Синтаксический сахар - доступ к элементам map через точку

Author: aNNiMON

examples/network/github_timeline.own

@@ -19,42 +19,42 @@ thread(::http, "https://api.github.com/events", def(r) {
 })
 
 def show_github_events(event) {
-    println event["created_at"]
-    actor = event["actor"]
-    println "User: https://github.com/" + actor["login"]
+    println event.created_at
+    actor = event.actor
+    println "User: https://github.com/" + actor.login
     println github_event_type(event)
     println "-" * 50
 }
 
 def github_event_type(event) {
-    type = event["type"]
-    repo = "https://github.com/" + event["repo"]["name"]
-    payload = event["payload"]
+    type = event.type
+    repo = "https://github.com/" + event.repo.name
+    payload = event.payload
 
     if (type == "CommitCommentEvent") {
-      return "commented commit in " + repo + "\n" + payload["comment"]["body"]
+      return "commented commit in " + repo + "\n" + payload.comment.body
     }
     if (type == "CreateEvent") {
-      return "created " + payload["ref_type"] + " on " + repo
+      return "created " + payload.ref_type + " on " + repo
     }
     if (type == "DeleteEvent") {
-      return "deleted " + payload["ref_type"] + " on " + repo
+      return "deleted " + payload.ref_type + " on " + repo
     }
     if (type == "ForkEvent") {
       return "forked repository " + repo
     }
     if (type == "IssueCommentEvent") {
-      return "commented issue " + payload["issue"]["title"] + " on " + repo + "\n" + payload["comment"]["body"]
+      return "commented issue " + payload.issue.title + " on " + repo + "\n" + payload.comment.body
     }
     if (type == "IssuesEvent") {
-      return payload["action"] + " issue '" + payload["issue"]["title"] + "' on " + repo
+      return payload.action + " issue '" + payload.issue.title + "' on " + repo
     }
     if (type == "PullRequestEvent") {
-      pr = payload["pull_request"]
-      return payload["action"] + " pull request #" + payload["number"] + " '" + pr["title"] + "' on " + repo
+      pr = payload.pull_request
+      return payload.action + " pull request #" + payload.number + " '" + pr.title + "' on " + repo
     }
     if (type == "PushEvent") {
-      return "pushed " + length(payload["commits"]) + " commits to " + repo
+      return "pushed " + length(payload.commits) + " commits to " + repo
     }
     if (type == "WatchEvent") {
       return "start watching repository " + repo

src/com/annimon/ownlang/parser/Lexer.java

@@ -11,7 +11,7 @@
  */
 public final class Lexer {
 
-    private static final String OPERATOR_CHARS = "+-*/%()[]{}=<>!&|,^~?:";
+    private static final String OPERATOR_CHARS = "+-*/%()[]{}=<>!&|.,^~?:";
 
     private static final Map<String, TokenType> OPERATORS;
     static {
@@ -30,6 +30,7 @@ public final class Lexer {
         OPERATORS.put("=", TokenType.EQ);
         OPERATORS.put("<", TokenType.LT);
         OPERATORS.put(">", TokenType.GT);
+        OPERATORS.put(".", TokenType.DOT);
         OPERATORS.put(",", TokenType.COMMA);
         OPERATORS.put("^", TokenType.CARET);
         OPERATORS.put("~", TokenType.TILDE);

src/com/annimon/ownlang/parser/Parser.java

@@ -237,6 +237,19 @@ private ArrayAccessExpression element() {
         return new ArrayAccessExpression(variable, indices);
     }
 
+    private ArrayAccessExpression object() {
+        // object.field1.field2
+        // Syntaxic sugar for object["field1"]["field2"]
+        final String variable = consume(TokenType.WORD).getText();
+        final List<Expression> indices = new ArrayList<>();
+        while (match(TokenType.DOT)) {
+            final String fieldName = consume(TokenType.WORD).getText();
+            final Expression key = new ValueExpression(fieldName);
+            indices.add(key);
+        }
+        return new ArrayAccessExpression(variable, indices);
+    }
+    
     private Expression expression() {
         return ternary();
     }
@@ -459,6 +472,9 @@ private Expression primary() {
         if (lookMatch(0, TokenType.WORD) && lookMatch(1, TokenType.LPAREN)) {
             return function();
         }
+        if (lookMatch(0, TokenType.WORD) && lookMatch(1, TokenType.DOT)) {
+            return object();
+        }
         if (lookMatch(0, TokenType.LBRACKET)) {
             return array();
         }

src/com/annimon/ownlang/parser/TokenType.java

@@ -61,6 +61,7 @@ public enum TokenType {
     LBRACE, // {
     RBRACE, // }
     COMMA, // ,
+    DOT, // .
 
     EOF
 }