generateExtension now takes multiple arguments

To imitate the original generateCore behavior since that has
deprecated its own arguments.

Updated documentation and README to reflect these changes.

README.md

@@ -9,7 +9,7 @@ A Matlab interface for reading and writing Neurodata Without Borders (NWB) 2.0 f
 Download the current release of MatNWB from the [MatNWB releases page](https://github.com/NeurodataWithoutBorders/matnwb/releases) or from the [![View NeurodataWithoutBorders/matnwb on File Exchange](https://www.mathworks.com/matlabcentral/images/matlab-file-exchange.svg)](https://www.mathworks.com/matlabcentral/fileexchange/67741-neurodatawithoutborders-matnwb). You can also check out the latest development version via 
 
 ```bash
-git clone https://github.com/NeurodataWithoutBorders/matnwb.git
+git clone --recurse-submodules https://github.com/NeurodataWithoutBorders/matnwb.git
 ```
 
 ### Step 2: Generate the API
@@ -19,37 +19,32 @@ From the Matlab command line, add MatNWB to the Matlab path and generate the cor
 ```matlab
 cd matnwb
 addpath(genpath(pwd));
-generateCore(); % generate core namespace located in the repository.
+generateCore(); % generate the most recent nwb-schema release.
 ```
 
 ### Optional: Generate MatNWB code for extensions
 
-The `generateCore` command also takes variable arguments from any extensions.
+The `generateExtension` command generates extension classes given a file path to the extension's namespace.
 
 ```matlab
-generateCore('schema/core/nwb.namespace.yaml', '.../my_extensions1.namespace.yaml',...);
-```
-
-You can also generate extensions without generating the core classes in this way:
-
-```matlab
-generateExtension('my_extension.namespace.yaml');
+generateExtension('schema/core/nwb.namespace.yaml', '.../my_extensions1.namespace.yaml',...);
 ```
 
 Generated Matlab code will be put a `+types` subdirectory.  This is a Matlab package.  When the `+types` folder is accessible to the Matlab path, the generated code will be used for reading NWBFiles.
 
 ```matlab
-nwb=nwbRead('data.nwb');
+nwb = nwbRead('data.nwb');
 ```
 
-### Optional: Download the NWB format schema
+### Optional: Generate an older core schema
 
-Download the current release of the NWB format schema from the [nwb-schema releases page](https://github.com/NeurodataWithoutBorders/nwb-schema/releases) or check out the latest development via 
+The `generateCore` command can generate older versions of the nwb schema.
 
-```bash
-git clone --recursive https://github.com/NeurodataWithoutBorders/nwb-schema.git
+```matlab
+generateCore('2.2.1'); % generate schema 2.2.1
 ```
-Then re-run `generateCore()` to update the API from the updated schema.
+
+Currently, only schemas 2.2.x are supported (2.1.0 and 2.0.1 are not supported at this time).
 
 ## Tutorials
 

generateExtension.m

@@ -1,6 +1,6 @@
-function generateExtension(source)
+function generateExtension(varargin)
 % GENERATEEXTENSION Generate Matlab classes from NWB extension schema file
-%   GENERATECORE(extension_path...)  Generate classes
+%   GENERATEEXTENSION(extension_path...)  Generate classes
 %   (Matlab m-files) from one or more NWB:N schema extension namespace
 %   files.  A registry of already generated core types is used to resolve
 %   dependent types.
@@ -13,19 +13,22 @@ function generateExtension(source)
 %   current working directory.
 %
 %   Example:
-%      generateCore('schema\core\nwb.namespace.yaml');
-%      generateExtension('schema\myext\myextension.namespace.yaml')
+%      generateExtension('schema\myext\myextension.namespace.yaml', 'schema\myext2\myext2.namespace.yaml');
 %
 %   See also GENERATECORE
-validateattributes(source, {'char', 'string'}, {'scalartext'});
-
-[localpath, ~, ~] = fileparts(source);
-assert(2 == exist(source, 'file'),...
-    'MATNWB:FILE', 'Path to file `%s` could not be found.', source);
-fid = fopen(source);
-namespaceText = fread(fid, '*char') .';
-fclose(fid);
-
-Namespace = spec.generate(namespaceText, localpath);
-file.writeNamespace(Namespace.name);
+for i = 1:length(varargin)
+    source = varargin{i};
+    validateattributes(source, {'char', 'string'}, {'scalartext'});
+
+    [localpath, ~, ~] = fileparts(source);
+    assert(2 == exist(source, 'file'),...
+        'MATNWB:FILE', 'Path to file `%s` could not be found.', source);
+    fid = fopen(source);
+    namespaceText = fread(fid, '*char') .';
+    fclose(fid);
+
+    Namespace = spec.generate(namespaceText, localpath);
+    file.writeNamespace(Namespace.name);
+    rehash();
+end
 end