4 files changed, 28 insertions, 3 deletions
diff --git a/polymatrix/expression/to.py b/polymatrix/expression/to.py
index 2707fb4..b1de626 100644
--- a/polymatrix/expression/to.py
+++ b/polymatrix/expression/to.py
@@ -76,4 +76,4 @@ def to_sympy(
             return state, m[0, 0]
         
         return state, m
-    return init_state_monad(polymatrix_to_sympy)
+    return init_state_monad(polymatrix_to_sympy, expr)
diff --git a/polymatrix/statemonad/impl.py b/polymatrix/statemonad/impl.py
index 14ad503..1b78daa 100644
--- a/polymatrix/statemonad/impl.py
+++ b/polymatrix/statemonad/impl.py
@@ -1,4 +1,4 @@
-from typing import Callable
+from typing import Callable, Any, Iterable
 import dataclassabc
 
 from polymatrix.statemonad.abc import StateMonad
@@ -7,3 +7,14 @@ from polymatrix.statemonad.abc import StateMonad
 @dataclassabc.dataclassabc(frozen=True)
 class StateMonadImpl(StateMonad):
     apply_func: Callable
+    arguments: Any | None = None
+
+    def __str__(self):
+        if not self.arguments:
+            return super().__str__(self)
+
+        args = str(self.arguments)
+        if isinstance(self.arguments, Iterable):
+            args = ", ".join(map(str, self.arguments))
+
+        return f"{str(self.apply_func.__name__)}({args})"
diff --git a/polymatrix/statemonad/init.py b/polymatrix/statemonad/init.py
index f3a8bd6..0abe6e4 100644
--- a/polymatrix/statemonad/init.py
+++ b/polymatrix/statemonad/init.py
@@ -1,11 +1,13 @@
-from typing import Callable
+from typing import Callable, Any
 
 from polymatrix.statemonad.impl import StateMonadImpl
 
 
 def init_state_monad(
     apply_func: Callable,
+    arguments: Any | None = None
 ):
     return StateMonadImpl(
         apply_func=apply_func,
+        arguments=arguments,
     )
diff --git a/polymatrix/statemonad/mixins.py b/polymatrix/statemonad/mixins.py
index e2bfda9..68d1db6 100644
--- a/polymatrix/statemonad/mixins.py
+++ b/polymatrix/statemonad/mixins.py
@@ -44,6 +44,18 @@ class StateMonadMixin(
         # NP: TODO comment
         ...
 
+    @property
+    @abc.abstractmethod
+    def arguments(self) -> U | None:
+        # arguments that were given to the function apply_func.
+        # this field is optional
+
+        # TODO: review this. It was added because I want to be able to see what
+        # was passed to the statemonads that are applied to expressions. For
+        # example in to_sympy, you want so see what expression is converted to
+        # sympy.
+        ...
+
     # NP: typing, use from __future__ import annotations
     def map(self, fn: Callable[[U], V]) -> 'StateMonadMixin[State, V]':
         # NP: add functools.wrap(fn) decorator to copy docstrings etc.