6 files changed, 15 insertions, 134 deletions
diff --git a/gerbonara/gerber/aperture_macros/expression.py b/gerbonara/gerber/aperture_macros/expression.py
index 2375c56..f25fdd2 100644
--- a/gerbonara/gerber/aperture_macros/expression.py
+++ b/gerbonara/gerber/aperture_macros/expression.py
@@ -80,10 +80,10 @@ class UnitExpression(Expression):
         if self.unit is None or unit is None or self.unit == unit:
             return self._expr
 
-        elif unit == MM:
+        elif MM == unit:
             return self._expr * MILLIMETERS_PER_INCH
 
-        elif unit == Inch:
+        elif Inch == unit:
             return self._expr / MILLIMETERS_PER_INCH
 
         else:
diff --git a/gerbonara/gerber/cam.py b/gerbonara/gerber/cam.py
index 6fe5f9b..36e08ac 100644
--- a/gerbonara/gerber/cam.py
+++ b/gerbonara/gerber/cam.py
@@ -18,6 +18,8 @@
 from dataclasses import dataclass
 from copy import deepcopy
 
+from .utils import LengthUnit, MM, Inch
+
 @dataclass
 class FileSettings:
     '''
@@ -31,15 +33,15 @@ class FileSettings:
         `zeros='trailing'`
     '''
     notation : str = 'absolute'
-    unit : str = 'inch'
+    unit : LengthUnit = Inch
     angle_unit : str = 'degree'
     zeros : bool = None
     number_format : tuple = (2, 5)
 
     # input validation
     def __setattr__(self, name, value):
-        if name == 'unit' and value not in ['inch', 'mm']:
-            raise ValueError(f'Unit must be either "inch" or "mm", not {value}')
+        if name == 'unit' and value not in [MM, Inch]:
+            raise ValueError(f'Unit must be either Inch or MM, not {value}')
         elif name == 'notation' and value not in ['absolute', 'incremental']:
             raise ValueError(f'Notation must be either "absolute" or "incremental", not {value}')
         elif name == 'angle_unit' and value not in ('degree', 'radian'):
diff --git a/gerbonara/gerber/gerber_statements.py b/gerbonara/gerber/gerber_statements.py
index 55a4bf3..62aab3b 100644
--- a/gerbonara/gerber/gerber_statements.py
+++ b/gerbonara/gerber/gerber_statements.py
@@ -92,8 +92,7 @@ class ApertureMacroStmt(ParamStmt):
         self.macro = macro
 
     def to_gerber(self, settings):
-        unit = settings.unit if settings else None
-        return f'%AM{self.macro.name}*\n{self.macro.to_gerber(unit=unit)}*\n%'
+        return f'%AM{self.macro.name}*\n{self.macro.to_gerber(unit=settings.unit)}*\n%'
 
     def __str__(self):
         return f'<AM Aperture Macro {self.macro.name}: {self.macro}>'
diff --git a/gerbonara/gerber/layers.py b/gerbonara/gerber/layers.py
index c221324..35f2b00 100644
--- a/gerbonara/gerber/layers.py
+++ b/gerbonara/gerber/layers.py
@@ -295,7 +295,6 @@ class InternalLayer(PCBLayer):
         return (self.order <= other.order)
 
 class PCB:
-
     @classmethod
     def from_directory(cls, directory, board_name=None, verbose=False):
         layers = []
diff --git a/gerbonara/gerber/operations.py b/gerbonara/gerber/operations.py
deleted file mode 100644
index d06876e..0000000
--- a/gerbonara/gerber/operations.py
+++ /dev/null
@@ -1,126 +0,0 @@
-#!/usr/bin/env python
-# -*- coding: utf-8 -*-
-
-# copyright 2015 Hamilton Kibbe <ham@hamiltonkib.be>
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-
-#     http://www.apache.org/licenses/LICENSE-2.0
-
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-"""
-CAM File Operations
-===================
-**Transformations and other operations performed on Gerber and Excellon files**
-
-"""
-import copy
-
-
-def to_inch(cam_file):
-    """ Convert Gerber or Excellon file units to imperial
-
-    Parameters
-    ----------
-    cam_file : :class:`gerber.cam.CamFile` subclass
-        Gerber or Excellon file to convert
-
-    Returns
-    -------
-    cam_file : :class:`gerber.cam.CamFile` subclass
-        A deep copy of the source file with units converted to imperial.
-    """
-    cam_file = copy.deepcopy(cam_file)
-    cam_file.to_inch()
-    return cam_file
-
-
-def to_metric(cam_file):
-    """ Convert Gerber or Excellon file units to metric
-
-    Parameters
-    ----------
-    cam_file : :class:`gerber.cam.CamFile` subclass
-        Gerber or Excellon file to convert
-
-    Returns
-    -------
-    cam_file : :class:`gerber.cam.CamFile` subclass
-        A deep copy of the source file with units converted to metric.
-    """
-    cam_file = copy.deepcopy(cam_file)
-    cam_file.to_metric()
-    return cam_file
-
-
-def offset(cam_file, x_offset, y_offset):
-    """ Offset a Cam file by a specified amount in the X and Y directions.
-
-    Parameters
-    ----------
-    cam_file : :class:`gerber.cam.CamFile` subclass
-        Gerber or Excellon file to offset
-
-    x_offset : float
-        Amount to offset the file in the X direction
-
-    y_offset : float
-        Amount to offset the file in the Y direction
-
-    Returns
-    -------
-    cam_file : :class:`gerber.cam.CamFile` subclass
-        An offset deep copy of the source file.
-    """
-    cam_file = copy.deepcopy(cam_file)
-    cam_file.offset(x_offset, y_offset)
-    return cam_file
-
-
-def scale(cam_file, x_scale, y_scale):
-    """ Scale a Cam file by a specified amount in the X and Y directions.
-
-    Parameters
-    ----------
-    cam_file : :class:`gerber.cam.CamFile` subclass
-        Gerber or Excellon file to scale
-
-    x_scale : float
-        X-axis scale factor
-
-    y_scale : float
-        Y-axis scale factor
-
-    Returns
-    -------
-    cam_file : :class:`gerber.cam.CamFile` subclass
-        An scaled deep copy of the source file.
-    """
-    # TODO
-    pass
-
-
-def rotate(cam_file, angle):
-    """ Rotate a Cam file a specified amount about the origin.
-
-    Parameters
-    ----------
-    cam_file : :class:`gerber.cam.CamFile` subclass
-        Gerber or Excellon file to rotate
-
-    angle : float
-        Angle to rotate the file in degrees.
-
-    Returns
-    -------
-    cam_file : :class:`gerber.cam.CamFile` subclass
-        An rotated deep copy of the source file.
-    """
-    # TODO
-    pass
diff --git a/gerbonara/gerber/utils.py b/gerbonara/gerber/utils.py
index 533f0a2..f7df4ed 100644
--- a/gerbonara/gerber/utils.py
+++ b/gerbonara/gerber/utils.py
@@ -60,6 +60,13 @@ class LengthUnit:
         else:
             return id(self) == id(other)
 
+    # This class is a singleton, we don't want copies around
+    def __copy__(self):
+        return self
+
+    def __deepcopy__(self, memo):
+        return self
+
 
 MILLIMETERS_PER_INCH = 25.4
 Inch = LengthUnit('inch', 'in', MILLIMETERS_PER_INCH)