[ENH] add basic filename, path and derivatives JSON creation

[Remi-Gau]

Starts addressing #47 and #79

Nothing crazy.

Reuses the output structure of parse_filename as inputs to make it easier to pass it around.

    %% Create filename
    p.suffix = 'bold';
    p.ext = '.nii';
    p.entities = struct(...
                        'sub', '01', ...
                        'ses', 'test', ...
                        'task', 'face recognition', ...
                        'run', '02');
    
    filename = bids.util.create_filename(p);
    
    assertEqual(filename, 'sub-01_ses-test_task-faceRecognition_run-02_bold.nii');
    
    %% Modify existing filename
    p.entities = struct(...
        'sub', '02', ...
        'task', 'new task');
    
    filename = bids.util.create_filename(p, fullfile(pwd,filename));
    
    assertEqual(filename, 'sub-02_ses-test_task-newTask_run-02_bold.nii');    

    %% Remove entity from filename
    p.entities = struct('ses', '');

    filename = bids.util.create_filename(p, filename);
    
    assertEqual(filename, 'sub-02_task-newTask_run-02_bold.nii');

Could be added:

• a way to "sort" the entities to create the filename. When none is provided, it would rely on the BIDS schema for valid suffix + entities. When we are dealing with non bids valid suffixes, thenwe default to the way they are entered in the structure.
• a way to make camel case optional
• a way to help with path construction for a given file
• add an option to make sure the file follows the bids schema
• for derivatives (with desc entity), return the name and dummy content of associated json fille

[codecov]

Codecov Report

Merging #203 (1435c73) into dev (f7ea16c) will not change coverage.
The diff coverage is 0.00%.

@@          Coverage Diff           @@
##             dev    #203    +/-   ##
======================================
  Coverage   0.00%   0.00%            
======================================
  Files         29      37     +8     
  Lines       1060    1221   +161     
======================================
- Misses      1060    1221   +161     

Flag	Coverage Δ
unittests	0.00% <0.00%> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
+bids/+internal/append_to_layout.m	0.00% <0.00%> (ø)
+bids/+internal/camel_case.m	0.00% <0.00%> (ø)
+bids/+internal/parse_filename.m	0.00% <0.00%> (ø)
+bids/+schema/find_suffix_datatypes.m	0.00% <0.00%> (ø)
+bids/+schema/find_suffix_group.m	0.00% <0.00%> (ø)
+bids/+schema/return_entities_for_suffix.m	0.00% <0.00%> (ø)
+bids/create_filename.m	0.00% <0.00%> (ø)
+bids/create_path.m	0.00% <0.00%> (ø)
+bids/derivatives_json.m	0.00% <0.00%> (ø)
+bids/copy_to_derivative.m	0.00% <0.00%> (ø)
... and 8 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update f7ea16c...1435c73. Read the comment docs.