Create NamedExpr and polymatrix.give_name to give shorter names to expressions

1 files changed, 32 insertions, 0 deletions

diff --git a/polymatrix/expression/mixins/namedexprmixin.py b/polymatrix/expression/mixins/namedexprmixin.py
new file mode 100644
index 0000000..e6d7284
--- /dev/null
+++ b/polymatrix/expression/mixins/namedexprmixin.py
@@ -0,0 +1,32 @@
+from __future__ import annotations
+
+from abc import abstractmethod
+from typing_extensions import override
+
+from polymatrix.expression.mixins.expressionbasemixin import ExpressionBaseMixin
+from polymatrix.expressionstate import ExpressionState
+from polymatrix.polymatrix.index import PolyDict, MonomialIndex
+from polymatrix.polymatrix.init import init_broadcast_poly_matrix
+from polymatrix.polymatrix.mixins import PolyMatrixMixin
+
+class NamedExprMixin(ExpressionBaseMixin):
+    """
+    Give a name to an expression.
+
+    This is mostly to make the printing more understandable.
+    See also NamedExprImpl.__str__.
+    """
+
+    @property
+    @abstractmethod
+    def underlying(self) -> ExpressionBaseMixin:
+        """ The expresssion """
+
+    @property
+    @abstractmethod
+    def name(self) -> str:
+        """ The name for the expression """
+
+    @override
+    def apply(self, state: ExpressionState) -> tuple[ExpressionState, PolyMatrixMixin]:
+        return self.underlying.apply(state)