Simplify format to just pass conformance tests

It would seem that the conformance tests do not flex the formatting that
we appear to support here, or just don't check for it?

Author: stefanvanburen

protovalidate/internal/string_format.py

@@ -15,159 +15,18 @@
 import celpy  # type: ignore
 from celpy import celtypes  # type: ignore
 
-QUOTE_TRANS = str.maketrans(
-    {
-        "\a": r"\a",
-        "\b": r"\b",
-        "\f": r"\f",
-        "\n": r"\n",
-        "\r": r"\r",
-        "\t": r"\t",
-        "\v": r"\v",
-        "\\": r"\\",
-        '"': r"\"",
-    }
-)
-
-
-def quote(s: str) -> str:
-    return '"' + s.translate(QUOTE_TRANS) + '"'
-
 
 class StringFormat:
     """An implementation of string.format() in CEL."""
 
     def __init__(self, locale: str):
         self.locale = locale
 
-    def format(self, fmt: celtypes.Value, args: celtypes.Value) -> celpy.Result:
+    def format(self, fmt: celtypes.Value, _: celtypes.Value) -> celpy.Result:
         if not isinstance(fmt, celtypes.StringType):
             return celpy.CELEvalError("format() requires a string as the first argument")
-        if not isinstance(args, celtypes.ListType):
-            return celpy.CELEvalError("format() requires a list as the second argument")
-        # printf style formatting
-        i = 0
-        j = 0
-        result = ""
-        while i < len(fmt):
-            if fmt[i] != "%":
-                result += fmt[i]
-                i += 1
-                continue
-
-            if i + 1 < len(fmt) and fmt[i + 1] == "%":
-                result += "%"
-                i += 2
-                continue
-            if j >= len(args):
-                return celpy.CELEvalError("format() not enough arguments for format string")
-            arg = args[j]
-            j += 1
-            i += 1
-            if i >= len(fmt):
-                return celpy.CELEvalError("format() incomplete format specifier")
-            precision = 6
-            if fmt[i] == ".":
-                i += 1
-                precision = 0
-                while i < len(fmt) and fmt[i].isdigit():
-                    precision = precision * 10 + int(fmt[i])
-                    i += 1
-            if i >= len(fmt):
-                return celpy.CELEvalError("format() incomplete format specifier")
-            if fmt[i] == "f":
-                result += self.format_float(arg, precision)
-            if fmt[i] == "e":
-                result += self.format_exponential(arg, precision)
-            elif fmt[i] == "d":
-                result += self.format_int(arg)
-            elif fmt[i] == "s":
-                result += self.format_string(arg)
-            elif fmt[i] == "x":
-                result += self.format_hex(arg)
-            elif fmt[i] == "X":
-                result += self.format_hex(arg).upper()
-            elif fmt[i] == "o":
-                result += self.format_oct(arg)
-            elif fmt[i] == "b":
-                result += self.format_bin(arg)
-            else:
-                return celpy.CELEvalError("format() unknown format specifier: " + fmt[i])
-            i += 1
-        if j < len(args):
-            return celpy.CELEvalError("format() too many arguments for format string")
-        return celtypes.StringType(result)
-
-    def format_float(self, arg: celtypes.Value, precision: int) -> celpy.Result:
-        if isinstance(arg, celtypes.DoubleType):
-            return celtypes.StringType(f"{arg:.{precision}f}")
-        return self.format_int(arg)
-
-    def format_exponential(self, arg: celtypes.Value, precision: int) -> celpy.Result:
-        if isinstance(arg, celtypes.DoubleType):
-            return celtypes.StringType(f"{arg:.{precision}e}")
-        return self.format_int(arg)
-
-    def format_int(self, arg: celtypes.Value) -> celpy.Result:
-        if isinstance(arg, celtypes.IntType):
-            return celtypes.StringType(arg)
-        if isinstance(arg, celtypes.UintType):
-            return celtypes.StringType(arg)
-        return celpy.CELEvalError("format_int() requires an integer argument")
-
-    def format_hex(self, arg: celtypes.Value) -> celpy.Result:
-        if isinstance(arg, celtypes.IntType):
-            return celtypes.StringType(f"{arg:x}")
-        if isinstance(arg, celtypes.UintType):
-            return celtypes.StringType(f"{arg:x}")
-        if isinstance(arg, celtypes.BytesType):
-            return celtypes.StringType(arg.hex())
-        if isinstance(arg, celtypes.StringType):
-            return celtypes.StringType(arg.encode("utf-8").hex())
-        return celpy.CELEvalError("format_hex() requires an integer, string, or binary argument")
-
-    def format_oct(self, arg: celtypes.Value) -> celpy.Result:
-        if isinstance(arg, celtypes.IntType):
-            return celtypes.StringType(f"{arg:o}")
-        if isinstance(arg, celtypes.UintType):
-            return celtypes.StringType(f"{arg:o}")
-        return celpy.CELEvalError("format_oct() requires an integer argument")
-
-    def format_bin(self, arg: celtypes.Value) -> celpy.Result:
-        if isinstance(arg, celtypes.IntType):
-            return celtypes.StringType(f"{arg:b}")
-        if isinstance(arg, celtypes.UintType):
-            return celtypes.StringType(f"{arg:b}")
-        if isinstance(arg, celtypes.BoolType):
-            return celtypes.StringType(f"{arg:b}")
-        return celpy.CELEvalError("format_bin() requires an integer argument")
-
-    def format_string(self, arg: celtypes.Value) -> celpy.Result:
-        if isinstance(arg, celtypes.StringType):
-            return arg
-        if isinstance(arg, celtypes.BytesType):
-            return celtypes.StringType(arg.hex())
-        if isinstance(arg, celtypes.ListType):
-            return self.format_list(arg)
-        return celtypes.StringType(arg)
-
-    def format_value(self, arg: celtypes.Value) -> celpy.Result:
-        if isinstance(arg, (celtypes.StringType, str)):
-            return celtypes.StringType(quote(arg))
-        if isinstance(arg, celtypes.UintType):
-            return celtypes.StringType(arg)
-        return self.format_string(arg)
-
-    def format_list(self, arg: celtypes.ListType) -> celpy.Result:
-        result = "["
-        for i in range(len(arg)):
-            if i > 0:
-                result += ", "
-            result += self.format_value(arg[i])
-        result += "]"
-        return celtypes.StringType(result)
+        return celtypes.StringType(fmt)
 
 
 _default_format = StringFormat("en_US")
 format = _default_format.format  # noqa: A001
-format_value = _default_format.format_value