Add exampleEntities method in markdown renderer

Author: alvinsw

lib/profile.js

@@ -1,6 +1,8 @@
+const { ROCrate } = require('ro-crate');
 const rules = require('./rules');
 const {validateEntity} = require('./validator');
 const fs = require('fs');
+const path = require('path');
 
 
 /**
@@ -27,8 +29,36 @@ class LdacProfile {
       }
       ruleText[key] = text;
     }
+    // load examples
+    const examples = {};
+    for (const dir of fs.readdirSync('examples')) {
+      const cratePath = path.join('examples', dir, 'ro-crate-metadata.json');
+      try {
+        const json = JSON.parse(fs.readFileSync(cratePath, 'utf8'));
+        examples[dir] = new ROCrate(json, {array: true, link: true});
+      } catch (error) {
+      }
+    }
+    function exampleEntities(exampleName, entityIds) {
+      var result = '';
+      if (exampleName && examples[exampleName]) {
+        entityIds = [].concat(entityIds);
+        let part = '';
+        for (const id of entityIds) {
+          const entity = examples[exampleName].getEntity(id);
+          if (entity) {
+            part += '```json\n' + JSON.stringify(entity.toJSON(), null, 2) + '\n```\n';
+          }
+        }
+        if (part) {
+          part += `[source](../example/${exampleName}/README.md)\n\n`;
+          result += part;
+        }
+      }
+      return result;
+    }
     const template = fs.readFileSync(templatePath || 'templates/profile.md');
-    return (new Function('rules', 'return `' + template + '`;'))(ruleText);
+    return (new Function('rules', 'exampleEntities', 'return `' + template + '`;'))(ruleText, exampleEntities);
   }
 
   static generateDescribo() {

package.json

@@ -7,7 +7,8 @@
     "ldac-check": "./ldac-check.js"
   },
   "scripts": {
-    "test": "mocha"
+    "test": "mocha",
+    "build-spec": "node make-profile.js"
   },
   "repository": {
     "type": "git",

profile-text/profile.md

@@ -262,7 +262,7 @@ works) that may be included - \`PrimaryMaterial\` - which is a recording or
 original text, or a citation of or proxy for it, \`DerivedMaterial\` which
 has been generated or sampled from primary material by a process such as format
 conversion or digitization, and \`Annotation\`, which contains one or more types of
-analysis of the `\PrimaryMaterial`\ or `\DerivedMaterial`\.
+analysis of the \`PrimaryMaterial\` or \`DerivedMaterial\`.
 
 ### PrimaryMaterial