RF: refactor PARREC file meths for keyword only

Use and test keyword-onliness of permit_truncated, scaling argument to
PARRECImage file loading methods.

Author: matthew-brett

bin/parrec2nii

@@ -138,7 +138,9 @@ def proc_file(infile, opts):
     # load the PAR header and data
     scaling = None if opts.scaling == 'off' else opts.scaling
     infile = fname_ext_ul_case(infile)
-    pr_img = pr.load(infile, opts.permit_truncated, scaling)
+    pr_img = pr.load(infile,
+                     permit_truncated=opts.permit_truncated,
+                     scaling=scaling)
     pr_hdr = pr_img.header
     raw_data = pr_img.dataobj.get_unscaled()
     affine = pr_hdr.get_affine(origin=opts.origin)

nibabel/parrec.py

@@ -82,6 +82,7 @@
 from copy import deepcopy
 import re
 
+from .keywordonly import kw_only_meth
 from .spatialimages import SpatialImage, Header
 from .eulerangles import euler2mat
 from .volumeutils import Recoder, array_from_file, BinOpener
@@ -900,6 +901,7 @@ class PARRECImage(SpatialImage):
     ImageArrayProxy = PARRECArrayProxy
 
     @classmethod
+    @kw_only_meth(1)
     def from_file_map(klass, file_map, permit_truncated=False, scaling='dv'):
         pt = permit_truncated
         with file_map['header'].get_prepare_fileobj('rt') as hdr_fobj:
@@ -911,13 +913,14 @@ def from_file_map(klass, file_map, permit_truncated=False, scaling='dv'):
                      file_map=file_map)
 
     @classmethod
+    @kw_only_meth(1)
     def from_filename(klass, filename, permit_truncated=False, scaling='dv'):
         file_map = klass.filespec_to_file_map(filename)
-        return klass.from_file_map(file_map, permit_truncated, scaling)
+        return klass.from_file_map(file_map,
+                                   permit_truncated=permit_truncated,
+                                   scaling=scaling)
 
-    @classmethod
-    def load(klass, filename, permit_truncated=False, scaling='dv'):
-        return klass.from_filename(filename, permit_truncated, scaling)
+    load = from_filename
 
 
 load = PARRECImage.load

nibabel/tests/test_parrec.py

@@ -434,17 +434,25 @@ def test_image_creation():
         (PARRECImage.from_file_map, good_map, trunc_map)):
         img = func(good_param)
         assert_array_equal(img.dataobj, arr_prox_dv)
-        img = func(good_param, False)
+        # permit_truncated is keyword only
+        assert_raises(TypeError, func, good_param, False)
+        img = func(good_param, permit_truncated=False)
         assert_array_equal(img.dataobj, arr_prox_dv)
-        img = func(good_param, False, 'dv')
+        # scaling is keyword only
+        assert_raises(TypeError, func, good_param, False, 'dv')
+        img = func(good_param, permit_truncated=False, scaling='dv')
         assert_array_equal(img.dataobj, arr_prox_dv)
-        img = func(good_param, False, 'fp')
+        img = func(good_param, scaling='dv')
+        assert_array_equal(img.dataobj, arr_prox_dv)
+        # Can use fp scaling
+        img = func(good_param, scaling='fp')
         assert_array_equal(img.dataobj, arr_prox_fp)
+        # Truncated raises error without permit_truncated=True
         assert_raises(PARRECError, func, trunc_param)
-        assert_raises(PARRECError, func, trunc_param, False)
-        img = func(trunc_param, True)
+        assert_raises(PARRECError, func, trunc_param, permit_truncated=False)
+        img = func(trunc_param, permit_truncated=True)
         assert_array_equal(img.dataobj, arr_prox_dv)
-        img = func(trunc_param, True, 'dv')
+        img = func(trunc_param, permit_truncated=True, scaling='dv')
         assert_array_equal(img.dataobj, arr_prox_dv)
-        img = func(trunc_param, True, 'fp')
+        img = func(trunc_param, permit_truncated=True, scaling='fp')
         assert_array_equal(img.dataobj, arr_prox_fp)