Add rule for orphan code lines

lib/makeSchema.js

@@ -9,13 +9,53 @@ const Slate = require('slate');
 function makeSchema(opts) {
     return {
         rules: [
-            noMarks(opts),
+            noOrphanLine(opts),
             onlyLine(opts),
-            onlyText(opts)
+            onlyText(opts),
+            noMarks(opts)
         ]
     };
 }
 
+/**
+ * @return {Object} A rule that ensure code lines are always children
+ * of a code block.
+ */
+function noOrphanLine(opts) {
+
+    return {
+        // Match all blocks that are not code blocks
+        match(node) {
+            return (node.kind === 'block' || node.kind === 'document')
+                && node.type !== opts.containerType;
+        },
+
+        validate(node) {
+            const codeLines = node.nodes.filter(n => n.type === opts.lineType);
+
+            if (codeLines.isEmpty()) {
+                // All good
+                return null;
+            } else {
+                // Wrap the orphan lines
+                return {
+                    toWrap: codeLines
+                };
+            }
+        },
+
+        /**
+         * Wrap the given blocks in code containers
+         * @param {List<Nodes>} value.toWrap
+         */
+        normalize(transform, node, value) {
+            return value.toWrap.reduce((tr, n) => {
+                return tr.wrapBlockByKey(n.key, opts.containerType);
+            }, transform);
+        }
+    };
+}
+
 /**
  * @return {Object} A rule that ensure code blocks only contain lines of code, and no marks
  */

tests/schema-no-orphan-line/expected.yaml

@@ -0,0 +1,18 @@
+
+nodes:
+  - kind: block
+    type: code_block
+    nodes:
+      - kind: block
+        type: code_line
+        nodes:
+          - kind: text
+            text: "Some orphan code"
+  - kind: block
+    type: code_block
+    nodes:
+      - kind: block
+        type: code_line
+        nodes:
+          - kind: text
+            text: "Some other code"

tests/schema-no-orphan-line/input.yaml

@@ -0,0 +1,15 @@
+
+nodes:
+  - kind: block
+    type: code_line
+    nodes:
+      - kind: text
+        text: "Some orphan code"
+  - kind: block
+    type: code_block
+    nodes:
+      - kind: block
+        type: code_line
+        nodes:
+          - kind: text
+            text: "Some other code"

tests/schema-no-orphan-line/transform.js

@@ -0,0 +1,8 @@
+const Slate = require('slate');
+
+module.exports = function(plugin, state) {
+    const schema = new Slate.Schema(plugin.schema);
+    return state.transform()
+        .normalize(schema)
+        .apply();
+};