diff --git a/controllers/pyctrl/samples/apalache.py b/controllers/pyctrl/samples/apalache.py
new file mode 100644
index 00000000..818ea473
--- /dev/null
+++ b/controllers/pyctrl/samples/apalache.py
@@ -0,0 +1,153 @@
+import pyaici.server as aici
+
+# note that VSCode syntax highlighting is not perfect r""" ... """ (it assumes regexp)
+apalache = r"""
+
+%start T
+%%
+
+SKIP
+    : "/\n?[ \t\v\f]*/" ; // white-space, newline, tabs, ...
+
+List
+    : T
+    | List "," T
+    ;
+
+T
+    // integers
+    : "Int"
+    // immutable constant strings
+    | "Str"
+    // boolean
+    | "Bool"
+    // functions
+    | T "->" T
+    // sets
+    | "Set" "(" T ")"
+    // sequences
+    | "Seq" "(" T ")"
+    // tuples
+    | "<<" List ">>"
+    // parentheses, e.g., to change associativity of functions
+    | "(" T ")"
+    // operators
+    | "(" T ")" "=>" T
+    | "(" List ")" "=>" T
+    ;
+%%
+"""
+
+t12 = r"""
+  
+// Prefix all reguluar expressions to disambiguate them.
+// The tool first tries a regex and only then looks at the grammar. :-(
+field
+    : "/f[a-zA-Z_][a-zA-Z0-9_]*/" ;
+
+typeConst
+    : "/t[A-Z_][A-Z0-9_]*/" ;
+
+typeVar
+    : "/v[a-z]?/" ;
+
+aliasName
+    : "/a[a-z]+(?:[A-Z][a-z]*)*/" ;
+
+T12  
+    // type all rules
+    : "$" aliasName
+    // constant types (uninterpreted types)
+    | typeConst
+    // type variables
+    | typeVar
+    // A new record type with a fully defined structure.
+    // The set of fields may be empty. If typeVar is present,
+    // the record type is parameterized (typeVar must be of the 'row' kind).
+    // | "{" field ":" T "," ..."," field ":" T ["," typeVar] "}"
+    // A variant that contains several options,
+    // optionally parameterized (typeVar must be of the "row" kind).
+    // | variantOption "|" ... "|" variantOption "|" [typeVar]
+    // A purely parameterized variant (typeVar must be of the "row" kind).
+    | "Variant" "(" typeVar ")"
+    ;
+  
+%%
+"""
+
+
+async def gen_and_test_grammar():
+    await aici.FixedTokens(
+        """
+            ---- MODULE Counter ----
+            VARIABLE
+                        b
+
+            Init == b = TRUE
+            Next == b' = FALSE
+            ====
+
+            The type of the variable declaration of b in the following TLA+ spec is:
+        """
+    )
+    tokens = await aici.gen_tokens(yacc=apalache, max_tokens=10, store_var="b")
+    print(tokens)
+
+    ## No need to tokenize the input, as it is already tokenized?!
+    # tokens = aici.tokenize(input)
+    constr = aici.CfgConstraint(apalache)
+    outp = []
+    for t in tokens:
+        print(f"Testing token: {t}")
+        if not constr.token_allowed(t):
+            ## Abort/terminate if token is not allowed.
+            print(f"Token {t} not allowed")
+            print("OK: " + repr(aici.detokenize(outp).decode("utf-8", "ignore")))
+            print("fail: " + repr(aici.detokenize([t]).decode("utf-8", "ignore")))
+            break
+        outp.append(t)
+        constr.append_token(t)
+    print(f"EOS allowed: {constr.eos_allowed()}")
+
+
+async def test_grammar():
+    await aici.FixedTokens("Start")
+    ## define a list of test inputs
+    inputs = [
+        "Int",
+        "Int",
+        "Str",
+        "(Int)",
+        "Bool",
+        "Int -> Int",
+        "Set(Int)",
+        "Seq(Int)",
+        "Set(Int) -> Set(Int)",
+        "Set(<<Int, Int>> -> Int)",
+        "<<Int,Int>>",
+        "(Int,Int) => Int",
+        "(Int,Bool) => Int",
+        "((Int,Bool) => Int) => Bool"
+        # "$aalias",
+        # "Variant(va)"
+    ]
+
+    ## loop over the inputs and test the grammar
+    for input in inputs:
+        print(f"Testing input: {input}")
+        tokens = aici.tokenize(input)
+        # print(tokens)
+        constr = aici.CfgConstraint(apalache)
+        outp = []
+        for t in tokens:
+            if not constr.token_allowed(t):
+                ## Abort/terminate if token is not allowed.
+                print(f"Token {t} not allowed")
+                print("OK: " + repr(aici.detokenize(outp).decode("utf-8", "ignore")))
+                print("fail: " + repr(aici.detokenize([t]).decode("utf-8", "ignore")))
+                break
+            outp.append(t)
+            constr.append_token(t)
+        print(f"EOS allowed: {constr.eos_allowed()}")
+
+aici.test(test_grammar())
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