toupper),
+    DEFINE_STRING_CHAR_MAP_OP(aten::lower, std::tolower),
+
     Operator(
         "prim::StringIndex(str string, int index) -> str",
         [](Stack& stack) {