make_macros for python3

script/make_macros_py3.py

@@ -0,0 +1,158 @@
+#! /usr/bin/env python
+
+# This file is based on script/make_macros.py and updated for Python3.
+
+# This file is part of Better Enums, released under the BSD 2-clause license.
+# See LICENSE for details, or visit http://github.com/aantron/better-enums.
+
+# You only need this script if you are developing enum.h, or run into a limit.
+#
+# This script generates the macros BETTER_ENUMS_PP_MAP and BETTER_ENUMS_ITERATE,
+# used internally by enum.h. These are already inlined into enum.h.
+#
+# BETTER_ENUMS_PP_MAP has a limit, which determines the maximum number of
+# constants an enum can have. By default, this limit is 64 constants.
+#
+# BETTER_ENUMS_ITERATE also has a limit. This one determines the maximum length
+# of the name of a constant that is followed by an initializer (" = 2") when
+# compiling an enum with constexpr _to_string function (i.e. usually, this limit
+# does not apply). By default, the limit is 23 characters (24 with the
+# obligatory null terminator).
+#
+# If either of these limits is inadequate, you can still compile your code
+# without changing enum.h. You need to generate an external macro file with
+# definitions of these macros with relaxed limits, and tell enum.h to use the
+# external macro file. Here is how this is done, supposing you want support for
+# 512 constants of length up to 127 (128 with null terminator):
+#
+# 0. MACRO_FILE is the name of the external macro file. Make sure you put it
+#    somewhere in your include path.
+# 1. Run python make_macros.py 512 128 > MACRO_FILE
+# 2. Build your code with an additional compiler flag:
+#    - for gcc and clang, -DBETTER_ENUMS_MACRO_FILE='<MACRO_FILE>'
+#    - for VC++, /DBETTER_ENUMS_MACRO_FILE='<MACRO_FILE>'
+#    or use any other method of getting these macros defined.
+# 3. Compile your code. Your macro file should be included, and enum.h should
+#    happily work with whatever limits you chose.
+
+import os
+import sys
+
+class MultiLine(object):
+    def __init__(self, stream, indent = 4, columns = 80, initial_column = 0):
+        self._columns_left = columns - initial_column
+        self._indent = indent
+        self._columns = columns
+        self._stream = stream
+
+    def write(self, token, last = False):
+        break_line = False
+        if last:
+            if len(token) > self._columns_left:
+                break_line = True
+        else:
+            if len(token) > self._columns_left - 1:
+                break_line = True
+
+        if break_line:
+            print(' ' * (self._columns_left - 1) + '\\', file=self._stream)
+            self._stream.write(' ' * self._indent)
+            self._columns_left = self._columns - self._indent
+            token = token.lstrip()
+
+        self._stream.write(token)
+        self._columns_left -= len(token)
+
+def fprint(stream, *args):
+    fline = " ".join(map(str, args))
+    stream.write(fline + "\n")
+
+def generate(stream, constants, length, script):
+    fprint(stream, '// This file was automatically generated by ' + script)
+
+    fprint(stream, '')
+    fprint(stream, '#pragma once')
+    fprint(stream, '')
+    fprint(stream, '#ifndef BETTER_ENUMS_MACRO_FILE_H')
+    fprint(stream, '#define BETTER_ENUMS_MACRO_FILE_H')
+
+    fprint(stream, '')
+    fprint(stream, '#define BETTER_ENUMS_PP_MAP(macro, data, ...) \\')
+    fprint(stream, '    BETTER_ENUMS_ID( \\')
+    fprint(stream, '        BETTER_ENUMS_APPLY( \\')
+    fprint(stream, '            BETTER_ENUMS_PP_MAP_VAR_COUNT, \\')
+    fprint(stream, '            BETTER_ENUMS_PP_COUNT(__VA_ARGS__)) \\')
+    fprint(stream, '        (macro, data, __VA_ARGS__))')
+
+    fprint(stream, '')
+    fprint(stream, '#define BETTER_ENUMS_PP_MAP_VAR_COUNT(count) ' + \
+                     'BETTER_ENUMS_M ## count')
+
+    fprint(stream, '')
+    fprint(stream, '#define BETTER_ENUMS_APPLY(macro, ...) ' + \
+                      'BETTER_ENUMS_ID(macro(__VA_ARGS__))')
+
+    fprint(stream, '')
+    fprint(stream, '#define BETTER_ENUMS_ID(x) x')
+
+    fprint(stream, '')
+    fprint(stream, '#define BETTER_ENUMS_M1(m, d, x) m(d,0,x)')
+    for index in range(2, constants + 1):
+        fprint(stream, '#define BETTER_ENUMS_M' + str(index) + \
+                         '(m,d,x,...) m(d,' + str(index - 1) + ',x) \\')
+        fprint(stream, '    BETTER_ENUMS_ID(BETTER_ENUMS_M' + \
+                         str(index - 1) + '(m,d,__VA_ARGS__))')
+
+    fprint(stream, '')
+    pp_count_impl_prefix = '#define BETTER_ENUMS_PP_COUNT_IMPL(_1,'
+    stream.write(pp_count_impl_prefix)
+    pp_count_impl = MultiLine(stream = stream, indent = 4,
+                              initial_column = len(pp_count_impl_prefix))
+    for index in range(2, constants + 1):
+        pp_count_impl.write(' _' + str(index) + ',')
+    pp_count_impl.write(' count,')
+    pp_count_impl.write(' ...)')
+    pp_count_impl.write(' count', last = True)
+    fprint(stream, '')
+
+    fprint(stream, '')
+    fprint(stream, '#define BETTER_ENUMS_PP_COUNT(...) \\')
+    pp_count_prefix = \
+        '    BETTER_ENUMS_ID(BETTER_ENUMS_PP_COUNT_IMPL(__VA_ARGS__,'
+    stream.write(pp_count_prefix)
+    pp_count = MultiLine(stream = stream, indent = 8,
+                         initial_column = len(pp_count_prefix))
+    for index in range(0, constants - 1):
+        pp_count.write(' ' + str(constants - index) + ',')
+    pp_count.write(' 1))', last = True)
+    fprint(stream, '')
+
+    fprint(stream, '')
+    iterate_prefix = '#define BETTER_ENUMS_ITERATE(X, f, l)'
+    stream.write(iterate_prefix)
+    iterate = MultiLine(stream = stream, indent = 4,
+                        initial_column = len(iterate_prefix))
+    for index in range(0, length):
+        iterate.write(' X(f, l, %i)' % index)
+    fprint(stream, '')
+
+    fprint(stream, '')
+    fprint(stream, '#endif // #ifndef BETTER_ENUMS_MACRO_FILE_H')
+
+def print_err(*args):
+    err_msg= " ".join(str(arg) for arg in args)
+    sys.stderr.write(err_msg + "\n")
+
+if __name__ == '__main__':
+    if len(sys.argv) != 3:
+        print_err('Usage: ' + sys.argv[0] + ' CONSTANTS LENGTH > FILE')
+        print_err("")
+        print_err("Prints map macro definition to FILE.")
+        print_err("CONSTANTS is the number of constants to support.")
+        print_err("LENGTH is the maximum length of a constant name.")
+        sys.exit(1)
+
+    generate(sys.stdout, int(sys.argv[1]), int(sys.argv[2]),
+             os.path.basename(sys.argv[0]))
+
+    sys.exit(0)