SequenceDiagram: Add support for multiple alt else statements

dist/index.html

@@ -30,7 +30,18 @@
 Bob-x John: I am good thanks!
 Note right of John: Bob thinks a long<br/>long time, so long<br/>that the text does<br/>not fit on a row.
 Bob-->Alice: Checking with John...
-Alice->John: Yes... John, how are you?
+alt either this
+Alice->>John: Yes
+else or this
+Alice->>John: No
+else or this will happen
+Alice->John: Maybe
+end
+par this happens in parallel
+Alice -->> Bob: Parallel message 1
+and 
+Alice -->> John: Parallel message 2
+end
   </div>
 
   <hr/>

package.json

@@ -19,6 +19,7 @@
     "upgrade": "yarn-upgrade-all",
     "lint": "standard",
     "test": "yarn lint && jest",
+    "test:tdd": "yarn lint && jest --watch",
     "jison": "node -r babel-register node_modules/.bin/gulp jison",
     "prepublishOnly": "yarn build && yarn release && yarn test",
     "prepush": "yarn test"

src/diagrams/sequence/parser/sequenceDiagram.jison

@@ -104,18 +104,13 @@ statement
 		$3.unshift({type: 'optStart', optText:$2, signalType: yy.LINETYPE.OPT_START});
 		$3.push({type: 'optEnd', optText:$2, signalType: yy.LINETYPE.OPT_END});
 		$$=$3;}
-	| alt restOfLine document else restOfLine document end
+	| alt restOfLine else_sections end
 	{
 		// Alt start
 		$3.unshift({type: 'altStart', altText:$2, signalType: yy.LINETYPE.ALT_START});
 		// Content in alt is already in $3
-		// Else
-		$3.push({type: 'else', altText:$5, signalType: yy.LINETYPE.ALT_ELSE});
-		// Content in other alt
-		$3 = $3.concat($6);
 		// End
 		$3.push({type: 'altEnd', signalType: yy.LINETYPE.ALT_END});
-
 		$$=$3;}
 	| par restOfLine par_sections end
 	{
@@ -133,6 +128,12 @@ par_sections
 	{ $$ = $1.concat([{type: 'and', parText:$3, signalType: yy.LINETYPE.PAR_AND}, $4]); }
 	;
 
+else_sections
+	: document
+	| document else restOfLine else_sections
+	{ $$ = $1.concat([{type: 'else', altText:$3, signalType: yy.LINETYPE.ALT_ELSE}, $4]); }
+	;
+
 note_statement
 	: 'note' placement actor text2
 	{

src/diagrams/sequence/sequenceDiagram.spec.js

@@ -349,7 +349,7 @@ describe('when parsing a sequenceDiagram', function () {
     expect(messages[2].from).toBe('Bob')
     expect(messages[2].to).toBe('Alice')
   })
-  it('it should handle loop statements a sequenceDiagram', function () {
+  it('it should handle loop statements', function () {
     const str = 'sequenceDiagram\n' +
       'Alice->Bob: Hello Bob, how are you?\n\n' +
       '%% Comment\n' +
@@ -369,7 +369,7 @@ describe('when parsing a sequenceDiagram', function () {
     expect(messages[0].from).toBe('Alice')
     expect(messages[1].from).toBe('Bob')
   })
-  it('it should handle opt statements a sequenceDiagram', function () {
+  it('it should handle opt statements', function () {
     const str = 'sequenceDiagram\n' +
       'Alice->Bob: Hello Bob, how are you?\n\n' +
       '%% Comment\n' +
@@ -389,7 +389,7 @@ describe('when parsing a sequenceDiagram', function () {
     expect(messages[0].from).toBe('Alice')
     expect(messages[1].from).toBe('Bob')
   })
-  it('it should handle alt statements a sequenceDiagram', function () {
+  it('it should handle alt statements', function () {
     const str = 'sequenceDiagram\n' +
       'Alice->Bob: Hello Bob, how are you?\n\n' +
       '%% Comment\n' +
@@ -412,6 +412,30 @@ describe('when parsing a sequenceDiagram', function () {
     expect(messages[0].from).toBe('Alice')
     expect(messages[1].from).toBe('Bob')
   })
+  it('it should handle alt statements with multiple elses', function () {
+    const str = 'sequenceDiagram\n' +
+      'Alice->Bob: Hello Bob, how are you?\n\n' +
+      '%% Comment\n' +
+      'Note right of Bob: Bob thinks\n' +
+      'alt isWell\n\n' +
+      'Bob-->Alice: I am good thanks!\n' +
+      'else isSick\n' +
+      'Bob-->Alice: Feel sick...\n' +
+      'else default\n' +
+      'Bob-->Alice: :-)\n' +
+      'end'
+    parser.parse(str)
+    const messages = parser.yy.getMessages()
+    expect(messages.length).toBe(9)
+    expect(messages[1].from).toBe('Bob')
+    expect(messages[2].type).toBe(parser.yy.LINETYPE.ALT_START)
+    expect(messages[3].from).toBe('Bob')
+    expect(messages[4].type).toBe(parser.yy.LINETYPE.ALT_ELSE)
+    expect(messages[5].from).toBe('Bob')
+    expect(messages[6].type).toBe(parser.yy.LINETYPE.ALT_ELSE)
+    expect(messages[7].from).toBe('Bob')
+    expect(messages[8].type).toBe(parser.yy.LINETYPE.ALT_END)
+  })
   it('it should handle par statements a sequenceDiagram', function () {
     const str = 'sequenceDiagram\n' +
       'par Parallel one\n' +