diff --git a/rflx/abstract_expression.py b/rflx/abstract_expression.py
new file mode 100644
index 000000000..97518c7d3
--- /dev/null
+++ b/rflx/abstract_expression.py
@@ -0,0 +1,386 @@
+# pylint: disable=too-many-ancestors
+
+from __future__ import annotations
+
+from abc import abstractmethod
+
+from rflx import typing_ as rty
+from rflx.common import Base
+from rflx.contract import DBC
+
+
+class AbstractExpr(DBC, Base):
+    @abstractmethod
+    def __init__(self, type_: rty.Type = rty.Undefined()):
+        self.type_ = type_
+
+    @classmethod
+    @abstractmethod
+    def create_not(cls, expr: AbstractExpr) -> AbstractNot:
+        raise NotImplementedError
+
+
+class AbstractNot(AbstractExpr):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractBinExpr(AbstractExpr):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractAssExpr(AbstractExpr):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractBoolAssExpr(AbstractAssExpr):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractAnd(AbstractBoolAssExpr):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractAndThen(AbstractAnd):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractOr(AbstractBoolAssExpr):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractOrElse(AbstractOr):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractNumber(AbstractExpr):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractMathAssExpr(AbstractAssExpr):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractAdd(AbstractMathAssExpr):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractMul(AbstractMathAssExpr):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractMathBinExpr(AbstractBinExpr):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractSub(AbstractMathBinExpr):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractDiv(AbstractMathBinExpr):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractPow(AbstractMathBinExpr):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractMod(AbstractMathBinExpr):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractRem(AbstractMathBinExpr):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractName(AbstractExpr):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractLiteral(AbstractName):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractVariable(AbstractName):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractAttribute(AbstractName):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractSize(AbstractAttribute):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractLength(AbstractAttribute):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractFirst(AbstractAttribute):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractLast(AbstractAttribute):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractValidChecksum(AbstractAttribute):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractValid(AbstractAttribute):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractPreset(AbstractAttribute):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractHasData(AbstractAttribute):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractHead(AbstractAttribute):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractOpaque(AbstractAttribute):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractConstrained(AbstractAttribute):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractVal(AbstractAttribute):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractIndexed(AbstractName):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractSelected(AbstractName):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractCall(AbstractName):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractSlice(AbstractName):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractAggregate(AbstractExpr):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractString(AbstractAggregate):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractNamedAggregate(AbstractExpr):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractRelation(AbstractBinExpr):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractLess(AbstractRelation):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractLessEqual(AbstractRelation):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractEqual(AbstractRelation):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractGreaterEqual(AbstractRelation):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractGreater(AbstractRelation):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractNotEqual(AbstractRelation):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractIn(AbstractRelation):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractNotIn(AbstractRelation):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractIfExpr(AbstractExpr):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractQuantifiedExpr(AbstractExpr):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractForAllOf(AbstractQuantifiedExpr):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractForAllIn(AbstractQuantifiedExpr):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractForSomeIn(AbstractQuantifiedExpr):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractValueRange(AbstractExpr):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractConversion(AbstractExpr):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractQualifiedExpr(AbstractExpr):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractComprehension(AbstractExpr):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractMessageAggregate(AbstractExpr):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass
+
+
+class AbstractDeltaMessageAggregate(AbstractExpr):
+    @abstractmethod
+    def __init__(self) -> None:
+        pass