Replace all %-substitution and .format() calls with f-strings (#506)

Eliminate all old-style string replacement (`%` substitutions) and
explicit `.format()` calls, in favor of equivalent f-strings.

Author: kleisauke

doc/intro.rst

@@ -333,11 +333,11 @@ Handlers are given a `progress` object containing a number of useful fields.
 For example::
 
    def eval_handler(image, progress):
-       print('run time so far (secs) = {}'.format(progress.run))
-       print('estimated time of arrival (secs) = {}'.format(progress.eta))
-       print('total number of pels to process = {}'.format(progress.tpels))
-       print('number of pels processed so far = {}'.format(progress.npels))
-       print('percent complete = {}'.format(progress.percent))
+       print(f'   run = {progress.run} (seconds of run time)')
+       print(f'   eta = {progress.eta} (estimated seconds left)')
+       print(f'   tpels = {progress.tpels} (total number of pels)')
+       print(f'   npels = {progress.npels} (number of pels computed so far)')
+       print(f'   percent = {progress.percent} (percent complete)')
 
 Use :meth:`.Image.set_kill` on the image to stop computation early. 
 

examples/pil-numpy-pyvips.py

@@ -8,7 +8,7 @@
 import numpy as np
 
 if len(sys.argv) != 3:
-    print('usage: {0} input-filename output-filename'.format(sys.argv[0]))
+    print(f'usage: {sys.argv[0]} input-filename output-filename')
     sys.exit(-1)
 
 

examples/progress.py

@@ -4,7 +4,7 @@
 
 
 def progress_print(name, progress):
-    print(f'signal {name}:'.format(name))
+    print(f'signal {name}:')
     print(f'   run = {progress.run} (seconds of run time)')
     print(f'   eta = {progress.eta} (estimated seconds left)')
     print(f'   tpels = {progress.tpels} (total number of pels)')

examples/soak-test.py

@@ -7,7 +7,7 @@
 pyvips.cache_set_max(0)
 
 for i in range(1000):
-    print("loop {0} ...".format(i))
+    print(f"loop {i} ...")
     im = pyvips.Image.new_from_file(sys.argv[1])
     im = im.embed(100, 100, 3000, 3000, extend="mirror")
     im.write_to_file("x.v")

examples/try5.py

@@ -11,7 +11,7 @@
 
 def should_equal(test, a, b):
     if abs(a - b) > 0.01:
-        print('%s: seen %g and %g' % (test, a, b))
+        print(f'{test}: seen {a:g} and {b:g}')
         sys.exit(1)
 
 

pyvips/__init__.py

@@ -32,17 +32,16 @@
     lib_minor = vips_lib.vips_version(1)
     wrap_major = vips_lib.VIPS_MAJOR_VERSION
     wrap_minor = vips_lib.VIPS_MINOR_VERSION
-    logger.debug('Module generated for libvips %s.%s' %
-                 (wrap_major, wrap_minor))
-    logger.debug('Linked to libvips %s.%s' % (lib_major, lib_minor))
+    logger.debug(f'Module generated for libvips {wrap_major}.{wrap_minor}')
+    logger.debug(f'Linked to libvips {lib_major}.{lib_minor}')
 
     if wrap_major != lib_major or wrap_minor != lib_minor:
         raise Exception('bad wrapper version')
 
     API_mode = True
 
 except Exception as e:
-    logger.debug('Binary module load failed: %s' % e)
+    logger.debug(f'Binary module load failed: {e}')
     logger.debug('Falling back to ABI mode')
 
     from cffi import FFI
@@ -141,14 +140,14 @@ class GLogLevelFlags(object):
     @ffi.def_extern()
     def _log_handler_callback(domain, level, message, user_data):
         logger.log(GLogLevelFlags.LEVEL_TO_LOGGER[level],
-                   '{0}: {1}'.format(_to_string(domain), _to_string(message)))
+                   f'{_to_string(domain)}: {_to_string(message)}')
 
     # keep a ref to the cb to stop it being GCd
     _log_handler_cb = glib_lib._log_handler_callback
 else:
     def _log_handler_callback(domain, level, message, user_data):
         logger.log(GLogLevelFlags.LEVEL_TO_LOGGER[level],
-                   '{0}: {1}'.format(_to_string(domain), _to_string(message)))
+                   f'{_to_string(domain)}: {_to_string(message)}')
 
     # keep a ref to the cb to stop it being GCd
     _log_handler_cb = ffi.callback('GLogFunc', _log_handler_callback)

pyvips/error.py

@@ -68,7 +68,7 @@ def __init__(self, message, detail=None):
         logger.debug('Error %s %s', self.message, self.detail)
 
     def __str__(self):
-        return '{0}\n  {1}'.format(self.message, self.detail)
+        return f'{self.message}\n  {self.detail}'
 
 
 __all__ = [

pyvips/gobject.py

@@ -159,7 +159,7 @@ def new_pointer_from_gtype(gtype):
 
         pointer = gobject_lib.g_object_new(gtype, ffi.NULL)
         if pointer == ffi.NULL:
-            raise Error("can't create {0}".format(type_name(gtype)))
+            raise Error(f"can't create {type_name(gtype)}")
 
         return pointer
 
@@ -176,7 +176,7 @@ def signal_connect(self, name, callback):
         """
 
         if name not in _marshalers:
-            raise Error('unsupported signal "{0}"'.format(name))
+            raise Error(f'unsupported signal "{name}"')
 
         go = ffi.cast('GObject *', self.pointer)
         handle = ffi.new_handle(callback)

pyvips/gvalue.py

@@ -84,7 +84,7 @@ def gtype_to_python(gtype):
             name = type_name(gtype)
             if name.startswith('Vips'):
                 name = name[4:]
-            return "Union[str, %s]" % name
+            return f"Union[str, {name}]"
         if gtype in GValue._gtype_to_python:
             return GValue._gtype_to_python[gtype]
         if fundamental in GValue._gtype_to_python:

pyvips/pyvips_build.py

@@ -32,9 +32,10 @@
 ''' if major == 8 and minor < 6 else ''
 
 ffibuilder.set_source("_libvips",
-    r"""
+    f"""
         #include <vips/vips.h>
-    """ + compat,
+        {compat}
+    """,
     **pkgconfig.parse('vips'))
 
 features = {