new var declaration syntax

examples/brainfuck.zr

@@ -1,15 +1,15 @@
 func main[] : i64
     // https://brainfuck.org/sierpinski.b
-    let src = "++++++++[>+>++++<<-]>++>>+<[-[>>+<<-]+>>]>+[-<<<[->[+[-]+>++>>>-<<]<[<]>>++++++[<<+++++>>-]+<<++.[-]<<]>.>+[>>]>+]"
-    let src_len = str.len(src)
-    let i = 0
+    src := "++++++++[>+>++++<<-]>++>>+<[-[>>+<<-]+>>]>+[-<<<[->[+[-]+>++>>>-<<]<[<]>>++++++[<<+++++>>-]+<<++.[-]<<]>.>+[>>]>+]"
+    src_len := str.len(src)
+    i := 0
 
-    let memory = mem.alloc(30000)
+    memory := mem.alloc(30000)
     mem.zero(memory, 30000)
-    let p = 0
+    p := 0
 
     while i < src_len
-        let op = src[i]
+        op := src[i]
 
         if op == '>'
             p = p + 1
@@ -26,7 +26,7 @@ func main[] : i64
         else if op == '['
             if !memory[p]
                 i = i + 1
-                let opened = 0
+                opened := 0
                 while i < src_len && !(src[i] == ']' && !opened)
                     if src[i] == '['
                         opened = opened + 1
@@ -36,7 +36,7 @@ func main[] : i64
         else if op == ']'
             if memory[p]
                 i = i - 1
-                let closed = 0
+                closed := 0
                 while i >= 0 && !(src[i] == '[' && !closed)
                     if src[i] == ']'
                         closed = closed + 1