diff --git a/src/grammar/GpslLexer.g4 b/src/grammar/GpslLexer.g4
index b33dbe4..cab0041 100644
--- a/src/grammar/GpslLexer.g4
+++ b/src/grammar/GpslLexer.g4
@@ -5,6 +5,7 @@ WS
       -> skip
     ;
 
+SHARP: '#' ;
 DOLLER: '$' ;
 ADD: '+' ;
 SUB: '-' ;
diff --git a/src/grammar/GpslParser.g4 b/src/grammar/GpslParser.g4
index bf18158..9a73d1a 100644
--- a/src/grammar/GpslParser.g4
+++ b/src/grammar/GpslParser.g4
@@ -17,12 +17,13 @@ stmt: let
     ;
 
 let: LET IDENT COLON IDENT SEMICOLON ;
-block: permission? LCURL stmt* RCURL ;
+block: permission? mode? LCURL stmt* RCURL ;
 return: RETURN expr? SEMICOLON ;
 if: IF LPAREN expr RPAREN stmt (ELSE stmt)? ;
 while: WHILE LPAREN expr RPAREN stmt ;
 for: FOR LPAREN expr? SEMICOLON expr? SEMICOLON expr? RPAREN stmt ;
 
+mode: SHARP IDENT ;
 permission: DOLLER LPAREN ( IDENT LBRACKET ( IDENT COMMA? )* RBRACKET COMMA? )* RPAREN ;
 
 expr: assign ;
diff --git a/src/node.rs b/src/node.rs
index d6dcc92..3ec8bca 100644
--- a/src/node.rs
+++ b/src/node.rs
@@ -20,6 +20,9 @@ pub enum Node {
         args: HashMap<String, String>,
         body: Vec<Box<Node>>
     },
+    Mode {
+        mode: String
+    },
     Permission {
         accept: Vec<String>,
         reject: Vec<String>
@@ -58,7 +61,8 @@ pub enum Node {
     },
     Block {
         stmts: Vec<Box<Node>>,
-        permission: Option<Box<Node>>
+        permission: Option<Box<Node>>,
+        mode: Option<Box<Node>>,
     },
     Define {
         name: String,
diff --git a/src/parser.rs b/src/parser.rs
index 34d055a..5ef4cf8 100644
--- a/src/parser.rs
+++ b/src/parser.rs
@@ -110,6 +110,13 @@ impl Parser {
             None
         };
 
+        debug!("parsing mode");
+        let mode = if self.tokenizer.current_token().str == "#" {
+            Some(self.mode()?)
+        } else {
+            None
+        };
+
         if self
             .tokenizer
             .consume_kind_str(TokenKind::RESERVED, String::from("{")) || permission != None
@@ -120,7 +127,7 @@ impl Parser {
                     .tokenizer
                     .consume_kind_str(TokenKind::RESERVED, String::from("}"))
                 {
-                    return Ok(Box::new(Node::Block { stmts, permission: permission }));
+                    return Ok(Box::new(Node::Block { stmts, permission: permission, mode: mode }));
                 } else {
                     stmts.push(self.stmt()?);
                 }
@@ -207,6 +214,16 @@ impl Parser {
         return node;
     }
 
+    /*
+        mode: SHARP IDENT ;
+     */
+    pub fn mode(&mut self) -> Result<Box<Node>, String> {
+        self.tokenizer.expect(String::from("#"))?;
+        let mode = self.tokenizer.current_token().clone();
+        self.tokenizer.expect_kind(TokenKind::IDENT)?;
+        return Ok(Box::new(Node::Mode { mode: mode.str }));
+    }
+
     /*
         permission: DOLLER LPAREN ( IDENT LBRACKET ( IDENT COMMA? )* RBRACKET COMMA? )* RPAREN ;
     */
diff --git a/src/tokenizer.rs b/src/tokenizer.rs
index a17ae8c..d51e6e5 100644
--- a/src/tokenizer.rs
+++ b/src/tokenizer.rs
@@ -113,6 +113,7 @@ impl Tokenizer {
             String::from("-="),
             String::from("*="),
             String::from("/="),
+            String::from("#"),
             String::from("$"),
             String::from("+"),
             String::from("-"),
diff --git a/src/vm/gpsl.rs b/src/vm/gpsl.rs
index d523ff7..576aac3 100644
--- a/src/vm/gpsl.rs
+++ b/src/vm/gpsl.rs
@@ -458,7 +458,7 @@ impl GPSL {
 
                 return Ok(None);
             }
-            Node::Block { stmts, permission } => {
+            Node::Block { stmts, permission, mode } => {
                 let accept = self.blocks.front().unwrap().accept.clone();
                 let reject = self.blocks.front().unwrap().reject.clone();
                 let (accept, reject) = if let Node::Permission { accept, reject } = *permission.unwrap_or(Box::new(Node::None)) {
@@ -467,6 +467,8 @@ impl GPSL {
                     (accept, reject)
                 };
 
+                if let Node::Mode { mode } = *mode.unwrap_or(Box::new(Node::None)) {}
+
                 self.blocks.push_front(Block {
                     accept: accept,
                     reject: reject,