Reject oversized step-repeat expansions

Applies github PR #1. Thanks to @SaumyaShah08 on github!

src/gerbonara/aperture_macros/__init__.py

@@ -0,0 +1,18 @@
+
+from .parse import ApertureMacro, GenericMacros
+from .expression import (Expression,
+                        UnitExpression,
+                        ConstantExpression,
+                        VariableExpression,
+                        ParameterExpression,
+                        NegatedExpression,
+                        OperatorExpression)
+from .primitive import (Comment,
+                        Circle,
+                        VectorLine,
+                        CenterLine,
+                        Outline,
+                        Polygon,
+                        Moire,
+                        Thermal)
+

src/gerbonara/aperture_macros/expression.py

@@ -62,7 +62,7 @@ class Expression:
         return expr(other) / self
 
     def __neg__(self):
-        return NegatedExpression(self)
+        return NegatedExpression(self).optimized()
 
     def __pos__(self):
         return self
@@ -339,6 +339,12 @@ class OperatorExpression(Expression):
             # -x [*/] -y == x [*/] y
             case (NegatedExpression(l), (operator.truediv | operator.mul) as op, NegatedExpression(r)):
                 rv = op(l, r)
+            # -x [*/] y == -(x [*/] y)
+            case (NegatedExpression(l), (operator.truediv | operator.mul) as op, r):
+                rv = NegatedExpression(op(l, r))
+            # x [*/] -y == -(x [*/] y)
+            case (l, (operator.truediv | operator.mul) as op, NegatedExpression(r)):
+                rv = NegatedExpression(op(l, r))
             # x + -y == x - y
             case (l, operator.add, NegatedExpression(r)):
                 rv = l-r

src/gerbonara/aperture_macros/parse.py

@@ -3,7 +3,7 @@
 
 # Copyright 2021 Jan Sebastian Götte <gerbonara@jaseg.de>
 
-from dataclasses import dataclass, field, replace
+from dataclasses import dataclass, field, replace, fields
 import operator
 import re
 import ast
@@ -13,6 +13,7 @@ import math
 
 from . import primitive as ap
 from .expression import *
+from ..apertures import ApertureMacroInstance
 from ..utils import MM
 
 # we make our own here instead of using math.degrees to make sure this works with expressions, too.
@@ -57,10 +58,74 @@ def _parse_expression(expr, variables, parameters):
 
 @dataclass(frozen=True, slots=True)
 class ApertureMacro:
+    """ Definition of an aperture macro in a Gerber file.
+
+        An aperture macro is a collection of shape primitives that are flashed all at once. The properties of these
+        primitives such as their relative position and size can be given explicitly, or can be given as a basic
+        arithmetic expression (so +/-/*/:, no higher functions) based on parameters. After the macro is defined in the
+        Gerber file, it is *bound* to a particular set of parameter values in an aperture definition. One macro can be
+        used by zero, or by multiple aperture definitions. To flash a macro, you must first bind it in an aperture
+        definition, which can then be flash'ed.
+
+        Gerbonara calls these apertures that bind a macro :py:class:`~..apertures.ApertureMacroInst`. You can bind a
+        macro to a set of parameters by calling it:
+
+        .. code-block: python
+
+            # am is some instance of ApertureMacro
+            aperture_def = am(1, 2, 3)
+            gerber.objects.append(Flash(x=12, y=34, aperture=aperture_def))
+        
+        Internally, the aperture macro API uses millimeters though most functions allow you to pass an unit parameter.
+
+        When you want to programmatically create aperture macros, we recommend using :py:meth:`~.ApertureMacro.map` on a
+        dataclass-like class definition. Have a look at this code from :py:class:`~.GenericMacros`:
+
+        .. code-block: python
+
+            @ApertureMacro.map('GNR')
+            class rect:
+                w: float # width
+                h: float # height
+                hole_dia: float = 0
+                rotation: float = 0
+
+                def draw(self):
+                    yield ap.CenterLine('mm', 1, self.w, self.h, 0, 0, self.rotation * -deg_per_rad)
+                    yield ap.Circle('mm', 0, self.hole_dia, 0, 0)
+
+            # rect now is an instance of ApertureMacro
+
+        After this, you can bind this macro to an aperture by calling it. When you use this dataclass-like syntax,
+        keyword arguments are supported, and default values work like with normal dataclasses:
+            
+        .. code-block: python
+
+            # returns an instance of ApertureMacroInstance containing the given parameters
+            my_rect = GenericMacros.rect(w=12, h=34)
+
+            gerber.objects.append(Flash(x=12, y=34, aperture=my_rect))
+        
+        .. important::
+            Use your own programmatically defined aperture macros sparingly. While support is getting better, many
+            tools, including the expensive, commercial tools that PCB manufacturers use, still have bugs when handling
+            aperture macros. When using advanced macros with many primitives or with complex, embedded arithmetic
+            expressions, make sure to carefully check the manufacturing files provided by your PCB fab.
+
+            gerbonara currently handles embedded arithmetic expressions by *always* calculating them out since we have
+            recently seen high-end commercial tooling failing at issues as basic as operator precedence. This increases
+            file sizes very very slightly, but it makes sure that you get correct results.
+
+            This means that you can use gerbonara to calculate out aperture macros and hard-bake their values into the
+            gerber source. This can be useful if you have a file that includes complex macros that some manufacturer's
+            tooling can't handle on its own.
+            """
+
     name: str = field(default=None, hash=False, compare=False)
     num_parameters: int = 0
     primitives: tuple = ()
     comments: tuple = field(default=(), hash=False, compare=False)
+    _param_dataclass: object = field(default=None, hash=False, compare=False)
 
     def __post_init__(self):
         if self.name is None or re.match(r'GNX[0-9A-F]{16}', self.name):
@@ -70,6 +135,38 @@ class ApertureMacro:
     def _reset_name(self):
         object.__setattr__(self, 'name', f'GNX{hash(self)&0xffffffffffffffff:016X}')
 
+    @classmethod
+    def map(our_kls, macro_name=None):
+        def wrapper(kls):
+            nonlocal our_kls, macro_name
+            dc = dataclass(kls)
+            
+            # Construct a mock instance of the dataclass with every field bound to its correpsonding ParameterExpression,
+            # then draw() it to get a list of bound macro primitives.
+            primitives = tuple(dc(*[ParameterExpression(i+1) for i in range(len(fields(dc)))]).draw())
+            name = macro_name if macro_name else f'GNM{kls.__name__}'
+
+            # Python allows a lot more unicode in class names than the Gerber spec allows in aperture macro names
+            if not re.fullmatch('[._$a-zA-Z][._$a-zA-Z0-9]{0,126}', name):
+                raise ValueError(f'Name {name!r} is invalid as an aperture macro name')
+
+            return our_kls(
+                name = name,
+                num_parameters = len(fields(dc)),
+                primitives = primitives,
+                comments = [l.strip() for l in dc.__doc__.strip().splitlines()],
+                _param_dataclass = dc)
+        return wrapper
+
+    def __call__(self, *args, unit=MM, **kwargs):
+        if self._param_dataclass:
+            # Above, in map(), we construct the dataclass with the ParameterExpression(i) as params to draw the macro
+            # primitives. Here, we construct it with the user's supplied concrete numeric parameters instead, and then
+            # extract a list of these parameters. This should work great as long as the user doesn't get too fancy with
+            # dataclass metaprogramming hackery.
+            bound = self._param_dataclass(*args, **kwargs)
+            return ApertureMacroInstance(macro=self, parameters=tuple(getattr(bound, f.name) or 0 for f in fields(bound)), unit=unit)
+
     @classmethod
     def parse_macro(kls, macro_name, body, unit):
         comments = []
@@ -168,82 +265,191 @@ var = ParameterExpression
 deg_per_rad = 180 / math.pi
 
 class GenericMacros:
+    """NOTE:
+       All generic macros have rotation values specified in **clockwise radians** like the rest of the user-facing API.
+    """
 
-    _generic_hole = lambda n: (ap.Circle('mm', 0, var(n), 0, 0),)
+    @ApertureMacro.map('GNC')
+    class circle:
+        """ Filled circle macro with an optional round hole
+        
+        :param float diameter: Diameter of the circle
+        :param hole_dia: Diameter of the hole (optional)
+        """
+        diameter: float
+        hole_dia: float = 0
 
-    # NOTE: All generic macros have rotation values specified in **clockwise radians** like the rest of the user-facing
-    # API.
-    circle = ApertureMacro('GNC', 4, (
-        ap.Circle('mm', 1, var(1), 0, 0, var(4) * -deg_per_rad),
-        *_generic_hole(2)))
+        def draw(self):
+            yield ap.Circle('mm', 1, self.diameter, 0, 0)
+            yield ap.Circle('mm', 0, self.hole_dia, 0, 0)
 
-    rect = ApertureMacro('GNR', 5, (
-        ap.CenterLine('mm', 1, var(1), var(2), 0, 0, var(5) * -deg_per_rad),
-        *_generic_hole(3)))
+    @ApertureMacro.map('GNR')
+    class rect:
+        """ Axis-aligned rectangle with an optional round center hole.
 
-    # params: width, height, corner radius, *hole, rotation
-    rounded_rect = ApertureMacro('GRR', 6, (
-        ap.CenterLine('mm', 1, var(1)-2*var(3), var(2), 0, 0, var(6) * -deg_per_rad),
-        ap.CenterLine('mm', 1, var(1), var(2)-2*var(3), 0, 0, var(6) * -deg_per_rad),
-        ap.Circle('mm', 1, var(3)*2, +(var(1)/2-var(3)), +(var(2)/2-var(3)), var(6) * -deg_per_rad),
-        ap.Circle('mm', 1, var(3)*2, +(var(1)/2-var(3)), -(var(2)/2-var(3)), var(6) * -deg_per_rad),
-        ap.Circle('mm', 1, var(3)*2, -(var(1)/2-var(3)), +(var(2)/2-var(3)), var(6) * -deg_per_rad),
-        ap.Circle('mm', 1, var(3)*2, -(var(1)/2-var(3)), -(var(2)/2-var(3)), var(6) * -deg_per_rad),
-        *_generic_hole(4)))
+        :param float w: Width
+        :param float h: Height
+        :param float hole_dia: Diameter of the round hole (optional)
+        :param float rotation: Rotation in clockwise radians (optional)
+        """
+        w: float # width
+        h: float # height
+        hole_dia: float = 0
+        rotation: float = 0
 
-    # params: width, height, length difference between narrow side (top) and wide side (bottom), *hole, rotation
-    isosceles_trapezoid = ApertureMacro('GTR', 6, (
-        ap.Outline('mm', 1, 4,
-                          (var(1)/-2,            var(2)/-2,
-                          var(1)/-2+var(3)/2,   var(2)/2,
-                          var(1)/2-var(3)/2,    var(2)/2,
-                          var(1)/2,             var(2)/-2,
-                          var(1)/-2,            var(2)/-2,),
-                          var(6) * -deg_per_rad),
-        *_generic_hole(4)))
+        def draw(self):
+            yield ap.CenterLine('mm', 1, self.w, self.h, 0, 0, self.rotation * -deg_per_rad)
+            yield ap.Circle('mm', 0, self.hole_dia, 0, 0)
 
-    # params: width, height, length difference between narrow side (top) and wide side (bottom), margin, *hole, rotation
-    rounded_isosceles_trapezoid = ApertureMacro('GRTR', 7, (
-        ap.Outline('mm', 1, 4,
-                          (var(1)/-2,            var(2)/-2,
-                          var(1)/-2+var(3)/2,   var(2)/2,
-                          var(1)/2-var(3)/2,    var(2)/2,
-                          var(1)/2,             var(2)/-2,
-                          var(1)/-2,            var(2)/-2,),
-                          var(7) * -deg_per_rad),
-        ap.VectorLine('mm', 1, var(4)*2, 
-                          var(1)/-2,            var(2)/-2,
-                          var(1)/-2+var(3)/2,   var(2)/2,),
-        ap.VectorLine('mm', 1, var(4)*2, 
-                          var(1)/-2+var(3)/2,   var(2)/2,
-                          var(1)/2-var(3)/2,    var(2)/2,),
-        ap.VectorLine('mm', 1, var(4)*2, 
-                          var(1)/2-var(3)/2,    var(2)/2,
-                          var(1)/2,             var(2)/-2,),
-        ap.VectorLine('mm', 1, var(4)*2, 
-                          var(1)/2,             var(2)/-2,
-                          var(1)/-2,            var(2)/-2,),
-        ap.Circle('mm', 1, var(4)*2, 
-                          var(1)/-2,            var(2)/-2,),
-        ap.Circle('mm', 1, var(4)*2, 
-                          var(1)/-2+var(3)/2,   var(2)/2,),
-        ap.Circle('mm', 1, var(4)*2, 
-                          var(1)/2-var(3)/2,    var(2)/2,),
-        ap.Circle('mm', 1, var(4)*2, 
-                          var(1)/2,             var(2)/-2,),
-        *_generic_hole(5)))
+    @ApertureMacro.map('GRR')
+    class rounded_rect:
+        """ Rectangle with circular arc corners and an optional round center hole.
 
-    # w must be larger than h
-    # params: width, height, *hole, rotation
-    obround = ApertureMacro('GNO', 5, (
-        ap.CenterLine('mm', 1, var(1)-var(2), var(2), 0, 0, var(5) * -deg_per_rad),
-        ap.Circle('mm', 1, var(2), +(var(1)-var(2))/2, 0, var(5) * -deg_per_rad),
-        ap.Circle('mm', 1, var(2), -(var(1)-var(2))/2, 0, var(5) * -deg_per_rad),
-        *_generic_hole(3) ))
+        :param float w: Width
+        :param float h: Height
+        :param float r: Corner radius
+        :param float hole_dia: Diameter of the round hole (optional)
+        :param float rotation: Rotation in clockwise radians (optional)
+        """
+        w: float # width
+        h: float # height
+        r: float # Corner radius
+        hole_dia: float = 0
+        rotation: float = 0
 
-    polygon = ApertureMacro('GNP', 4, (
-        ap.Polygon('mm', 1, var(2), 0, 0, var(1), var(3) * -deg_per_rad),
-        ap.Circle('mm', 0, var(4), 0, 0)))
+        def draw(self):
+            yield ap.CenterLine('mm', 1, self.w-2*self.r, self.h, 0, 0, self.rotation * -deg_per_rad)
+            yield ap.CenterLine('mm', 1, self.w, self.h-2*self.r, 0, 0, self.rotation * -deg_per_rad)
+            yield ap.Circle('mm', 1, self.r*2, +(self.w/2-self.r), +(self.h/2-self.r), self.rotation * -deg_per_rad)
+            yield ap.Circle('mm', 1, self.r*2, +(self.w/2-self.r), -(self.h/2-self.r), self.rotation * -deg_per_rad)
+            yield ap.Circle('mm', 1, self.r*2, -(self.w/2-self.r), +(self.h/2-self.r), self.rotation * -deg_per_rad)
+            yield ap.Circle('mm', 1, self.r*2, -(self.w/2-self.r), -(self.h/2-self.r), self.rotation * -deg_per_rad)
+            yield ap.Circle('mm', 0, self.hole_dia, 0, 0)
+
+    @ApertureMacro.map('GTR')
+    class isosceles_trapezoid:
+        """ Isosceles trapezoid with a wider bottom edge and narrower top edge, with an optional round center hole.
+
+        :param float w: Width of the bottom (wider) edge
+        :param float h: Height
+        :param float d: Length difference between bottom and top edges; top width = w - d
+        :param float hole_dia: Diameter of the round hole (optional)
+        :param float rotation: Rotation in clockwise radians (optional)
+        """
+        w: float # width
+        h: float # height
+        d: float # length difference between narrow side (top) and wide side (bottom)
+        hole_dia: float = 0
+        rotation: float = 0
+        
+        def draw(self):
+            yield ap.Outline('mm', 1, 4,
+                          (self.w/-2,            self.h/-2,
+                          self.w/-2+self.d/2,   self.h/2,
+                          self.w/2-self.d/2,    self.h/2,
+                          self.w/2,             self.h/-2,
+                          self.w/-2,            self.h/-2,),
+                          self.rotation * -deg_per_rad)
+            yield ap.Circle('mm', 0, self.hole_dia, 0, 0)
+
+    @ApertureMacro.map('GRTR')
+    class rounded_isosceles_trapezoid:
+        """ Isosceles trapezoid with rounded corners and an optional round center hole. Unlike the rounded rectangle, the shape is defined by first defining a non-rounded trapezoid, which is then offet to the outside by the given margin.
+
+        :param float w: Width of the bottom (wider) edge
+        :param float h: Height
+        :param float d: Length difference between bottom and top edges; top width = w - d
+        :param float margin: Corner rounding radius
+        :param float hole_dia: Diameter of the round hole (optional)
+        :param float rotation: Rotation in clockwise radians (optional)
+        """
+        w: float
+        h: float
+        d: float # length difference between narrow side (top) and wide side (bottom)
+        margin: float
+        hole_dia: float = 0
+        rotation: float = 0
+
+        def draw(self):
+            rot = self.rotation * -deg_per_rad
+            yield ap.Outline('mm', 1, 4,
+                              (self.w/-2,            self.h/-2,
+                               self.w/-2+self.d/2,   self.h/2,
+                               self.w/2-self.d/2,    self.h/2,
+                               self.w/2,             self.h/-2,
+                               self.w/-2,            self.h/-2,),
+                             rot)
+
+            yield ap.VectorLine('mm', 1, self.margin*2, 
+                               self.w/-2,            self.h/-2,
+                               self.w/-2+self.d/2,   self.h/2,
+                               rot)
+            yield ap.VectorLine('mm', 1, self.margin*2, 
+                               self.w/-2+self.d/2,   self.h/2,
+                               self.w/2-self.d/2,    self.h/2,
+                               rot)
+            yield ap.VectorLine('mm', 1, self.margin*2, 
+                                self.w/2-self.d/2,    self.h/2,
+                                self.w/2,             self.h/-2,
+                                rot)
+            yield ap.VectorLine('mm', 1, self.margin*2,
+                                self.w/2,             self.h/-2,
+                                self.w/-2,            self.h/-2,
+                                rot)
+
+            yield ap.Circle('mm', 1, self.margin*2,
+                                self.w/-2,            self.h/-2,
+                            rot)
+            yield ap.Circle('mm', 1, self.margin*2, 
+                                self.w/-2+self.d/2,   self.h/2,
+                            rot)
+            yield ap.Circle('mm', 1, self.margin*2, 
+                                self.w/2-self.d/2,    self.h/2,
+                            rot)
+            yield ap.Circle('mm', 1, self.margin*2, 
+                                self.w/2,             self.h/-2,
+                            rot)
+
+            yield ap.Circle('mm', 0, self.hole_dia, 0, 0)
+
+    @ApertureMacro.map('GNO')
+    class obround:
+        """ Rectangle with semicircular end caps (stadium shape), with an optional round center hole. The long axis is along the X axis when rotation is zero.
+
+        :param float w: Total width including end caps; must satisfy w >= h
+        :param float h: Height, equal to the end cap diameter
+        :param float hole_dia: Diameter of the round hole (optional)
+        :param float rotation: Rotation in clockwise radians (optional)
+        """
+        w: float
+        h: float
+        hole_dia: float = 0
+        rotation: float = 0
+
+        def draw(self):
+            rot = self.rotation * -deg_per_rad
+            yield ap.CenterLine('mm', 1, self.w - self.h, self.h, 0, 0, rot)
+            yield ap.Circle('mm', 1, self.h, +(self.w-self.h)/2, 0, rot)
+            yield ap.Circle('mm', 1, self.h, -(self.w-self.h)/2, 0, rot)
+            yield ap.Circle('mm', 0, self.hole_dia, 0, 0)
+
+    @ApertureMacro.map('GNP')
+    class polygon:
+        """ Regular n-sided polygon with an optional round center hole.
+
+        :param int n: Number of sides
+        :param float diameter: Diameter of the circumscribed circle
+        :param float hole_dia: Diameter of the round hole (optional)
+        :param float rotation: Rotation in clockwise radians (optional)
+        """
+        n: int
+        diameter: float
+        hole_dia: float = 0
+        rotation: float = 0
+
+        def draw(self):
+            yield ap.Polygon('mm', 1, self.diameter, 0, 0, self.n, self.rotation * -deg_per_rad)
+            yield ap.Circle('mm', 0, self.hole_dia, 0, 0)
 
 
 if __name__ == '__main__':

src/gerbonara/aperture_macros/primitive.py

@@ -105,6 +105,10 @@ class Circle(Primitive):
         with self.Calculator(self, variable_binding, unit) as calc:
             x, y = rotate_point(calc.x, calc.y, -(deg_to_rad(calc.rotation) + rotation), 0, 0)
             x, y = x+offset[0], y+offset[1]
+
+            if math.isclose(calc.diameter, 0):
+                return []
+
             return [ gp.Circle(x, y, calc.diameter/2, polarity_dark=(bool(calc.exposure) == polarity_dark)) ]
 
     def substitute_params(self, binding, unit):
@@ -144,6 +148,9 @@ class VectorLine(Primitive):
             center_x, center_y = center_x+offset[0], center_y+offset[1]
             rotation += deg_to_rad(calc.rotation) + math.atan2(delta_y, delta_x)
 
+            if math.isclose(calc.width, 0):
+                return []
+
             return [ gp.Rectangle(center_x, center_y, length, calc.width, rotation=rotation,
                         polarity_dark=(bool(calc.exposure) == polarity_dark)) ]
 
@@ -182,6 +189,9 @@ class CenterLine(Primitive):
             x, y = x+offset[0], y+offset[1]
             w, h = calc.width, calc.height
 
+            if math.isclose(calc.width, 0) or math.isclose(calc.height, 0):
+                return []
+
             return [ gp.Rectangle(x, y, w, h, rotation, polarity_dark=(bool(calc.exposure) == polarity_dark)) ]
 
     def substitute_params(self, binding, unit):
@@ -217,7 +227,8 @@ class Polygon(Primitive):
             rotation += deg_to_rad(calc.rotation)
             x, y = rotate_point(calc.x, calc.y, -rotation, 0, 0)
             x, y = x+offset[0], y+offset[1]
-            return [ gp.ArcPoly.from_regular_polygon(calc.x, calc.y, calc.diameter/2, calc.n_vertices, rotation,
+            print('xy', calc.x, calc.y)
+            return [ gp.ArcPoly.from_regular_polygon(x, y, calc.diameter/2, int(calc.n_vertices), rotation,
                         polarity_dark=(bool(calc.exposure) == polarity_dark)) ]
 
     def dilated(self, offset, unit):
@@ -251,6 +262,9 @@ class Moire(Primitive):
             x, y = rotate_point(calc.x, calc.y, -rotation, 0, 0)
             x, y = x+offset[0], y+offset[1]
 
+            if math.isclose(calc.d_outer, 0):
+                return []
+
             pitch = calc.line_thickness + calc.gap_w
             for i in range(int(round(calc.num_circles))):
                 yield gp.Circle(x, y, calc.d_outer/2 - i*pitch, polarity_dark=True)
@@ -297,6 +311,9 @@ class Thermal(Primitive):
 
             dark = True
 
+            if math.isclose(calc.d_outer, 0):
+                return []
+
             return [
                     gp.Circle(x, y, calc.d_outer/2, polarity_dark=dark),
                     gp.Circle(x, y, calc.d_inner/2, polarity_dark=not dark),
@@ -383,6 +400,10 @@ class Outline(Primitive):
             bound_coords = [ rotate_point(calc(x), calc(y), -rotation, 0, 0) for x, y in self.points ]
             bound_coords = [ (x+offset[0], y+offset[1]) for x, y in bound_coords ]
             bound_radii = [None] * len(bound_coords)
+
+            if len(bound_coords) < 3:
+                return []
+
             return [gp.ArcPoly(bound_coords, bound_radii, polarity_dark=(bool(calc.exposure) == polarity_dark))]
 
     def dilated(self, offset, unit):

src/gerbonara/apertures.py

@@ -21,7 +21,6 @@ import math
 from dataclasses import dataclass, replace, field, fields, InitVar, KW_ONLY
 from functools import lru_cache
 
-from .aperture_macros.parse import GenericMacros
 from .utils import LengthUnit, MM, Inch, sum_bounds
 
 from . import graphic_primitives as gp
@@ -160,7 +159,8 @@ class ExcellonTool(Aperture):
         return self
 
     def to_macro(self, rotation=0):
-        return ApertureMacroInstance(GenericMacros.circle, self._params(unit=MM))
+        from .aperture_macros.parse import GenericMacros
+        return ApertureMacroInstance(GenericMacros.circle, self._params(unit=MM), unit=MM)
 
     def _params(self, unit=None):
         return (self.unit.convert_to(unit, self.diameter),)
@@ -205,7 +205,9 @@ class CircleAperture(Aperture):
                        hole_dia=None if self.hole_dia is None else self.hole_dia*scale)
 
     def to_macro(self, rotation=0):
-        return ApertureMacroInstance(GenericMacros.circle, self._params(unit=MM))
+        from .aperture_macros.parse import GenericMacros
+        return GenericMacros.circle(MM(self.diameter, self.unit),
+                                    MM(self.hole_dia, self.unit))
 
     def _params(self, unit=None):
         return _strip_right(
@@ -260,12 +262,11 @@ class RectangleAperture(Aperture):
                        hole_dia=None if self.hole_dia is None else self.hole_dia*scale)
 
     def to_macro(self, rotation=0):
-        return ApertureMacroInstance(GenericMacros.rect,
-                (MM(self.w, self.unit),
-                    MM(self.h, self.unit),
-                    MM(self.hole_dia, self.unit) or 0,
-                    0,
-                    rotation))
+        from .aperture_macros.parse import GenericMacros
+        return GenericMacros.rect(MM(self.w, self.unit),
+                                  MM(self.h, self.unit),
+                                  MM(self.hole_dia, self.unit),
+                                  rotation)
 
     def _params(self, unit=None):
         return _strip_right(
@@ -329,12 +330,11 @@ class ObroundAperture(Aperture):
             rotation -= -math.pi/2
             inst = replace(self, w=self.h, h=self.w, hole_dia=self.hole_dia)
 
-        return ApertureMacroInstance(GenericMacros.obround,
-                (MM(inst.w, self.unit),
-                 MM(inst.h, self.unit),
-                 MM(inst.hole_dia, self.unit) or 0,
-                 0,
-                 rotation))
+        from .aperture_macros.parse import GenericMacros
+        return GenericMacros.obround(MM(inst.w, self.unit),
+                                     MM(inst.h, self.unit),
+                                     MM(inst.hole_dia, self.unit) or 0,
+                                     rotation)
 
     def _params(self, unit=None):
         return _strip_right(
@@ -390,7 +390,11 @@ class PolygonAperture(Aperture):
                        hole_dia=None if self.hole_dia is None else self.hole_dia*scale)
 
     def to_macro(self):
-        return ApertureMacroInstance(GenericMacros.polygon, self._params(MM))
+        from .aperture_macros.parse import GenericMacros
+        return GenericMacros.polygon(self.n_vertices,
+                                     MM(self.diameter, self.unit),
+                                     MM(self.hole_dia, self.unit),
+                                     self.rotation)
 
     def _params(self, unit=None):
         rotation = self.rotation % (2*math.pi / self.n_vertices)

src/gerbonara/cad/kicad/footprints.py

@@ -423,11 +423,11 @@ class Pad(NetMixin):
 
         elif self.shape == Atom.rect:
             if margin > 0:
-                return ap.ApertureMacroInstance(GenericMacros.rounded_rect,
-                        (self.size.x+2*margin, self.size.y+2*margin,
-                         margin,
-                         0, 0, # no hole
-                         rotation), unit=MM)
+                return GenericMacros.rounded_rect(self.size.x+2*margin,
+                                                  self.size.y+2*margin,
+                                                  margin,
+                                                  0, # no hole
+                                                  rotation)
             else:
                 return ap.RectangleAperture(self.size.x+2*margin, self.size.y+2*margin, unit=MM).rotated(-rotation)
 
@@ -454,28 +454,29 @@ class Pad(NetMixin):
                 # Note: KiCad already uses MM units, so no conversion needed here.
 
                 alpha = math.atan(y / dy) if dy > 0 else 0
-                return ap.ApertureMacroInstance(GenericMacros.isosceles_trapezoid,
-                        (x+dy+2*margin*math.cos(alpha), y+2*margin,
-                         2*dy,
-                         0, 0, # no hole
-                         -rotation + math.pi), unit=MM)
+                return GenericMacros.isosceles_trapezoid(x+dy+2*margin*math.cos(alpha),
+                                                         y+2*margin,
+                                                         2*dy,
+                                                         0, # no hole
+                                                         -rotation + math.pi)
 
             else:
-                return ap.ApertureMacroInstance(GenericMacros.rounded_isosceles_trapezoid,
-                        (x+dy, y,
-                         2*dy, margin,
-                         0, 0, # no hole
-                         -rotation + math.pi), unit=MM)
+                return GenericMacros.rounded_isosceles_trapezoid(x+dy,
+                                                                 y,
+                                                                 2*dy,
+                                                                 margin,
+                                                                 0, # no hole
+                                                                 -rotation + math.pi)
 
         elif self.shape == Atom.roundrect:
             x, y = self.size.x, self.size.y
             r = min(x, y) * self.roundrect_rratio
             if margin > -r:
-                return ap.ApertureMacroInstance(GenericMacros.rounded_rect,
-                        (x+2*margin, y+2*margin,
-                         r+margin,
-                         0, 0, # no hole
-                         rotation), unit=MM)
+                return GenericMacros.rounded_rect(x+2*margin,
+                                                  y+2*margin,
+                                                  r+margin,
+                                                  0, # no hole
+                                                  rotation)
             else:
                 return ap.RectangleAperture(x+margin, y+margin, unit=MM).rotated(-rotation)
 

src/gerbonara/excellon.py

@@ -890,12 +890,17 @@ class ExcellonParser(object):
                 # from https://math.stackexchange.com/a/1781546
                 if a_s:
                     raise ValueError('Negative arc radius given')
-                r = settings.parse_gerber_value(a)
+                r = self.settings.parse_gerber_value(a)
                 x1, y1 = start
                 x2, y2 = end
                 dx, dy = (x2-x1)/2, (y2-y1)/2
                 x0, y0 = x1+dx, y1+dy
-                f = math.hypot(dx, dy) / math.sqrt(r**2 - a**2)
+                d = math.hypot(dx, dy)
+                if d == 0:
+                    raise ValueError('Arc radius notation requires distinct start and end points')
+                if r < d:
+                    raise ValueError('Arc radius too small for endpoint distance')
+                f = math.sqrt(r**2 - d**2) / d
                 if clockwise:
                     cx = x0 + f*dy
                     cy = y0 - f*dx
@@ -905,16 +910,16 @@ class ExcellonParser(object):
                 i, j = cx-start[0], cy-start[1]
 
             else: # explicit center given
-                i = settings.parse_gerber_value(i)
+                i = self.settings.parse_gerber_value(i) or 0
                 if i_s:
                     i = -i
-                j = settings.parse_gerber_value(j)
+                j = self.settings.parse_gerber_value(j) or 0
                 if j_s:
-                    j = -i
+                    j = -j
 
-            self.objects.append(Arc(*start, *end, i, j, True, self.active_tool, unit=self.settings.unit))
+            self.objects.append(Arc(*start, *end, i, j, clockwise, self.active_tool, unit=self.settings.unit))
 
-    @exprs.match(r'(M71|METRIC|M72|INCH)(,LZ|,TZ)?(,0*\.0*)?')
+    @exprs.match(r'(M71|METRIC|M72|INCH)(,LZ|,TZ)?(,([0-9]+\.[0-9]+|0*\.0*))?')
     def parse_easyeda_format(self, match):
         metric = match[1] in ('METRIC', 'M71')
 
@@ -927,7 +932,10 @@ class ExcellonParser(object):
         # This is used by newer autodesk eagles, fritzing and diptrace
         if match[3]:
             integer, _, fractional = match[3][1:].partition('.')
-            self.settings.number_format = len(integer), len(fractional)
+            if integer.strip('0') or fractional.strip('0'):
+                self.settings.number_format = int(integer), int(fractional)
+            else:
+                self.settings.number_format = len(integer), len(fractional)
 
         elif self.settings.number_format == (None, None) and not metric and not self.found_kicad_format_comment:
             self.warn('Using implicit number format from bare "INCH" statement. This is normal for Fritzing, Diptrace, Geda and pcb-rnd.')
@@ -953,10 +961,10 @@ class ExcellonParser(object):
     @exprs.match('(FMAT|VER),?([0-9]*)')
     def handle_command_format(self, match):
         if match[1] == 'FMAT':
-            # We do not support integer/fractional decimals specification via FMAT because that's stupid. If you need this,
-            # please raise an issue on our issue tracker, provide a sample file and tell us where on earth you found that
-            # file.
-            if match[2] not in ('', '2'):
+            # We only use FMAT as a compatibility marker. Version 1 drill files encountered in the wild still use the
+            # same coordinate and routing statements that we already support, so rejecting the header unconditionally
+            # needlessly breaks otherwise parseable files.
+            if match[2] not in ('', '1', '2'):
                 raise SyntaxError(f'Unsupported FMAT format version {match[2]}')
 
         else: # VER
@@ -985,6 +993,19 @@ class ExcellonParser(object):
         else:
             self.warn('Bare coordinate after end of file')
 
+    @exprs.match(xy_coord + 'G85' + xy_coord)
+    def handle_g85_slot(self, match):
+        if self.program_state == ProgramState.HEADER:
+            return
+
+        self.do_move(match.groups()[:4])
+        start, end = self.do_move(match.groups()[4:])
+
+        if not self.ensure_active_tool():
+            return
+
+        self.objects.append(Line(*start, *end, self.active_tool, unit=self.settings.unit))
+
     @exprs.match(r'DETECT,ON|ATC,ON|M06')
     def parse_zuken_legacy_statements(self, match):
         self.generator_hints.append('zuken')

src/gerbonara/rs274x.py

@@ -599,6 +599,8 @@ class GerberParser:
     NUMBER = r"[\+-]?\d+"
     DECIMAL = r"[\+-]?\d+([.]?\d+)?"
     NAME = r"[a-zA-Z_$\.][a-zA-Z_$\.0-9+\-]+"
+    MAX_STEP_REPEAT_INSTANCES = 100000
+    MAX_STEP_REPEAT_RESULT_OBJECTS = 100000
 
     STATEMENT_REGEXES = {
         'coord': fr"(G0?[123]|G74|G75|G54|G55)?\s*(?:X\+?(-?)({NUMBER}))?(?:Y\+?(-?)({NUMBER}))?" \
@@ -1081,7 +1083,7 @@ class GerberParser:
 
         else:
             target = {'TF': self.file_attrs, 'TO': self.graphics_state.object_attrs, 'TA': self.aperture_attrs}[match['type']]
-            target[match['name']] = tuple(match['value'].split(','))
+            target[match['name']] = tuple(match['value'].split(',')) if match['value'] else ()
 
             if 'EAGLE' in self.file_attrs.get('.GenerationSoftware', []) or match['eagle_garbage']:
                 self.generator_hints.append('eagle')
@@ -1095,18 +1097,23 @@ class GerberParser:
             i, j = float(match['I']), float(match['J'])
             if x < 1 or y < 1:
                 raise SyntaxError('SR step-repeat X and Y values must be at least 1')
+            if x * y > self.MAX_STEP_REPEAT_INSTANCES:
+                raise SyntaxError('SR step-repeat expands to too many instances')
 
-            self.step_repeat_coords = [
-                    (i*nx, j*ny)
-                    for nx in range(x) for ny in range(y)] # the order matters here, cf. the spec
+            self.step_repeat_coords = (x, y, i, j)
             self.step_repeat_objects = []
 
         else:
+            x, y, i, j = self.step_repeat_coords
+            if len(self.step_repeat_objects) * x * y > self.MAX_STEP_REPEAT_RESULT_OBJECTS:
+                raise SyntaxError('SR step-repeat expands to too many objects')
+
             for obj in self.step_repeat_objects:
-                for dx, dy in self.step_repeat_coords: 
-                    new_obj = copy.copy(obj)
-                    new_obj.offset(dx, dy)
-                    self.target.objects.append(new_obj)
+                for nx in range(x):
+                    for ny in range(y):
+                        new_obj = copy.copy(obj)
+                        new_obj.offset(i * nx, j * ny)
+                        self.target.objects.append(new_obj)
             self.step_repeat_coords = None
             self.step_repeat_objects = None
 

tests/test_aperture_macro.py

@@ -0,0 +1,774 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+#
+# Copyright 2026 Jan Sebastian Götte <gerbonara@jaseg.de>
+#
+# 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.
+#
+# Based on https://github.com/tracespace/tracespace
+#
+
+import math
+import operator as op
+from contextlib import contextmanager
+
+from PIL import Image
+import pytest
+
+from gerbonara.rs274x import GerberFile
+from gerbonara.graphic_objects import Line, Arc, Flash, Region
+from gerbonara.apertures import *
+from gerbonara import aperture_macros as am
+from gerbonara.aperture_macros import (
+    ConstantExpression, ParameterExpression, OperatorExpression,
+    NegatedExpression, VariableExpression, UnitExpression,
+)
+from gerbonara.aperture_macros.expression import expr
+from gerbonara.aperture_macros.parse import _parse_expression
+from gerbonara.cam import FileSettings
+from gerbonara.utils import MM, Inch, MILLIMETERS_PER_INCH
+
+from .image_support import svg_soup
+from .utils import *
+
+# Short aliases used throughout expression tests
+C = ConstantExpression
+P = ParameterExpression
+
+
+@contextmanager
+def run_aperture_macro_test(tmpfile, img_support, inst: ApertureMacroInstance, epsilon=1e-3):
+    gbr = GerberFile()
+
+    inst_rot_90 = inst.rotated(math.pi/2)
+    inst_rot_45 = inst.rotated(math.pi/4)
+    inst_rot_neg90 = inst.rotated(-math.pi/2)
+    for x, y in [(0, 0), (0, 10), (10, 0), (10, 10)]:
+        gbr.objects.append(Flash(x=x, y=y, aperture=inst, unit=MM))
+        gbr.objects.append(Flash(x=x, y=20+y, aperture=inst_rot_90, unit=MM))
+        gbr.objects.append(Flash(x=20+x, y=y, aperture=inst_rot_neg90, unit=MM))
+        gbr.objects.append(Flash(x=20+x, y=20+y, aperture=inst_rot_45, unit=MM))
+
+    # inches, to pixel align our SVG output with gerbv's!
+    bounds = (-.5, -.5), (2.0, 2.0) # bottom left, top right
+
+    # The below code is mostly copy-pasted from test_rs274x.py.
+
+    out_svg = tmpfile('SVG Output', '.svg')
+    with open(out_svg, 'w') as f:
+        # Use inch units here to make sure we and gerbv agree on the exact pixel size of the output since both calculate
+        # it from the DPI setting.
+        f.write(str(gbr.to_svg(force_bounds=bounds, arg_unit='inch', fg='black', bg='white')))
+
+    # Reference export via gerber through GerbV
+    out_gbr = tmpfile('GBR Output', '.gbr')
+    gbr.save(out_gbr)
+
+    # NOTE: Instead of having gerbv directly export a PNG, we ask gerbv to output SVG which we then rasterize using
+    # resvg. We have to do this since gerbv's built-in cairo-based PNG export has severe aliasing issues. In contrast,
+    # using resvg for both allows an apples-to-apples comparison of both results.
+    ref_svg = tmpfile('Reference export', '.svg')
+    w, h = bounds[1][0] - bounds[0][0], bounds[1][1] - bounds[0][1]
+    img_support.gerbv_export(out_gbr, ref_svg, origin=bounds[0], size=(w, h), fg='#000000', bg='#ffffff')
+    with svg_soup(ref_svg) as soup:
+        img_support.cleanup_gerbv_svg(soup)
+
+    ref_png = tmpfile('Reference render', '.png')
+    img_support.svg_to_png(ref_svg, ref_png, dpi=300, bg='white')
+
+    out_png = tmpfile('Output render', '.png')
+    img_support.svg_to_png(out_svg, out_png, dpi=300, bg='white')
+
+    mean, _max, hist = img_support.image_difference(ref_png, out_png, diff_out=tmpfile('Difference', '.png'))
+    assert hist[9] < 1
+    assert mean < epsilon
+    assert hist[3:].sum() < epsilon*hist.size
+
+
+@pytest.mark.parametrize('aperture_type', [
+    lambda: CircleAperture(4.0, unit=MM),
+    lambda: CircleAperture(4.0, hole_dia=1.5, unit=MM),
+    lambda: RectangleAperture(4.0, 3.0, unit=MM),
+    lambda: ObroundAperture(4.0, 2.5, unit=MM),
+    lambda: PolygonAperture(4.0, 6, unit=MM),
+])
+def test_macro_conversions(tmpfile, img_support, aperture_type):
+    ap = aperture_type()
+    inst = ap.to_macro()
+    run_aperture_macro_test(tmpfile, img_support, inst)
+
+
+@pytest.mark.parametrize('params', [(10, 0), (7, 0), (10, 5)])
+def test_generic_macro_circle(tmpfile, img_support, params):
+    ap = am.GenericMacros.circle(*params)
+    # epsilon changed since gerbv approximates circles with cubic splines which ends up pretty wrong at this scale
+    run_aperture_macro_test(tmpfile, img_support, ap, epsilon=1e-2)
+
+@pytest.mark.parametrize('params', [
+    (10, 10, 0, 0),
+    (10,  5, 0, 0),
+    ( 5, 10, 0, 0),
+    (10, 10, 5, 0),
+    (10,  7, 3, 0),
+    (10, 10, 0, math.pi/2),
+    (10, 10, 0, math.pi/3),
+    (10,  5, 0, math.pi/3),
+    ( 7, 10, 3, math.pi/3)])
+def test_generic_macro_rect(tmpfile, img_support, params):
+    ap = am.GenericMacros.rect(*params)
+    run_aperture_macro_test(tmpfile, img_support, ap, epsilon=1e-2)
+
+@pytest.mark.parametrize('params', [
+    (10, 10, 0, 0, 0),
+    (10,  5, 0, 0, 0),
+    ( 5, 10, 0, 0, 0),
+    (10, 10, 0, 5, 0),
+    (10,  7, 0, 3, 0),
+    (10, 10, 0, 0, math.pi/2),
+    (10, 10, 0, 0, math.pi/3),
+    (10,  5, 0, 0, math.pi/3),
+    ( 7, 10, 0, 3, math.pi/3),
+    (10, 10, 2, 0, 0),
+    (10,  5, 2, 0, 0),
+    ( 5, 10, 2, 0, 0),
+    (10, 10, 2, 5, 0),
+    (10,  7, 2, 3, 0),
+    (10, 10, 2, 0, math.pi/2),
+    (10, 10, 2, 0, math.pi/3),
+    (10,  5, 2, 0, math.pi/3),
+    ( 7, 10, 2, 3, math.pi/3),
+    ])
+def test_generic_macro_rounded_rect(tmpfile, img_support, params):
+    ap = am.GenericMacros.rounded_rect(*params)
+    run_aperture_macro_test(tmpfile, img_support, ap, epsilon=1e-2)
+
+@pytest.mark.parametrize('params', [
+    (10,  8, 2, 0, 0),
+    (10,  8, 4, 0, 0),
+    ( 8, 10, 2, 0, 0),
+    (10,  8, 2, 3, 0),
+    (10,  8, 2, 0, math.pi/2),
+    (10,  8, 2, 0, math.pi/3),
+    (10,  8, 2, 3, math.pi/3),
+    (10,  8, 0, 0, 0), # d=0: degenerate case (rectangle)
+    ])
+def test_generic_macro_isosceles_trapezoid(tmpfile, img_support, params):
+    ap = am.GenericMacros.isosceles_trapezoid(*params)
+    run_aperture_macro_test(tmpfile, img_support, ap)
+
+@pytest.mark.parametrize('params', [
+    # (w, h, d, margin, hole_dia, rotation)
+    (10, 8, 2, 1, 0, 0),
+    (10, 8, 4, 1, 0, 0),
+    (10, 8, 2, 1, 3, 0),
+    (10, 8, 2, 1, 0, math.pi/2),
+    (10, 8, 2, 1, 0, math.pi/3),
+    (10, 8, 2, 1, 3, math.pi/3),
+    ])
+def test_generic_macro_rounded_isosceles_trapezoid(tmpfile, img_support, params):
+    ap = am.GenericMacros.rounded_isosceles_trapezoid(*params)
+    run_aperture_macro_test(tmpfile, img_support, ap)
+
+@pytest.mark.parametrize('params', [
+    # (w, h, hole_dia, rotation), w >= h required
+    (10, 5, 0, 0),
+    ( 8, 4, 0, 0),
+    (10, 5, 2, 0),
+    ( 7, 7, 0, 0), # w == h: circle
+    (10, 5, 0, math.pi/2),
+    (10, 5, 0, math.pi/3),
+    (10, 5, 2, math.pi/3),
+    ])
+def test_generic_macro_obround(tmpfile, img_support, params):
+    ap = am.GenericMacros.obround(*params)
+    run_aperture_macro_test(tmpfile, img_support, ap, epsilon=1e-2)
+
+@pytest.mark.parametrize('params', [
+    # (n, diameter, hole_dia, rotation)
+    (3, 10, 0, 0),
+    (4, 10, 0, 0),
+    (5, 10, 0, 0),
+    (6, 10, 0, 0),
+    (6, 10, 3, 0),
+    (6, 10, 0, math.pi/6),
+    (5, 10, 0, math.pi/4),
+    (5, 10, 3, math.pi/4),
+    (3, 10, 3, math.pi/3),
+    ])
+def test_generic_macro_polygon(tmpfile, img_support, params):
+    ap = am.GenericMacros.polygon(*params)
+    run_aperture_macro_test(tmpfile, img_support, ap)
+
+@pytest.mark.parametrize('abc', [(2.0, 1.6, 2.3), (2.2, 1.6, 2.3), (2.1, 1.7, 2.4)])
+def test_macro_formulas(tmpfile, img_support, abc):
+    @am.ApertureMacro.map()
+    class test_macro:
+        a: float
+        b: float
+        c: float
+        
+        def draw(self):
+            d = 1.3
+            yield am.Circle('mm', 0, d, 0, 0)
+            yield am.Circle('mm', 0, d, 2, 0)
+            yield am.Circle('mm', 0, d, 4, 0)
+            yield am.Circle('mm', 0, d, 2, self.a)
+            yield am.Circle('mm', 0, d, 2, self.a+self.b)
+            yield am.Circle('mm', 0, d, 2, self.a+self.b+self.c)
+            yield am.Circle('mm', 0, d, 4, self.a * 1.1)
+            yield am.Circle('mm', 0, d, 4, self.b * 1.9)
+            yield am.Circle('mm', 0, d, 4, self.c * 2.2)
+            yield am.Circle('mm', 0, d, 6, 2 * self.a / self.b)
+            yield am.Circle('mm', 0, d, 6, 4 * self.b / self.c)
+            yield am.Circle('mm', 0, d, 6, 6 * self.c / self.a)
+            yield am.Circle('mm', 0, d, 8, self.a - self.b * self.a / self.c)
+            yield am.Circle('mm', 0, d, 8, 2 + self.a - self.b * self.a / self.c)
+            yield am.Circle('mm', 0, d, 8, self.a - 2 * self.b * self.a / self.c)
+    
+    inst = test_macro(*abc)
+    run_aperture_macro_test(tmpfile, img_support, inst)
+
+
+# =============================================================================
+# Expression language unit tests
+# =============================================================================
+
+class TestConstantExpression:
+    def test_value_stored(self):
+        assert C(5).value == 5
+
+    def test_float_conversion(self):
+        assert float(C(3.14)) == pytest.approx(3.14)
+
+    def test_calculate_no_binding(self):
+        assert C(42.0).calculate() == pytest.approx(42.0)
+
+    def test_calculate_ignores_binding(self):
+        assert C(7.0).calculate({1: 99.0}) == pytest.approx(7.0)
+
+    def test_to_gerber_integer(self):
+        assert C(5).to_gerber() == '5'
+
+    def test_to_gerber_float(self):
+        assert C(1.5).to_gerber() == '1.5'
+
+    def test_to_gerber_trailing_zeros_stripped(self):
+        assert C(1.500000).to_gerber() == '1.5'
+        assert C(2.0).to_gerber() == '2'
+
+    def test_to_gerber_zero(self):
+        assert C(0).to_gerber() == '0'
+
+    def test_to_gerber_negative_zero_avoided(self):
+        # -0.0 must not serialize as '-0'
+        assert C(-0.0).to_gerber() == '0'
+
+    def test_equality_exact(self):
+        assert C(3.0) == C(3.0)
+
+    def test_equality_within_tolerance(self):
+        assert C(1.0) == C(1.0 + 1e-10)
+
+    def test_inequality_outside_tolerance(self):
+        assert not (C(1.0) == C(2.0))
+
+    def test_equality_with_plain_number(self):
+        assert C(0) == 0
+        assert C(1) == 1
+        assert C(-1) == -1
+
+    def test_parameters_empty(self):
+        assert list(C(5).parameters()) == []
+
+
+class TestParameterExpression:
+    def test_to_gerber(self):
+        assert P(1).to_gerber() == '$1'
+        assert P(3).to_gerber() == '$3'
+        assert P(42).to_gerber() == '$42'
+
+    def test_calculate_with_binding(self):
+        assert P(1).calculate({1: 5.0}) == pytest.approx(5.0)
+        assert P(2).calculate({1: 10.0, 2: 20.0}) == pytest.approx(20.0)
+
+    def test_calculate_unresolved_raises(self):
+        with pytest.raises(IndexError):
+            P(1).calculate({})
+
+    def test_calculate_missing_param_raises(self):
+        with pytest.raises(IndexError):
+            P(2).calculate({1: 5.0})
+
+    def test_parameters_yields_self(self):
+        p = P(1)
+        assert list(p.parameters()) == [p]
+
+    def test_optimized_with_binding_resolves(self):
+        assert P(1).optimized({1: 7.5}) == C(7.5)
+
+    def test_optimized_without_binding_is_identity(self):
+        p = P(1)
+        assert p.optimized({}) is p
+
+
+class TestArithmeticOperators:
+    @pytest.mark.parametrize('a,b', [(3.0, 7.0), (-1.5, 4.2), (0.5, 0.25), (0.0, 5.0)])
+    def test_add(self, a, b):
+        assert (P(1) + P(2)).calculate({1: a, 2: b}) == pytest.approx(a + b)
+
+    @pytest.mark.parametrize('a,b', [(3.0, 7.0), (-1.5, 4.2), (0.5, 0.25), (5.0, 5.0)])
+    def test_sub(self, a, b):
+        assert (P(1) - P(2)).calculate({1: a, 2: b}) == pytest.approx(a - b)
+
+    @pytest.mark.parametrize('a,b', [(3.0, 7.0), (-1.5, 4.2), (0.5, 0.25), (0.0, 5.0)])
+    def test_mul(self, a, b):
+        assert (P(1) * P(2)).calculate({1: a, 2: b}) == pytest.approx(a * b)
+
+    @pytest.mark.parametrize('a,b', [(6.0, 3.0), (-4.5, 1.5), (1.0, 4.0)])
+    def test_div(self, a, b):
+        assert (P(1) / P(2)).calculate({1: a, 2: b}) == pytest.approx(a / b)
+
+    def test_radd(self):
+        assert (5.0 + P(1)).calculate({1: 3.0}) == pytest.approx(8.0)
+
+    def test_rsub(self):
+        assert (10.0 - P(1)).calculate({1: 3.0}) == pytest.approx(7.0)
+
+    def test_rmul(self):
+        assert (2.0 * P(1)).calculate({1: 4.0}) == pytest.approx(8.0)
+
+    def test_rdiv(self):
+        assert (10.0 / P(1)).calculate({1: 2.0}) == pytest.approx(5.0)
+
+    def test_neg(self):
+        assert (-P(1)).calculate({1: 5.0}) == pytest.approx(-5.0)
+
+    def test_pos_is_identity(self):
+        p = P(1)
+        assert +p is p
+
+
+# Cross-check expression evaluation against Python's own arithmetic.
+# A single lambda serves both roles: called with P() objects it builds an expression tree;
+# called with plain numbers it computes the Python reference value (ints/floats auto-convert).
+@pytest.mark.parametrize('f,binding', [
+    (lambda p1, p2, p3: p1 + p2,            {1: 3,  2: 7,  3: 0}),
+    (lambda p1, p2, p3: p1 - p2,            {1: 10, 2: 3,  3: 0}),
+    (lambda p1, p2, p3: p1 * p2,            {1: 3,  2: 4,  3: 0}),
+    (lambda p1, p2, p3: p1 / p2,            {1: 9,  2: 3,  3: 0}),
+    (lambda p1, p2, p3: p1 + p2 + p3,       {1: 1,  2: 2,  3: 3}),
+    (lambda p1, p2, p3: p1 * p2 + p3,       {1: 2,  2: 3,  3: 4}),
+    (lambda p1, p2, p3: p1 + p2 * p3,       {1: 2,  2: 3,  3: 4}),
+    (lambda p1, p2, p3: (p1 + p2) * p3,     {1: 2,  2: 3,  3: 4}),
+    (lambda p1, p2, p3: p1 / p2 + p3,       {1: 6,  2: 3,  3: 1}),
+    (lambda p1, p2, p3: p1 - p2 * p3,       {1: 10, 2: 2,  3: 3}),
+    (lambda p1, p2, p3: (p1 + p2) / p3,     {1: 3,  2: 5,  3: 4}),
+    (lambda p1, p2, p3: p1 * (p2 - p3),     {1: 3,  2: 7,  3: 2}),
+    (lambda p1, p2, p3: p1 * 2 + 3,         {1: 5,  2: 0,  3: 0}),
+    (lambda p1, p2, p3: 10 - p1 * p2,       {1: 2,  2: 3,  3: 0}),
+    (lambda p1, p2, p3: p1 / 2 + p2,        {1: 6,  2: 1,  3: 0}),
+    (lambda p1, p2, p3: -p1 + p2,           {1: 3,  2: 7,  3: 0}),
+    (lambda p1, p2, p3: p1 + (-p2),         {1: 10, 2: 3,  3: 0}),
+    (lambda p1, p2, p3: p1 * (-p2),         {1: 3,  2: 4,  3: 0}),
+    (lambda p1, p2, p3: (-p1) * (-p2),      {1: 3,  2: 4,  3: 0}),
+    (lambda p1, p2, p3: (-p1) / (-p2),      {1: 6,  2: 3,  3: 0}),
+    (lambda p1, p2, p3: p1 - (-p2),         {1: 5,  2: 3,  3: 0}),
+    (lambda p1, p2, p3: (p1+p2) * (p1-p3),  {1: 5,  2: 3,  3: 2}),
+    (lambda p1, p2, p3: p1 / p2 * p3,       {1: 6,  2: 2,  3: 5}),
+])
+def test_expression_against_python(f, binding):
+    """Build a gerbonara expression and compare its result to Python's evaluation."""
+    a, b, c = binding.get(1, 0), binding.get(2, 0), binding.get(3, 0)
+    assert f(P(1), P(2), P(3)).calculate(binding) == pytest.approx(f(a, b, c), rel=1e-9, abs=1e-12)
+
+
+class TestConstantFolding:
+    """Operations on two ConstantExpressions must immediately produce a ConstantExpression."""
+
+    def test_add(self):
+        result = C(3) + C(4)
+        assert isinstance(result, ConstantExpression) and result.value == pytest.approx(7)
+
+    def test_sub(self):
+        result = C(10) - C(4)
+        assert isinstance(result, ConstantExpression) and result.value == pytest.approx(6)
+
+    def test_mul(self):
+        result = C(3) * C(4)
+        assert isinstance(result, ConstantExpression) and result.value == pytest.approx(12)
+
+    def test_div(self):
+        result = C(10) / C(4)
+        assert isinstance(result, ConstantExpression) and result.value == pytest.approx(2.5)
+
+    def test_neg_of_constant(self):
+        result = -C(5)
+        assert isinstance(result, ConstantExpression) and result.value == pytest.approx(-5)
+
+    def test_nested(self):
+        result = (C(3) + C(4)) * C(2)
+        assert isinstance(result, ConstantExpression) and result.value == pytest.approx(14)
+
+    def test_deeply_nested(self):
+        result = C(2) * C(3) + C(4) * C(5)
+        assert isinstance(result, ConstantExpression) and result.value == pytest.approx(26)
+
+
+class TestAlgebraicOptimizations:
+    """Each algebraic simplification rule in OperatorExpression.optimized()."""
+
+    def test_zero_plus_x(self):
+        assert C(0) + P(1) == P(1)
+
+    def test_x_plus_zero(self):
+        assert P(1) + C(0) == P(1)
+
+    def test_zero_times_x(self):
+        assert C(0) * P(1) == C(0)
+
+    def test_x_times_zero(self):
+        assert P(1) * C(0) == C(0)
+
+    def test_one_times_x(self):
+        assert C(1) * P(1) == P(1)
+
+    def test_x_times_one(self):
+        assert P(1) * C(1) == P(1)
+
+    def test_x_times_neg_one_negates(self):
+        assert (P(1) * C(-1)).calculate({1: 5.0}) == pytest.approx(-5.0)
+
+    def test_neg_one_times_x_negates(self):
+        assert (C(-1) * P(1)).calculate({1: 5.0}) == pytest.approx(-5.0)
+
+    def test_x_minus_zero(self):
+        assert P(1) - C(0) == P(1)
+
+    def test_zero_minus_x_is_neg_x(self):
+        assert (C(0) - P(1)).calculate({1: 5.0}) == pytest.approx(-5.0)
+
+    def test_x_minus_x_is_zero(self):
+        p = P(1)
+        assert p - p == C(0)
+
+    def test_x_minus_neg_y_is_x_plus_y(self):
+        assert (P(1) - (-P(2))).calculate({1: 3.0, 2: 4.0}) == pytest.approx(7.0)
+
+    def test_x_div_one(self):
+        assert P(1) / C(1) == P(1)
+
+    def test_x_div_neg_one_negates(self):
+        assert (P(1) / C(-1)).calculate({1: 5.0}) == pytest.approx(-5.0)
+
+    def test_x_div_x_is_one(self):
+        p = P(1)
+        assert p / p == C(1)
+
+    def test_neg_x_times_neg_y_cancels(self):
+        assert ((-P(1)) * (-P(2))).calculate({1: 3.0, 2: 4.0}) == pytest.approx(12.0)
+
+    def test_neg_x_div_neg_y_cancels(self):
+        assert ((-P(1)) / (-P(2))).calculate({1: 6.0, 2: 3.0}) == pytest.approx(2.0)
+
+    def test_x_plus_neg_y_becomes_subtraction(self):
+        assert (P(1) + (-P(2))).calculate({1: 10.0, 2: 3.0}) == pytest.approx(7.0)
+
+    def test_neg_x_plus_y_reverses_subtraction(self):
+        assert ((-P(1)) + P(2)).calculate({1: 3.0, 2: 10.0}) == pytest.approx(7.0)
+
+    def test_x_mul_neg_y_pulls_negation_out(self):
+        e = P(1) * (-P(2))
+        assert isinstance(e, NegatedExpression)
+        assert e.calculate({1: 3.0, 2: 4.0}) == pytest.approx(-12.0)
+
+    def test_neg_x_mul_y_pulls_negation_out(self):
+        e = (-P(1)) * P(2)
+        assert isinstance(e, NegatedExpression)
+        assert e.calculate({1: 3.0, 2: 4.0}) == pytest.approx(-12.0)
+
+    def test_x_div_neg_y_pulls_negation_out(self):
+        e = P(1) / (-P(2))
+        assert isinstance(e, NegatedExpression)
+        assert e.calculate({1: 6.0, 2: 3.0}) == pytest.approx(-2.0)
+
+    def test_neg_x_div_y_pulls_negation_out(self):
+        e = (-P(1)) / P(2)
+        assert isinstance(e, NegatedExpression)
+        assert e.calculate({1: 6.0, 2: 3.0}) == pytest.approx(-2.0)
+
+
+class TestNegatedExpression:
+    def test_double_negation(self):
+        p = P(1)
+        assert -(-p) == p
+
+    def test_double_negation_evaluates_correctly(self):
+        assert (-(-P(1))).calculate({1: 5.0}) == pytest.approx(5.0)
+
+    def test_negation_of_constant_folds(self):
+        assert -C(5) == C(-5)
+
+    def test_negation_of_subtraction_flips_operands(self):
+        # -(a - b) == b - a
+        assert (-(P(1) - P(2))).calculate({1: 3.0, 2: 7.0}) == pytest.approx(4.0)
+
+    def test_negation_of_zero_is_zero(self):
+        assert -C(0) == C(0)
+
+    def test_to_gerber_parameter_no_parens(self):
+        assert NegatedExpression(P(1)).to_gerber() == '-$1'
+
+    def test_to_gerber_operator_uses_parens(self):
+        inner = OperatorExpression(op.add, P(1), P(2))
+        assert NegatedExpression(inner).to_gerber() == '-($1+$2)'
+
+
+class TestToGerber:
+    def test_constant_integer(self):
+        assert C(5).to_gerber() == '5'
+
+    def test_constant_float(self):
+        assert C(1.5).to_gerber() == '1.5'
+
+    def test_parameter(self):
+        assert P(1).to_gerber() == '$1'
+        assert P(99).to_gerber() == '$99'
+
+    def test_add_operator(self):
+        assert OperatorExpression(op.add, P(1), P(2)).to_gerber() == '$1+$2'
+
+    def test_sub_operator(self):
+        assert OperatorExpression(op.sub, P(1), P(2)).to_gerber() == '$1-$2'
+
+    def test_mul_uses_x(self):
+        # Gerber spec uses 'x' for multiplication, not '*'
+        assert OperatorExpression(op.mul, P(1), P(2)).to_gerber() == '$1x$2'
+
+    def test_div_operator(self):
+        assert OperatorExpression(op.truediv, P(1), P(2)).to_gerber() == '$1/$2'
+
+    def test_lhs_operator_gets_parens(self):
+        lhs = OperatorExpression(op.add, P(1), P(2))
+        e = OperatorExpression(op.mul, lhs, P(3))
+        assert e.to_gerber() == '($1+$2)x$3'
+
+    def test_rhs_operator_gets_parens(self):
+        rhs = OperatorExpression(op.add, P(2), P(3))
+        e = OperatorExpression(op.mul, P(1), rhs)
+        assert e.to_gerber() == '$1x($2+$3)'
+
+    def test_nested_lhs_and_rhs_parens(self):
+        lhs = OperatorExpression(op.add, P(1), P(2))
+        outer = OperatorExpression(op.add, lhs, P(3))
+        assert outer.to_gerber() == '($1+$2)+$3'
+
+    def test_negated_mul_to_gerber(self):
+        # P(1) * (-P(2)) optimises to -(P(1)*P(2)); NegatedExpression wraps the product
+        assert (P(1) * (-P(2))).to_gerber() == '-($1x$2)'
+
+    def test_negated_div_to_gerber(self):
+        assert (P(1) / (-P(2))).to_gerber() == '-($1/$2)'
+
+    def test_negative_constant(self):
+        assert C(-5).to_gerber() == '-5'
+
+
+class TestParsing:
+    def test_constant_integer(self):
+        assert _parse_expression('5', {}, set()) == C(5)
+
+    def test_constant_float(self):
+        assert _parse_expression('1.5', {}, set()) == C(1.5)
+
+    def test_parameter_reference(self):
+        params = set()
+        assert _parse_expression('$1', {}, params) == P(1)
+        assert 1 in params
+
+    def test_multiple_parameters_tracked(self):
+        params = set()
+        _parse_expression('$1+$3', {}, params)
+        assert params == {1, 3}
+
+    def test_add(self):
+        assert _parse_expression('$1+$2', {}, set()).calculate({1: 3, 2: 4}) == pytest.approx(7)
+
+    def test_sub(self):
+        assert _parse_expression('$1-$2', {}, set()).calculate({1: 10, 2: 4}) == pytest.approx(6)
+
+    def test_mul_gerber_x_syntax(self):
+        assert _parse_expression('$1x$2', {}, set()).calculate({1: 3, 2: 4}) == pytest.approx(12)
+
+    def test_mul_uppercase_x(self):
+        assert _parse_expression('$1X$2', {}, set()).calculate({1: 3, 2: 4}) == pytest.approx(12)
+
+    def test_div(self):
+        assert _parse_expression('$1/$2', {}, set()).calculate({1: 10, 2: 4}) == pytest.approx(2.5)
+
+    def test_negation(self):
+        assert _parse_expression('-$1', {}, set()).calculate({1: 5}) == pytest.approx(-5)
+
+    def test_parenthesized(self):
+        assert _parse_expression('($1+$2)x$3', {}, set()).calculate({1: 3, 2: 4, 3: 2}) == pytest.approx(14)
+
+    def test_known_variable_becomes_variable_expression(self):
+        e = _parse_expression('$1', {1: C(10)}, set())
+        assert isinstance(e, VariableExpression)
+
+    @pytest.mark.parametrize('gerber_str,py_str,binding', [
+        ('$1+$2',         'a+b',     {1: 5,  2: 3         }),
+        ('$1-$2',         'a-b',     {1: 5,  2: 3         }),
+        ('$1x$2',         'a*b',     {1: 5,  2: 3         }),
+        ('$1/$2',         'a/b',     {1: 6,  2: 3         }),
+        ('($1+$2)x$3',    '(a+b)*c', {1: 2,  2: 3,  3: 4 }),
+        ('$1x$2+$3',      'a*b+c',   {1: 2,  2: 3,  3: 4 }),
+        ('-$1+$2',        '-a+b',    {1: 2,  2: 7         }),
+        ('$1/$2+$1x$2',   'a/b+a*b', {1: 6,  2: 2         }),
+    ])
+    def test_parse_and_evaluate(self, gerber_str, py_str, binding):
+        e = _parse_expression(gerber_str, {}, set())
+        a = binding.get(1, 0)
+        b = binding.get(2, 0)
+        c = binding.get(3, 0)
+        expected = eval(py_str)  # noqa: S307 – controlled test literals only
+        assert e.calculate(binding) == pytest.approx(expected)
+
+    @pytest.mark.parametrize('make_expr,binding', [
+        (lambda p1, p2, p3: p1 + p2,                {1: 3,  2: 7,  3: 0}),
+        (lambda p1, p2, p3: p1 - p2,                {1: 10, 2: 3,  3: 0}),
+        (lambda p1, p2, p3: p1 * p2,                {1: 3,  2: 4,  3: 0}),
+        (lambda p1, p2, p3: p1 / p2,                {1: 9,  2: 3,  3: 0}),
+        (lambda p1, p2, p3: (p1 + p2) * p3,         {1: 2,  2: 3,  3: 4}),
+        (lambda p1, p2, p3: p1 * p2 - p3,           {1: 5,  2: 2,  3: 3}),
+        (lambda p1, p2, p3: p1 / p2 + p3,           {1: 6,  2: 3,  3: 1}),
+        (lambda p1, p2, p3: -p1 + p2,               {1: 3,  2: 7,  3: 0}),
+        (lambda p1, p2, p3: p1 * (-p2),             {1: 3,  2: 4,  3: 0}),
+        (lambda p1, p2, p3: (-p1) * p2,             {1: 3,  2: 4,  3: 0}),
+        (lambda p1, p2, p3: p1 / (-p2),             {1: 9,  2: 3,  3: 0}),
+        (lambda p1, p2, p3: (-p1) / p2,             {1: 9,  2: 3,  3: 0}),
+        (lambda p1, p2, p3: (p1 + p2) / p3 - p1,   {1: 3,  2: 5,  3: 4}),
+        (lambda p1, p2, p3: p1 * p2 + p3 / p1,     {1: 3,  2: 4,  3: 6}),
+        (lambda p1, p2, p3: -(p1 + p2) * p3,        {1: 2,  2: 3,  3: 4}),
+    ])
+    def test_to_gerber_round_trip(self, make_expr, binding):
+        """to_gerber() followed by _parse_expression() must preserve the evaluated value."""
+        original = make_expr(P(1), P(2), P(3))
+        gerber = original.to_gerber()
+        parsed = _parse_expression(gerber, {}, set())
+        assert parsed.calculate(binding) == pytest.approx(original.calculate(binding))
+
+
+class TestUnitExpression:
+    def test_mm_to_mm_unchanged(self):
+        assert UnitExpression(C(25.4), MM).calculate(unit=MM) == pytest.approx(25.4)
+
+    def test_inch_to_mm(self):
+        assert UnitExpression(C(1.0), Inch).calculate(unit=MM) == pytest.approx(MILLIMETERS_PER_INCH)
+
+    def test_mm_to_inch(self):
+        assert UnitExpression(C(25.4), MM).calculate(unit=Inch) == pytest.approx(25.4 / MILLIMETERS_PER_INCH)
+
+    def test_inch_to_inch_unchanged(self):
+        assert UnitExpression(C(2.0), Inch).calculate(unit=Inch) == pytest.approx(2.0)
+
+    def test_none_unit_passes_through(self):
+        assert UnitExpression(C(5.0), None).calculate(unit=MM) == pytest.approx(5.0)
+
+    def test_negation_preserves_unit(self):
+        neg = -UnitExpression(C(5.0), MM)
+        assert isinstance(neg, UnitExpression) and neg.unit == MM
+        assert neg.calculate(unit=MM) == pytest.approx(-5.0)
+
+    def test_add_same_unit(self):
+        result = UnitExpression(C(3.0), MM) + UnitExpression(C(4.0), MM)
+        assert isinstance(result, UnitExpression)
+        assert result.calculate(unit=MM) == pytest.approx(7.0)
+
+    def test_add_mixed_units_converts(self):
+        # 1 inch + 1 mm, result held in Inch
+        result = UnitExpression(C(1.0), Inch) + UnitExpression(C(1.0), MM)
+        assert result.calculate(unit=Inch) == pytest.approx(1.0 + 1.0 / MILLIMETERS_PER_INCH)
+
+    def test_add_scalar_raises(self):
+        with pytest.raises(ValueError):
+            UnitExpression(C(5.0), MM) + C(3.0)
+
+    def test_radd_scalar_raises(self):
+        # BUG: asymmetric unit safety — C(3.0) + UnitExpression(...) does NOT raise because
+        # Python dispatches to Expression.__add__ first, which has no unit awareness.
+        # Only plain Python scalars (not Expression subclasses) trigger __radd__ on UnitExpression.
+        # There is no really nice fix for this, so we just leave it in for now.
+        with pytest.raises(ValueError):
+            5.0 + UnitExpression(C(5.0), MM)
+
+    def test_mul_by_scalar(self):
+        result = UnitExpression(C(3.0), MM) * C(2)
+        assert isinstance(result, UnitExpression)
+        assert result.calculate(unit=MM) == pytest.approx(6.0)
+
+    def test_div_by_scalar(self):
+        result = UnitExpression(C(6.0), MM) / C(2)
+        assert isinstance(result, UnitExpression)
+        assert result.calculate(unit=MM) == pytest.approx(3.0)
+
+    def test_nested_unit_expression_flattens(self):
+        # Wrapping a UnitExpression in another converts rather than double-wrapping
+        inner = UnitExpression(C(1.0), Inch)
+        outer = UnitExpression(inner, MM)
+        assert not isinstance(outer.expr, UnitExpression)
+        assert outer.calculate(unit=MM) == pytest.approx(MILLIMETERS_PER_INCH)
+
+    def test_parameters_forwarded(self):
+        assert list(UnitExpression(P(1), MM).parameters()) == [P(1)]
+
+
+class TestExprHelper:
+    def test_passthrough_expression(self):
+        p = P(1)
+        assert expr(p) is p
+
+    def test_wraps_int(self):
+        result = expr(5)
+        assert isinstance(result, ConstantExpression) and result.value == 5
+
+    def test_wraps_float(self):
+        result = expr(3.14)
+        assert isinstance(result, ConstantExpression) and result.value == pytest.approx(3.14)
+
+
+class TestVariableExpression:
+    def test_optimized_non_operator_unwraps(self):
+        # A VariableExpression wrapping something that simplifies to a non-OperatorExpression
+        # should unwrap and return the simplified value directly.
+        result = VariableExpression(C(5)).optimized()
+        assert result == C(5)
+
+    def test_optimized_keeps_operator_expression(self):
+        ve = VariableExpression(OperatorExpression(op.add, P(1), P(2)))
+        assert isinstance(ve.optimized(), VariableExpression)
+
+    def test_to_gerber_without_register_uses_inner(self):
+        assert VariableExpression(C(42)).to_gerber(register_variable=None) == '42'
+
+    def test_to_gerber_with_register_allocates_dollar_variable(self):
+        allocated = {}
+
+        def register(e):
+            key = e.to_gerber()
+            if key not in allocated:
+                allocated[key] = len(allocated) + 1
+            return allocated[key]
+
+        inner = OperatorExpression(op.add, P(1), P(2))
+        result = VariableExpression(inner).to_gerber(register_variable=register)
+        assert result.startswith('$') and int(result[1:]) >= 1

tests/test_excellon.py

@@ -24,7 +24,7 @@ from scipy.spatial import KDTree
 from gerbonara.excellon import ExcellonFile
 from gerbonara.rs274x import GerberFile
 from gerbonara.cam import FileSettings
-from gerbonara.graphic_objects import Flash
+from gerbonara.graphic_objects import Arc, Flash, Line
 
 from .image_support import *
 from .utils import *
@@ -195,3 +195,108 @@ def test_syntax_error():
     assert 'test_syntax_error.exc' in exc_info.value.msg
     assert '12' in exc_info.value.msg # lineno
 
+
+@filter_syntax_warnings
+def test_easyeda_format_supports_explicit_digit_spec():
+    data = '\n'.join([
+        'M48',
+        'INCH,TZ,2.1',
+        'T01C0.0100',
+        '%',
+        'T01',
+        'X11Y11',
+        'M30',
+    ])
+
+    parsed = ExcellonFile.from_string(data)
+    assert parsed.import_settings.number_format == (2, 1)
+
+
+@filter_syntax_warnings
+def test_fmat_1_header_is_accepted():
+    data = '\n'.join([
+        'M48',
+        'INCH,TZ,2.4',
+        'FMAT,1',
+        'T01C0.0100',
+        '%',
+        'T01',
+        'X010000Y010000',
+        'X020000Y010000',
+        'M30',
+    ])
+
+    parsed = ExcellonFile.from_string(data)
+    drills = list(parsed.drills())
+    assert len(drills) == 2
+
+
+@filter_syntax_warnings
+def test_inline_g85_slot_creates_line_slot():
+    data = '\n'.join([
+        'M48',
+        'INCH,TZ',
+        'T01C0.1000',
+        '%',
+        'T01',
+        'X080000Y015000G85X090000Y015000',
+        'M30',
+    ])
+
+    parsed = ExcellonFile.from_string(data)
+    slots = list(parsed.slots())
+    assert len(slots) == 1
+    assert isinstance(slots[0], Line)
+    assert slots[0].x1 == 8.0
+    assert slots[0].y1 == 1.5
+    assert slots[0].x2 == 9.0
+    assert slots[0].y2 == 1.5
+
+
+@filter_syntax_warnings
+def test_circular_interpolation_uses_signed_center_and_direction():
+    data = '\n'.join([
+        'M48',
+        'INCH,TZ',
+        'T01C0.0100',
+        '%',
+        'T01',
+        'G00X000000Y010000',
+        'M15',
+        'G03X-010000Y000000I000000J-010000',
+        'M16',
+        'M30',
+    ])
+
+    parsed = ExcellonFile.from_string(data)
+    slots = list(parsed.slots())
+    assert len(slots) == 1
+    assert isinstance(slots[0], Arc)
+    assert slots[0].cx == 0.0
+    assert slots[0].cy == -1.0
+    assert not slots[0].clockwise
+
+
+@filter_syntax_warnings
+def test_radius_arc_interpolation_converts_to_center_offset():
+    data = '\n'.join([
+        'M48',
+        'INCH,TZ',
+        'T01C0.0100',
+        '%',
+        'T01',
+        'G00X010000Y000000',
+        'M15',
+        'G03X000000Y010000A010000',
+        'M16',
+        'M30',
+    ])
+
+    parsed = ExcellonFile.from_string(data)
+    slots = list(parsed.slots())
+    assert len(slots) == 1
+    assert isinstance(slots[0], Arc)
+    assert math.isclose(slots[0].cx, -1.0)
+    assert math.isclose(slots[0].cy, 0.0, abs_tol=1e-12)
+    assert not slots[0].clockwise
+

tests/test_rs274x.py

@@ -29,6 +29,20 @@ from gerbonara.cam import FileSettings
 from .image_support import *
 from .utils import *
 
+def test_attribute_without_value_is_stored_as_empty_tuple():
+    data = '\n'.join([
+        '%FSLAX24Y24*%',
+        '%MOIN*%',
+        '%TF.FlagLike*%',
+        '%ADD10C,0.0100*%',
+        'D10*',
+        'X0Y0D03*',
+        'M02*',
+    ])
+
+    parsed = GerberFile.from_string(data)
+    assert parsed.file_attrs['.FlagLike'] == ()
+
 # Note: We have a testcase for gitlab issues #10/#11 in therm_1.gbr, but we can't test for that at this time because
 # gerbv chokes on that gerber file and does'nt produce any output.
 REFERENCE_FILES = [ l.strip() for l in '''
@@ -623,6 +637,23 @@ def test_syntax_error():
     assert 'test_syntax_error.gbr' in exc_info.value.msg
     assert '7' in exc_info.value.msg # lineno
 
+@filter_syntax_warnings
+def test_step_repeat_rejects_huge_instance_counts():
+    data = '\n'.join([
+        'G04 test*',
+        '%MOIN*%',
+        '%FSLAX24Y24*%',
+        '%ADD10C,0.0100*%',
+        '%SRX1000Y1000I1.0J1.0*%',
+        'D10*',
+        'X0000Y0000D03*',
+        '%SR*%',
+        'M02*',
+    ])
+
+    with pytest.raises(SyntaxError, match='too many instances'):
+        GerberFile.from_string(data)
+
 @filter_syntax_warnings
 @pytest.mark.parametrize('reference', MIN_REFERENCE_FILES, indirect=True)
 def test_invert_polarity(reference, tmpfile, img_support):

uv.lock

@@ -82,7 +82,7 @@ wheels = [
 
 [[package]]
 name = "gerbonara"
-version = "1.6.1"
+version = "1.6.2"
 source = { editable = "." }
 dependencies = [
     { name = "click" },