[mypyc] Use mypy.FORMAT_RE and ConversionSpecifier for % interpolation (

#10877)

mypy.checkstrformat offers regex and ConversionSpecifier for tokenizer, thus 
this PR:

* deletes the redundant code
* uses ConversionSpecifier as FormatOp

mypy/checkstrformat.py

@@ -13,7 +13,7 @@
 import re
 
 from typing import (
-    cast, List, Tuple, Dict, Callable, Union, Optional, Pattern, Match, Set, Any
+    cast, List, Tuple, Dict, Callable, Union, Optional, Pattern, Match, Set
 )
 from typing_extensions import Final, TYPE_CHECKING
 
@@ -50,14 +50,14 @@ def compile_format_re() -> Pattern[str]:
     See https://docs.python.org/3/library/stdtypes.html#printf-style-string-formatting
     The regexp is intentionally a bit wider to report better errors.
     """
-    key_re = r'(\(([^()]*)\))?'  # (optional) parenthesised sequence of characters.
-    flags_re = r'([#0\-+ ]*)'  # (optional) sequence of flags.
-    width_re = r'(\*|[1-9][0-9]*)?'  # (optional) minimum field width (* or numbers).
-    precision_re = r'(?:\.(\*|[0-9]+)?)?'  # (optional) . followed by * of numbers.
+    key_re = r'(\((?P<key>[^)]*)\))?'  # (optional) parenthesised sequence of characters.
+    flags_re = r'(?P<flag>[#0\-+ ]*)'  # (optional) sequence of flags.
+    width_re = r'(?P<width>[1-9][0-9]*|\*)?'  # (optional) minimum field width (* or numbers).
+    precision_re = r'(?:\.(?P<precision>\*|[0-9]+)?)?'  # (optional) . followed by * of numbers.
     length_mod_re = r'[hlL]?'  # (optional) length modifier (unused).
-    type_re = r'(.)?'  # conversion type.
+    type_re = r'(?P<type>.)?'  # conversion type.
     format_re = '%' + key_re + flags_re + width_re + precision_re + length_mod_re + type_re
-    return re.compile(format_re)
+    return re.compile('({})'.format(format_re))
 
 
 def compile_new_format_re(custom_spec: bool) -> Pattern[str]:
@@ -114,16 +114,20 @@ def compile_new_format_re(custom_spec: bool) -> Pattern[str]:
 
 
 class ConversionSpecifier:
-    def __init__(self, key: Optional[str],
-                 flags: str, width: str, precision: str, type: str,
+    def __init__(self, type: str,
+                 key: Optional[str],
+                 flags: Optional[str],
+                 width: Optional[str],
+                 precision: Optional[str],
                  format_spec: Optional[str] = None,
                  conversion: Optional[str] = None,
-                 field: Optional[str] = None) -> None:
+                 field: Optional[str] = None,
+                 whole_seq: Optional[str] = None) -> None:
+        self.type = type
         self.key = key
         self.flags = flags
         self.width = width
         self.precision = precision
-        self.type = type
         # Used only for str.format() calls (it may be custom for types with __format__()).
         self.format_spec = format_spec
         self.non_standard_format_spec = False
@@ -132,24 +136,27 @@ def __init__(self, key: Optional[str],
         # Full formatted expression (i.e. key plus following attributes and/or indexes).
         # Used only for str.format() calls.
         self.field = field
+        self.whole_seq = whole_seq
 
     @classmethod
-    def from_match(cls, match_obj: Match[str],
+    def from_match(cls, match: Match[str],
                    non_standard_spec: bool = False) -> 'ConversionSpecifier':
         """Construct specifier from match object resulted from parsing str.format() call."""
-        match = cast(Any, match_obj)  # TODO: remove this once typeshed is fixed.
         if non_standard_spec:
-            spec = cls(match.group('key'),
-                       flags='', width='', precision='', type='',
+            spec = cls(type='',
+                       key=match.group('key'),
+                       flags='', width='', precision='',
                        format_spec=match.group('format_spec'),
                        conversion=match.group('conversion'),
                        field=match.group('field'))
             spec.non_standard_format_spec = True
             return spec
         # Replace unmatched optional groups with empty matches (for convenience).
-        return cls(match.group('key'),
-                   flags=match.group('flags') or '', width=match.group('width') or '',
-                   precision=match.group('precision') or '', type=match.group('type') or '',
+        return cls(type=match.group('type') or '',
+                   key=match.group('key'),
+                   flags=match.group('flags') or '',
+                   width=match.group('width') or '',
+                   precision=match.group('precision') or '',
                    format_spec=match.group('format_spec'),
                    conversion=match.group('conversion'),
                    field=match.group('field'))
@@ -622,10 +629,12 @@ def check_str_interpolation(self,
 
     def parse_conversion_specifiers(self, format: str) -> List[ConversionSpecifier]:
         specifiers: List[ConversionSpecifier] = []
-        for parens_key, key, flags, width, precision, type in FORMAT_RE.findall(format):
+        for whole_seq, parens_key, key, flags, width, precision, type \
+                in FORMAT_RE.findall(format):
             if parens_key == '':
                 key = None
-            specifiers.append(ConversionSpecifier(key, flags, width, precision, type))
+            specifiers.append(ConversionSpecifier(type, key, flags, width, precision,
+                                                  whole_seq=whole_seq))
         return specifiers
 
     def analyze_conversion_specifiers(self, specifiers: List[ConversionSpecifier],

mypyc/irbuild/expression.py

@@ -569,7 +569,8 @@ def transform_basic_comparison(builder: IRBuilder,
 def translate_str_format_percent_sign(builder: IRBuilder,
                                       format_expr: StrExpr,
                                       rhs: Expression) -> Value:
-    literals, conversion_types = tokenizer_printf_style(format_expr.value)
+    literals, conversion_specifiers = tokenizer_printf_style(format_expr.value)
+
     variables = []
     if isinstance(rhs, TupleExpr):
         raw_variables = rhs.items
@@ -578,15 +579,16 @@ def translate_str_format_percent_sign(builder: IRBuilder,
     else:
         raw_variables = []
 
-    is_conversion_matched = (len(conversion_types) == len(raw_variables))
+    is_conversion_matched = (len(conversion_specifiers) == len(raw_variables))
 
     if is_conversion_matched:
-        for typ, var in zip(conversion_types, raw_variables):
+        for specifier, var in zip(conversion_specifiers, raw_variables):
             node_type = builder.node_type(var)
-            if typ == '%d' and (is_int_rprimitive(node_type)
-                                or is_short_int_rprimitive(node_type)):
+            format_type = specifier.whole_seq
+            if format_type == '%d' and (is_int_rprimitive(node_type)
+                                        or is_short_int_rprimitive(node_type)):
                 var_str = builder.call_c(int_to_str_op, [builder.accept(var)], format_expr.line)
-            elif typ == '%s':
+            elif format_type == '%s':
                 if is_str_rprimitive(node_type):
                     var_str = builder.accept(var)
                 else:

mypyc/irbuild/format_str_tokenizer.py

@@ -3,46 +3,37 @@
 import re
 from typing import List, Tuple
 
+from mypy.checkstrformat import (
+    FORMAT_RE, ConversionSpecifier
+)
 from mypyc.ir.ops import Value, Integer
 from mypyc.ir.rtypes import c_pyssize_t_rprimitive
 from mypyc.irbuild.builder import IRBuilder
 from mypyc.primitives.str_ops import str_build_op
 
-# printf-style String Formatting:
-# https://docs.python.org/3/library/stdtypes.html#old-string-formatting
-printf_style_pattern = re.compile(r"""
-    (
-    %                                # Start sign
-    (?:\((?P<key>[^)]*)\))?          # Optional: Mapping key
-    (?P<flag>[-+#0 ]+)?              # Optional: Conversion flags
-    (?P<width>\d+|\*)?               # Optional: Minimum field width
-    (?:\.(?P<precision>\d+|\*))?     # Optional: Precision
-    [hlL]?                           # Optional: Length modifier, Ignored
-    (?P<type>[diouxXeEfFgGcrsa])     # Conversion type
-    | %%)
-    """, re.VERBOSE)
 
-
-def tokenizer_printf_style(format_str: str) -> Tuple[List[str], List[str]]:
+def tokenizer_printf_style(format_str: str) -> Tuple[List[str], List[ConversionSpecifier]]:
     """Tokenize a printf-style format string using regex.
 
     Return:
         A list of string literals and a list of conversion operations
     """
-    literals = []
-    format_ops = []
+    literals: List[str] = []
+    specifiers: List[ConversionSpecifier] = []
     last_end = 0
 
-    for m in re.finditer(printf_style_pattern, format_str):
+    for m in re.finditer(FORMAT_RE, format_str):
+        whole_seq, parens_key, key, flags, width, precision, conversion_type = m.groups()
+        specifiers.append(ConversionSpecifier(conversion_type, key, flags, width, precision,
+                                              whole_seq=whole_seq))
+
         cur_start = m.start(1)
-        format_tmp = m.group(1)
         literals.append(format_str[last_end:cur_start])
-        format_ops.append(format_tmp)
-        last_end = cur_start + len(format_tmp)
+        last_end = cur_start + len(whole_seq)
 
     literals.append(format_str[last_end:])
 
-    return literals, format_ops
+    return literals, specifiers
 
 
 def join_formatted_strings(builder: IRBuilder, literals: List[str],

mypyc/test/test_stringformatting.py

@@ -1,16 +1,31 @@
 import unittest
+from typing import List
 
 from mypyc.irbuild.format_str_tokenizer import tokenizer_printf_style
 
 
 class TestStringFormatting(unittest.TestCase):
+
     def test_tokenizer_printf_style(self) -> None:
-        assert tokenizer_printf_style("I'm %s, id years old") == \
-               (["I'm ", ', id years old'], ['%s'])
-        assert tokenizer_printf_style("Test: %i%%, Test: %02d, Test: %.2f") == \
-               (['Test: ', '', ', Test: ', ', Test: ', ''], ['%i', '%%', '%02d', '%.2f'])
-        assert tokenizer_printf_style("ioasdfyuia%i%%%20s%d%sdafafadfa%s%d%x%E%.2f") == \
-               (['ioasdfyuia', '', '', '', '', 'dafafadfa', '', '', '', '', ''],
-                ['%i', '%%', '%20s', '%d', '%s', '%s', '%d', '%x', '%E', '%.2f'])
-        assert tokenizer_printf_style("Special: %#20.2f%d, test: ") == \
-               (['Special: ', '', ', test: '], ['%#20.2f', '%d'])
+
+        def tokenizer_printf_style_helper(format_str: str,
+                                          literals: List[str], conversion: List[str]) -> bool:
+            l, specs = tokenizer_printf_style(format_str)
+            return literals == l and conversion == [x.whole_seq for x in specs]
+
+        assert tokenizer_printf_style_helper(
+            "I'm %s, id years old",
+            ["I'm ", ', id years old'],
+            ['%s'])
+        assert tokenizer_printf_style_helper(
+            "Test: %i%%, Test: %02d, Test: %.2f",
+            ['Test: ', '', ', Test: ', ', Test: ', ''],
+            ['%i', '%%', '%02d', '%.2f'])
+        assert tokenizer_printf_style_helper(
+            "ioasdfyuia%i%%%20s%d%sdafafadfa%s%d%x%E%.2f",
+            ['ioasdfyuia', '', '', '', '', 'dafafadfa', '', '', '', '', ''],
+            ['%i', '%%', '%20s', '%d', '%s', '%s', '%d', '%x', '%E', '%.2f'])
+        assert tokenizer_printf_style_helper(
+            "Special: %#20.2f%d, test: ",
+            ['Special: ', '', ', test: '],
+            ['%#20.2f', '%d'])