diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 1c84905ad..70676f2b7 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -17,6 +17,8 @@ jobs:
       run: |
         python -m pip install --upgrade pip
         python -m pip install -r ./requirements.txt
+    - name: Generate parser
+      run: antlr4 -Dlanguage=Python3 project/langRules.yaml -visitor -o project/lang
     - name: Test with pytest
       run: |
         python ./scripts/run_tests.py
diff --git a/project/langRules.yaml b/project/langRules.yaml
new file mode 100644
index 000000000..586c92ab5
--- /dev/null
+++ b/project/langRules.yaml
@@ -0,0 +1,21 @@
+grammar langRules;
+
+prog: stmt*;
+
+stmt: bind | add | remove | declare;
+	declare: 'let' VAR 'is' 'graph';
+	bind: 'let' VAR '=' expr;
+	remove: 'remove' ('vertex' | 'edge' | 'vertices') expr 'from' VAR;
+	add: 'add' ('vertex' | 'edge') expr 'to' VAR;
+
+expr: NUM | CHAR | VAR | edge_expr | set_expr | regexp | select;
+	set_expr: '[' expr (',' expr)* ']';
+	edge_expr: '(' expr ',' expr ',' expr ')';
+	regexp: CHAR | VAR | '(' regexp ')' | regexp '|' regexp | regexp '^' range | regexp '.' regexp | regexp '&' regexp;
+		range: '[' NUM '..' NUM? ']';
+	select: v_filter? v_filter? 'return' VAR (',' VAR)? 'where' VAR 'reachable' 'from' VAR 'in' VAR 'by' expr;
+		v_filter: 'for' VAR 'in' expr;
+
+VAR: [a-z] [a-z0-9]*;
+NUM: ([1-9][0-9]*) | '0';
+CHAR: '\u0022' [a-z] '\u0022';
diff --git a/project/task11.py b/project/task11.py
new file mode 100644
index 000000000..06e88bd50
--- /dev/null
+++ b/project/task11.py
@@ -0,0 +1,41 @@
+from project.lang.project.languageVisitor import languageVisitor
+from project.lang.project.languageLexer import languageLexer
+from project.lang.project.languageParser import languageParser
+
+from antlr4 import *
+from antlr4.InputStream import InputStream
+
+
+class NodeCounter(languageVisitor):
+    def __init__(self):
+        super().__init__()
+        self.counter = 0
+
+    def enterEveryRule(self, _):
+        self.counter += 1
+
+
+class TreeToProgVisitor(languageVisitor):
+    def __init__(self):
+        super().__init__()
+        self.visits = []
+
+    def enterEveryRule(self, rule):
+        self.visits.append(rule.get_text())
+
+
+def nodes_count(tree: ParserRuleContext) -> int:
+    visitor = NodeCounter()
+    tree.accept(visitor)
+    return visitor.counter
+
+
+def tree_to_prog(tree: ParserRuleContext) -> str:
+    visitor = TreeToProgVisitor()
+    tree.accept(visitor)
+    return "".join(visitor.visits)
+
+
+def prog_to_tree(program: str) -> tuple[ParserRuleContext, bool]:
+    parser = languageParser(CommonTokenStream(languageLexer(InputStream(program))))
+    return parser.prog(), parser.getNumberOfSyntaxErrors() == 0
diff --git a/requirements.txt b/requirements.txt
index 04c4f5c00..bf66ffb80 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,4 +1,5 @@
 antlr4-python3-runtime
+antlr4-tools
 black
 cfpq-data
 grammarinator @ git+https://github.com/renatahodovan/grammarinator.git@f3ffa71