Add Lattice class

src/pals/kinds/Lattice.py

@@ -0,0 +1,39 @@
+from pydantic import model_validator, Field
+from typing import Annotated, List, Literal, Union
+
+from .BeamLine import BeamLine
+from .mixin import BaseElement
+from ..functions import load_file_to_dict, store_dict_to_file
+
+
+class Lattice(BaseElement):
+    """A line of elements and/or other lines"""
+
+    kind: Literal["Lattice"] = "Lattice"
+
+    branches: List[Annotated[Union[BeamLine], Field(discriminator="kind")]]
+
+    @model_validator(mode="before")
+    @classmethod
+    def unpack_json_structure(cls, data):
+        """Deserialize the JSON/YAML/...-like dict for Lattice elements"""
+        from pals.kinds.mixin.all_element_mixin import unpack_element_list_structure
+
+        return unpack_element_list_structure(data, "branches", "branches")
+
+    def model_dump(self, *args, **kwargs):
+        """Custom model dump for Lattice to handle element list formatting"""
+        from pals.kinds.mixin.all_element_mixin import dump_element_list
+
+        return dump_element_list(self, "branches", *args, **kwargs)
+
+    @staticmethod
+    def from_file(filename: str) -> "Lattice":
+        """Load a Lattice from a text file"""
+        pals_dict = load_file_to_dict(filename)
+        return Lattice(**pals_dict)
+
+    def to_file(self, filename: str):
+        """Save a Lattice to a text file"""
+        pals_dict = self.model_dump()
+        store_dict_to_file(filename, pals_dict)

src/pals/kinds/__init__.py

@@ -5,6 +5,7 @@
 from .ACKicker import ACKicker  # noqa: F401
 from .BeamBeam import BeamBeam  # noqa: F401
 from .BeamLine import BeamLine  # noqa: F401
+from .Lattice import Lattice  # noqa: F401
 from .BeginningEle import BeginningEle  # noqa: F401
 from .Converter import Converter  # noqa: F401
 from .CrabCavity import CrabCavity  # noqa: F401
@@ -39,3 +40,4 @@
 # Rebuild pydantic models that depend on other classes
 UnionEle.model_rebuild()
 BeamLine.model_rebuild()
+Lattice.model_rebuild()

src/pals/kinds/all_elements.py

@@ -43,6 +43,7 @@
 def get_all_element_types(extra_types: tuple = None):
     """Return a tuple of all element types that can be used in BeamLine or UnionEle."""
     element_types = (
+        "Lattice",  # Forward reference to handle circular import
         "BeamLine",  # Forward reference to handle circular import
         "UnionEle",  # Forward reference to handle circular import
         ACKicker,

tests/test_elements.py

@@ -511,3 +511,29 @@ def test_UnionEle():
     assert len(element_with_children.elements) == 2
     assert element_with_children.elements[0].name == "m1"
     assert element_with_children.elements[1].name == "d1"
+
+
+def test_Lattice():
+    # Create first line with one base element
+    element1 = pals.Marker(name="element1")
+    line1 = pals.BeamLine(name="line1", line=[element1])
+    assert line1.line == [element1]
+    # Extend first line with one thick element
+    element2 = pals.Drift(name="element2", length=2.0)
+    line1.line.extend([element2])
+    assert line1.line == [element1, element2]
+    # Create second line with one drift element
+    element3 = pals.Drift(name="element3", length=3.0)
+    line2 = pals.BeamLine(name="line2", line=[element3])
+    # Extend first line with second line
+    line1.line.extend(line2.line)
+    assert line1.line == [element1, element2, element3]
+    # Build lattice with two lines
+    lattice = pals.Lattice(name="lattice", branches=[line1, line2])
+    assert lattice.name == "lattice"
+    assert lattice.kind == "Lattice"
+    assert len(lattice.branches) == 2
+    assert lattice.branches[0].name == "line1"
+    assert lattice.branches[1].name == "line2"
+    assert lattice.branches[0].line == [element1, element2, element3]
+    assert lattice.branches[1].line == [element3]