Add abbility to register own processors to modify the styleguide data

Resolves #898

README.md

@@ -318,6 +318,40 @@ For example, to parse all .css files using postcss parser, following configurati
 }
 ```
 
+<a name="option-styleguideProcessors"></a>
+**styleguideProcessors** (object, optional)
+
+default:
+
+```js
+styleguideProcessors: {}
+```
+
+Styleguide has several processors that enrich or modify the data. For example the `sg-wrapper` replacement is done by a processor.
+You can add you own processor to enrich the styleguide data with you own content or modifications.
+You can also override existing functionality by overwriting the related processor.
+Currently these processors exist by default and should not be overwritten unless you know what you are doing:
+
+```js
+styleguideProcessors: {
+    10: replaceSectionReferences,
+    20: generateSectionWrapperMarkup
+}
+```
+
+You can define your own processors:
+
+```js
+styleguideProcessors: {
+  11: function() {
+    // this will run after replaceSectionReferences
+  },
+  30: function() {
+    // this will run after generateSectionWrapperMarkup
+  }
+}
+```
+
 <a name="option-filesConfig"></a>
 **filesConfig** (array, optional) **(Experimental feature)**
 

demo-gulpfile.js

@@ -15,6 +15,11 @@ gulp.task('styleguide:generate', function() {
         styleVariables: 'lib/app/css/_styleguide_variables.css',
         parsers: {
           css: 'postcss'
+        },
+        styleguideProcessors: {
+            40: function(styleguide) {
+                styleguide.sections[0].description = styleguide.sections[0].description + ' [Description from custom Processor]';
+            }
         }
       }))
     .pipe(gulp.dest(outputPath));

lib/modules/common.js

@@ -30,7 +30,8 @@ function sanitizeOptions(opt) {
       less: 'less',
       postcss: 'postcss'
     },
-    filesConfig: opt.filesConfig
+    filesConfig: opt.filesConfig,
+    styleguideProcessors: opt.styleguideProcessors || {}
   };
 }
 

lib/styleguide.js

@@ -224,7 +224,14 @@ module.exports.generate = function(options) {
     throughOpts = {
       objectMode: true,
       allowHalfOpen: false
-    };
+    },
+    styleguideProcessors = _.extend(
+        {
+          10: replaceSectionReferences,
+          20: generateSectionWrapperMarkup
+        },
+        opt.styleguideProcessors
+    );
 
   function bufferFileContents(file, enc, done) {
     if (file.isNull()) {
@@ -295,8 +302,11 @@ module.exports.generate = function(options) {
         }
 
         options.enableJade && generateJadeMarkup(styleguide, options);
-        replaceSectionReferences(styleguide);
-        generateSectionWrapperMarkup(styleguide);
+
+        _.each(styleguideProcessors, function(processor) {
+          processor(styleguide);
+        });
+
         copyUsedOptionsToJsonConfig(opt, styleguide);
         appendUsedVariablesToEachBlock(opt, styleguide);
         addFileHashesAndReplaceAbsolutePaths(styleguide);