Aperture macro parser works

4 files changed, 185 insertions, 1254 deletions

diff --git a/gerbonara/gerber/aperture_macros/am_expression.py b/gerbonara/gerber/aperture_macros/am_expression.py
deleted file mode 100644
index 809f60e..0000000
--- a/gerbonara/gerber/aperture_macros/am_expression.py
+++ /dev/null
@@ -1,244 +0,0 @@
-#!/usr/bin/env python
-# -*- coding: utf-8 -*-
-
-# Copyright 2021 Jan Götte <gerbonara@jaseg.de>
-
-import operator
-import re
-
-class Expression(object):
-    @property
-    def value(self):
-        return self
-
-    def optimized(self):
-        return self
-
-
-class UnitExpression(Expression):
-    def __init__(self, expr, unit):
-        self._expr = expr
-        self.unit = unit
-
-    def to_gerber(self, unit=None):
-        return self.converted(unit).optimized().to_gerber()
-
-    def __eq__(self, other):
-        return type(other) == type(self) and \
-            self.unit == other.unit and\
-            self._expr == other._expr
-
-    def __str__(self):
-        return f'<{str(self.expr)[1:-1]} {self.unit}>'
-
-    def converted(self, unit):
-        if unit is None or self.unit == unit:
-            return self._expr
-
-        elif unit == 'mm':
-            return OperatorExpression.mul(self._expr, MILLIMETERS_PER_INCH)
-
-        elif unit == 'inch':
-            return OperatorExpression.div(self._expr, MILLIMETERS_PER_INCH)
-
-        else:
-            raise ValueError('invalid unit, must be "inch" or "mm".')
-
-    def calculate(self, variable_binding={}, unit=None):
-        expr = self.converted(unit).optimized(variable_binding)
-        if not isinstance(expr, ConstantExpression):
-            raise IndexError(f'Cannot fully resolve expression due to unresolved variables: {expr} with variables {variable_binding}')
-
-
-class ConstantExpression(Expression):
-    def __init__(self, value):
-        self._value = value
-
-    @property
-    def value(self):
-        return self._value
-
-    def __float__(self):
-        return float(self._value)
-
-    def __eq__(self, other):
-        return type(self) == type(other) and self._value == other._value
-
-    def to_gerber(self, _unit=None):
-        if isinstance(self._value, str):
-            return self._value
-        return f'{self.value:.6f}'.rstrip('0').rstrip('.')
-
-    def __str__(self):
-        return f'<{self._value}>'
-
-    
-class VariableExpression(Expression):
-    def __init__(self, number):
-        self.number = number
-
-    def optimized(variable_binding={}):
-        if self.number in variable_binding:
-            return ConstantExpression(variable_binding[self.number])
-        return self
-
-    def __eq__(self, other):
-        return type(self) == type(other) and \
-                self.number == other.number
-
-    def to_gerber(self, _unit=None):
-        return f'${self.number}'
-
-    def __str__(self):
-        return f'<@{self.number}>'
-
-
-class OperatorExpression(Expression):
-    def __init__(self, op, l, r):
-        super(OperatorExpression, self).__init__(Expression.OPERATOR)
-        self.op = op
-        self.l = ConstantExpression(l) if isinstance(l, (int, float)) else l
-        self.r = ConstantExpression(r) if isinstance(r, (int, float)) else r
-
-    def __eq__(self, other):
-        return type(self) == type(other) and \
-                self.op == other.op and \
-                self.lvalue == other.lvalue and \
-                self.rvalue == other.rvalue
-
-    def optimized(self, variable_binding={}):
-        l = self.lvalue.optimized(variable_binding)
-        r = self.rvalue.optimized(variable_binding)
-        
-        if self.op in (operator.add, operator.mul):
-            if hash(r) < hash(l):
-                l, r = r, l
-
-        if isinstance(l, ConstantExpression) and isinstance(r, ConstantExpression):
-            return ConstantExpression(self.op(float(r), float(l)))
-
-        return OperatorExpression(self.op, l, r)
-        
-    def to_gerber(self, unit=None):
-        lval = self.lvalue.to_gerber(unit)
-        rval = self.rvalue.to_gerber(unit)
-        op = {OperatorExpression.ADD: '+',
-              OperatorExpression.SUB: '-',
-              OperatorExpression.MUL: 'x',
-              OperatorExpression.DIV: '/'} [self.op]
-        return f'({lval}{op}{rval})'
-
-    def __str__(self):
-        op = {operator.add: '+', operator.sub: '-', operator.mul: '*', operator.truediv: '/'}[self.op]
-        return f'<{str(self.lvalue)[1:-1]} {op} {str(self.rvalue)[1:-1]}>'
-
-operator_map = {
-        '+': operator.add,
-        '-': operator.sub,
-        'x': operator.mul,
-        'X': operator.mul,
-        '/': operator.truediv,
-    }
-
-precedence_map = {
-        operator.add : 0,
-        operator.sub : 0,
-        operator.mul : 1,
-        operator.truediv : 1,
-    }
-
-def _parse_expression(expr_str):
-    output_stack = []
-    operator_stack = []
-
-    drop_unary = lambda s: (s[0] == '-', s[1:] if s[0] in '-+' else s)
-    negate = lambda expr: OperatorExpression(operator.sub, ConstantExpression(0), expr)
-
-    # See http://faculty.cs.niu.edu/~hutchins/csci241/eval.htm
-    # We handle the unary +/- operators by including them into variable/number/parenthesis tokens.
-    for variable, number, operator, parenthesis in re.findall(r'([-+]?\$[0-9]+)|([-+]?[0-9]+)|([-+]?\(|\))|([-+xX/])', expr_str):
-        
-        if variable:
-            is_negative, variable = drop_unary(variable)
-            var_ex = VariableExpression(int(variable[1:]))
-            output_stack.append(negate(var_ex) if is_negative else var_ex)
-
-
-def _parse_expression(expr_str):
-    output_stack = []
-    operator_stack = []
-
-    drop_unary = lambda s: (s[0] == '-', s[1:] if s[0] in '-+' else s)
-    negate = lambda expr: OperatorExpression(operator.sub, ConstantExpression(0), expr)
-
-    # See http://faculty.cs.niu.edu/~hutchins/csci241/eval.htm
-    # We handle the unary +/- operators by including them into variable/number/parenthesis tokens.
-    for variable, number, operator, parenthesis in re.findall(r'([-+xX/])|([-+]?\$[0-9]+)|([-+]?[0-9]+\.?[0-9]*)|([()])', expr_str):
-        
-        if variable:
-            is_negative, variable = drop_unary(variable)
-            var_ex = VariableExpression(int(variable[1:]))
-            output_stack.append(negate(var_ex) if is_negative else var_ex)
-
-        elif number:
-            output_stack.append(ConstantExpression(float(number)))
-
-        elif parenthesis[-1] == '(': # be careful, we might have a leading unary +/- here!
-            is_negative, parenthesis = drop_unary(parenthesis)
-            if is_negative:
-                operator_stack.push('-')
-            operator_stack.push('(')
-
-        elif parenthesis == ')': # here we cannot have a leading unary +/-
-            if not operator_stack:
-                raise SyntaxError('Unbalanced parenthesis in aperture macro expression')
-
-            while operator_stack and not operator_stack[-1] == '(':
-                op = operator_stack.pop()
-                l, r = output_stack.pop(), output_stack.pop()
-                output_stack.append(OperatorExpression(op, l, r))
-
-            assert output_stack.pop() == '('
-            if output_stack[-1] == '-':
-                output_stack.append(negate(output_stack.pop()))
-
-        elif operator:
-            operator = operator_map[operator]
-
-            if not operator_stack or operator_stack[-1] == '(':
-                operator_stack.push(operator)
-
-            else:
-                while operator_stack and operator_stack[-1] != '(' and\
-                        precedence_map[operator] <= precedence_map[operator_stack[-1]]:
-                    output_stack.append(OperatorExpression(operator_stack.pop(), output_stack.pop(), output_stack.pop()))
-                operator_stack.push(operator)
-
-    for operator in reversed(operator_stack):
-        if operator == '(':
-            raise SyntaxError('Unbalanced parenthesis in aperture macro expression')
-
-        output_stack.append(OperatorExpression(operator_stack.pop(), output_stack.pop(), output_stack.pop()))
-    print(output_stack, operator_stack)
-
-    if len(output_stack) != 1:
-        raise SyntaxError('Invalid aperture macro expression')
-
-    return output_stack[0]
-
-def parse_macro(macro, unit):
-    blocks = re.sub(r'\s', '', macro).split('*')
-    variables = {}
-    for block in blocks:
-        block = block.strip()
-        if block[0] == '$': # variable definition
-            name, expr = block.partition('=')
-            variables[int(name[1:])] = _parse_expression(expr)
-        else: # primitive
-            primitive, args = block.split(',')
-            yield PRIMITIVE_CLASSES[int(primitive)](unit=unit, args=list(map(_parse_expression, args)))
-
-if __name__ == '__main__':
-    import sys
-    for line in sys.stdin:
-        print(_parse_expression(line.strip()))
diff --git a/gerbonara/gerber/aperture_macros/am_statements.py b/gerbonara/gerber/aperture_macros/am_statements.py
deleted file mode 100644
index 61ddf42..0000000
--- a/gerbonara/gerber/aperture_macros/am_statements.py
+++ /dev/null
@@ -1,1010 +0,0 @@
-#!/usr/bin/env python
-# -*- coding: utf-8 -*-
-
-# copyright 2015 Hamilton Kibbe <ham@hamiltonkib.be> and Paulo Henrique Silva
-# <ph.silva@gmail.com>
-
-# 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.
-
-from math import asin
-import math
-
-from .primitives import *
-from .utils import validate_coordinates, inch, metric, rotate_point
-from .am_expression import AMConstantExpression
-
-
-
-# TODO: Add support for aperture macro variables
-__all__ = ['AMPrimitive', 'AMCommentPrimitive', 'AMCirclePrimitive',
-           'AMVectorLinePrimitive', 'AMOutlinePrimitive', 'AMPolygonPrimitive',
-           'AMMoirePrimitive', 'AMThermalPrimitive', 'AMCenterLinePrimitive',
-           'AMLowerLeftLinePrimitive', 'AMUnsupportPrimitive']
-
-
-class AMPrimitive(object):
-    """ Aperture Macro Primitive Base Class
-
-    Parameters
-    ----------
-    code : int
-        primitive shape code
-
-    exposure : str
-        on or off Primitives with exposure on create a slid part of
-        the macro aperture, and primitives with exposure off erase the
-        solid part created previously in the aperture macro definition.
-        .. note::
-            The erasing effect is limited to the aperture definition in
-            which it occurs.
-
-    Returns
-    -------
-    primitive : :class: `gerber.am_statements.AMPrimitive`
-
-    Raises
-    ------
-    TypeError, ValueError
-    """
-
-    def __init__(self, code, exposure=None, rotation=AMConstantExpression(0)):
-        VALID_CODES = (0, 1, 2, 4, 5, 7, 20, 21, 22, 9999)
-        if not isinstance(code, int):
-            raise TypeError('Aperture Macro Primitive code must be an integer')
-        elif code not in VALID_CODES:
-            raise ValueError('Invalid Code. Valid codes are %s.' %
-                             ', '.join(map(str, VALID_CODES)))
-        if exposure is not None and exposure.lower() not in ('on', 'off'):
-            raise ValueError('Exposure must be either on or off')
-        self.code = code
-        self.exposure = exposure.lower() if exposure is not None else None
-        self.rotation = rotation
-
-    def rotate(self, angle, center=None):
-        self.rotation = AMOperatorExpression(AMOperatorExpression.ADD, 
-                                             self.rotation, 
-                                             AMConstantExpression(float(angle)))
-        self.rotation = self.rotation.optimize()
-
-    #def to_inch(self):
-    #    raise NotImplementedError('Subclass must implement to_inch')
-
-    #def to_metric(self):
-    #    raise NotImplementedError('Subclass must implement to_metric')
-
-    #def to_gerber(self, settings=None):
-    #    raise NotImplementedError('Subclass must implement to_gerber')
-
-    #def to_instructions(self):
-    #    raise NotImplementedError('Subclass must implement to_instructions')
-
-    #def to_primitive(self, units):
-    #    """ Return a Primitive instance based on the specified macro params.
-    #    """
-    #    raise NotImplementedError('Subclass must implement to_primitive')
-
-    @property
-    def _level_polarity(self):
-        if self.exposure == 'off':
-            return 'clear'
-        return 'dark'
-
-    def __eq__(self, other):
-        return self.__dict__ == other.__dict__
-
-
-class AMCommentPrimitive(AMPrimitive):
-    """ Aperture Macro Comment primitive. Code 0
-
-    The comment primitive has no image meaning. It is used to include human-
-    readable comments into the AM command.
-
-    .. seealso::
-        `The Gerber File Format Specification <http://www.ucamco.com/files/downloads/file/81/the_gerber_file_format_specification.pdf>`_
-            **Section 4.12.3.1:** Comment, primitive code 0
-
-    Parameters
-    ----------
-    code : int
-        Aperture Macro primitive code. 0 Indicates an AMCommentPrimitive
-
-    comment : str
-        The comment as a string.
-
-    Returns
-    -------
-    CommentPrimitive : :class:`gerber.am_statements.AMCommentPrimitive`
-        An Initialized AMCommentPrimitive
-
-    Raises
-    ------
-    ValueError
-    """
-    @classmethod
-    def from_gerber(cls, primitive):
-        primitive = primitive.strip()
-        code = int(primitive[0])
-        comment = primitive[1:]
-        return cls(code, comment)
-
-    def __init__(self, code, comment):
-        if code != 0:
-            raise ValueError('Not a valid Aperture Macro Comment statement')
-        super().__init__(code)
-        self.comment = comment.strip(' *')
-
-    def to_inch(self):
-        pass
-
-    def to_metric(self):
-        pass
-
-    def to_gerber(self, settings=None):
-        return f'0 {self.comment} *'
-
-    def to_primitive(self, units):
-        """
-        Returns None - has not primitive representation
-        """
-        return None
-
-    def to_instructions(self):
-        return [(OpCode.PUSH, self.comment), (OpCode.PRIM, self.code)]
-
-    def __str__(self):
-        return '<Aperture Macro Comment: %s>' % self.comment
-
-
-class AMCirclePrimitive(AMPrimitive):
-    """ Aperture macro Circle primitive. Code 1
-
-    A circle primitive is defined by its center point and diameter.
-
-    .. seealso::
-        `The Gerber File Format Specification <http://www.ucamco.com/files/downloads/file/81/the_gerber_file_format_specification.pdf>`_
-            **Section 4.12.3.2:** Circle, primitive code 1
-
-    Parameters
-    ----------
-    code : int
-        Circle Primitive code. Must be 1
-
-    exposure : string
-        'on' or 'off'
-
-    diameter : float
-        Circle diameter
-
-    position : tuple (<float>, <float>)
-        Position of the circle relative to the macro origin
-
-    Returns
-    -------
-    CirclePrimitive : :class:`gerber.am_statements.AMCirclePrimitive`
-        An initialized AMCirclePrimitive
-
-    Raises
-    ------
-    ValueError, TypeError
-    """
-    @classmethod
-    def from_gerber(cls, primitive):
-        modifiers = primitive.strip(' *').split(',')
-        code = int(modifiers[0])
-        exposure = 'on' if float(modifiers[1]) == 1 else 'off'
-        diameter = float(modifiers[2])
-        position = (float(modifiers[3]), float(modifiers[4]))
-        return cls(code, exposure, diameter, position)
-
-    @classmethod
-    def from_primitive(cls, primitive):
-        return cls(1, 'on', primitive.diameter, primitive.position)
-
-    def __init__(self, code, exposure, diameter, position):
-        validate_coordinates(position)
-        if code != 1:
-            raise ValueError('CirclePrimitive code is 1')
-        super(AMCirclePrimitive, self).__init__(code, exposure)
-        self.diameter = diameter
-        self.position = position
-
-    def to_inch(self):
-        self.diameter = inch(self.diameter)
-        self.position = tuple([inch(x) for x in self.position])
-
-    def to_metric(self):
-        self.diameter = metric(self.diameter)
-        self.position = tuple([metric(x) for x in self.position])
-
-    def to_gerber(self, settings=None):
-        exposure = 1 if self.exposure == 'on' else 0
-        x, y = self.position
-        return f'{self.code},{exposure},{self.diameter},{x},{y}*'
-
-    def to_primitive(self, units):
-        return Circle((self.position), self.diameter, units=units, level_polarity=self._level_polarity)
-
-
-class AMVectorLinePrimitive(AMPrimitive):
-    """ Aperture Macro Vector Line primitive. Code 2 or 20.
-
-    A vector line is a rectangle defined by its line width, start, and end
-    points. The line ends are rectangular.
-
-    .. seealso::
-        `The Gerber File Format Specification <http://www.ucamco.com/files/downloads/file/81/the_gerber_file_format_specification.pdf>`_
-            **Section 4.12.3.3:** Vector Line, primitive code 2 or 20.
-
-    Parameters
-    ----------
-    code : int
-        Vector Line Primitive code. Must be either 2 or 20.
-
-    exposure : string
-        'on' or 'off'
-
-    width : float
-        Line width
-
-    start : tuple (<float>, <float>)
-        coordinate of line start point
-
-    end : tuple (<float>, <float>)
-        coordinate of line end point
-
-    rotation : float
-        Line rotation about the origin.
-
-    Returns
-    -------
-    LinePrimitive : :class:`gerber.am_statements.AMVectorLinePrimitive`
-        An initialized AMVectorLinePrimitive
-
-    Raises
-    ------
-    ValueError, TypeError
-    """
-
-    @classmethod
-    def from_primitive(cls, primitive):
-        return cls(2, 'on', primitive.aperture.width, primitive.start, primitive.end, 0)
-
-    @classmethod
-    def from_gerber(cls, primitive):
-        modifiers = primitive.strip(' *').split(',')
-        code = int(modifiers[0])
-        exposure = 'on' if float(modifiers[1]) == 1 else 'off'
-        width = float(modifiers[2])
-        start = (float(modifiers[3]), float(modifiers[4]))
-        end = (float(modifiers[5]), float(modifiers[6]))
-        rotation = float(modifiers[7])
-        return cls(code, exposure, width, start, end, rotation)
-
-    def __init__(self, code, exposure, width, start, end, rotation):
-        validate_coordinates(start)
-        validate_coordinates(end)
-        if code not in (2, 20):
-            raise ValueError('VectorLinePrimitive codes are 2 or 20')
-        super(AMVectorLinePrimitive, self).__init__(code, exposure)
-        self.width = width
-        self.start = start
-        self.end = end
-        self.rotation = rotation
-
-    def to_inch(self):
-        self.width = inch(self.width)
-        self.start = tuple([inch(x) for x in self.start])
-        self.end = tuple([inch(x) for x in self.end])
-
-    def to_metric(self):
-        self.width = metric(self.width)
-        self.start = tuple([metric(x) for x in self.start])
-        self.end = tuple([metric(x) for x in self.end])
-
-    def to_gerber(self, settings=None):
-        exp = 1 if self.exposure == 'on' else 0
-        start_x, start_y = self.start
-        end_x, end_y = self.end
-        return f'{self.code},{exp},{self.width},{start_x},{start_y},{end_x},{end_y},{self.rotation}*'
-
-    def to_primitive(self, units):
-        """
-        Convert this to a primitive. We use the Outline to represent this (instead of Line)
-        because the behaviour of the end caps is different for aperture macros compared to Lines
-        when rotated.
-        """
-
-        # Use a line to generate our vertices easily
-        line = Line(self.start, self.end, Rectangle(None, self.width, self.width))
-        vertices = line.vertices
-
-        aperture = Circle((0, 0), 0)
-
-        lines = []
-        prev_point = rotate_point(vertices[-1], self.rotation, (0, 0))
-        for point in vertices:
-            cur_point = rotate_point(point, self.rotation, (0, 0))
-
-            lines.append(Line(prev_point, cur_point, aperture))
-
-        return Outline(lines, units=units, level_polarity=self._level_polarity)
-
-
-class AMOutlinePrimitive(AMPrimitive):
-    """ Aperture Macro Outline primitive. Code 4.
-
-    An outline primitive is an area enclosed by an n-point polygon defined by
-    its start point and n subsequent points. The outline must be closed, i.e.
-    the last point must be equal to the start point. Self intersecting
-    outlines are not allowed.
-
-    .. seealso::
-        `The Gerber File Format Specification <http://www.ucamco.com/files/downloads/file/81/the_gerber_file_format_specification.pdf>`_
-            **Section 4.12.3.6:** Outline, primitive code 4.
-
-     Parameters
-    ----------
-    code : int
-        OutlinePrimitive code. Must be 6.
-
-    exposure : string
-        'on' or 'off'
-
-    start_point : tuple (<float>, <float>)
-        coordinate of outline start point
-
-    points : list of tuples (<float>, <float>)
-        coordinates of subsequent points
-
-    rotation : float
-        outline rotation about the origin.
-
-    Returns
-    -------
-    OutlinePrimitive : :class:`gerber.am_statements.AMOutlineinePrimitive`
-        An initialized AMOutlinePrimitive
-
-    Raises
-    ------
-    ValueError, TypeError
-    """
-
-    @classmethod
-    def from_primitive(cls, primitive):
-
-        start_point = (round(primitive.primitives[0].start[0], 6), round(primitive.primitives[0].start[1], 6))
-        points = []
-        for prim in primitive.primitives:
-            points.append((round(prim.end[0], 6), round(prim.end[1], 6)))
-
-        rotation = 0.0
-
-        return cls(4, 'on', start_point, points, rotation)
-
-    @classmethod
-    def from_gerber(cls, primitive):
-        modifiers = primitive.strip(' *').split(",")
-
-        code = int(modifiers[0])
-        exposure = "on" if float(modifiers[1]) == 1 else "off"
-        n = int(float(modifiers[2]))
-        start_point = (float(modifiers[3]), float(modifiers[4]))
-        points = []
-        for i in range(n):
-            points.append((float(modifiers[5 + i * 2]),
-                           float(modifiers[5 + i * 2 + 1])))
-        rotation = float(modifiers[-1])
-        return cls(code, exposure, start_point, points, rotation)
-
-    def __init__(self, code, exposure, start_point, points, rotation):
-        """ Initialize AMOutlinePrimitive
-        """
-        validate_coordinates(start_point)
-        for point in points:
-            validate_coordinates(point)
-        if code != 4:
-            raise ValueError('OutlinePrimitive code is 4')
-        super(AMOutlinePrimitive, self).__init__(code, exposure)
-        self.start_point = start_point
-        if points[-1] != start_point:
-            raise ValueError('OutlinePrimitive must be closed')
-        self.points = points
-        self.rotation = rotation
-
-    def to_inch(self):
-        self.start_point = tuple([inch(x) for x in self.start_point])
-        self.points = tuple([(inch(x), inch(y)) for x, y in self.points])
-
-    def to_metric(self):
-        self.start_point = tuple([metric(x) for x in self.start_point])
-        self.points = tuple([(metric(x), metric(y)) for x, y in self.points])
-
-    def to_gerber(self, settings=None):
-        exposure = 1 if self.exposure == 'on' else 0
-        x0, y0 = self.start_point
-        points = ",\n".join([ f'{x:.6f},{y:.6f}' for x, y in self.points ])
-        return f'{self.code},{exposure},{len(self.points)},{x0:.6f},{y0:.6f},{points},{self.rotation}*'
-
-    def to_primitive(self, units):
-        """
-        Convert this to a drawable primitive. This uses the Outline instead of Line
-        primitive to handle differences in end caps when rotated.
-        """
-
-        lines = []
-        prev_point = rotate_point(self.start_point, self.rotation)
-        for point in self.points:
-            cur_point = rotate_point(point, self.rotation)
-
-            lines.append(Line(prev_point, cur_point, Circle((0,0), 0)))
-
-            prev_point = cur_point
-
-        if lines[0].start != lines[-1].end:
-            raise ValueError('Outline must be closed')
-
-        return Outline(lines, units=units, level_polarity=self._level_polarity)
-
-
-class AMPolygonPrimitive(AMPrimitive):
-    """ Aperture Macro Polygon primitive. Code 5.
-
-    A polygon primitive is a regular polygon defined by the number of
-    vertices, the center point, and the diameter of the circumscribed circle.
-
-    .. seealso::
-        `The Gerber File Format Specification <http://www.ucamco.com/files/downloads/file/81/the_gerber_file_format_specification.pdf>`_
-            **Section 4.12.3.8:** Polygon, primitive code 5.
-
-    Parameters
-    ----------
-    code : int
-        PolygonPrimitive code. Must be 5.
-
-    exposure : string
-        'on' or 'off'
-
-    vertices : int, 3 <= vertices <= 12
-        Number of vertices
-
-    position : tuple (<float>, <float>)
-        X and Y coordinates of polygon center
-
-    diameter : float
-        diameter of circumscribed circle.
-
-    rotation : float
-        polygon rotation about the origin.
-
-    Returns
-    -------
-    PolygonPrimitive : :class:`gerber.am_statements.AMPolygonPrimitive`
-        An initialized AMPolygonPrimitive
-
-    Raises
-    ------
-    ValueError, TypeError
-    """
-
-    @classmethod
-    def from_primitive(cls, primitive):
-        return cls(5, 'on', primitive.sides, primitive.position, primitive.diameter, primitive.rotation)
-
-    @classmethod
-    def from_gerber(cls, primitive):
-        modifiers = primitive.strip(' *').split(",")
-        code = int(modifiers[0])
-        exposure = "on" if float(modifiers[1]) == 1 else "off"
-        vertices = int(float(modifiers[2]))
-        position = (float(modifiers[3]), float(modifiers[4]))
-        try:
-            diameter = float(modifiers[5])
-        except:
-            diameter = 0
-
-        rotation = float(modifiers[6])
-        return cls(code, exposure, vertices, position, diameter, rotation)
-
-    def __init__(self, code, exposure, vertices, position, diameter, rotation):
-        """ Initialize AMPolygonPrimitive
-        """
-        if code != 5:
-            raise ValueError('PolygonPrimitive code is 5')
-        super(AMPolygonPrimitive, self).__init__(code, exposure)
-        if vertices < 3 or vertices > 12:
-            raise ValueError('Number of vertices must be between 3 and 12')
-        self.vertices = vertices
-        validate_coordinates(position)
-        self.position = position
-        self.diameter = diameter
-        self.rotation = rotation
-
-    def to_inch(self):
-        self.position = tuple([inch(x) for x in self.position])
-        self.diameter = inch(self.diameter)
-
-    def to_metric(self):
-        self.position = tuple([metric(x) for x in self.position])
-        self.diameter = metric(self.diameter)
-
-    def to_gerber(self, settings=None):
-        exposure = 1 if self.exposure == 'on' else 0
-        x, y = self.position
-        return f'{self.code},{exposure},{self.vertices},{x:.4f},{y:.4f},{self.diameter:.4f},{self.rotation}*'
-
-    def to_primitive(self, units):
-        return Polygon(self.position, self.vertices, self.diameter / 2.0, 0, rotation=math.radians(self.rotation), units=units, level_polarity=self._level_polarity)
-
-
-class AMMoirePrimitive(AMPrimitive):
-    """ Aperture Macro Moire primitive. Code 6.
-
-    The moire primitive is a cross hair centered on concentric rings (annuli).
-    Exposure is always on.
-
-    .. seealso::
-        `The Gerber File Format Specification <http://www.ucamco.com/files/downloads/file/81/the_gerber_file_format_specification.pdf>`_
-            **Section 4.12.3.9:** Moire, primitive code 6.
-
-    Parameters
-    ----------
-    code : int
-        Moire Primitive code. Must be 6.
-
-    position : tuple (<float>, <float>)
-        X and Y coordinates of moire center
-
-    diameter : float
-        outer diameter of outer ring.
-
-    ring_thickness : float
-        thickness of concentric rings.
-
-    gap : float
-        gap between concentric rings.
-
-    max_rings : float
-        maximum number of rings
-
-    crosshair_thickness : float
-        thickness of crosshairs
-
-    crosshair_length : float
-        length of crosshairs
-
-    rotation : float
-        moire rotation about the origin.
-
-    Returns
-    -------
-    MoirePrimitive : :class:`gerber.am_statements.AMMoirePrimitive`
-        An initialized AMMoirePrimitive
-
-    Raises
-    ------
-    ValueError, TypeError
-    """
-    @classmethod
-    def from_gerber(cls, primitive):
-        modifiers = primitive.strip(' *').split(",")
-        code = int(modifiers[0])
-        position = (float(modifiers[1]), float(modifiers[2]))
-        diameter = float(modifiers[3])
-        ring_thickness = float(modifiers[4])
-        gap = float(modifiers[5])
-        max_rings = int(float(modifiers[6]))
-        crosshair_thickness = float(modifiers[7])
-        crosshair_length = float(modifiers[8])
-        rotation = float(modifiers[9])
-        return cls(code, position, diameter, ring_thickness, gap, max_rings, crosshair_thickness, crosshair_length, rotation)
-
-    def __init__(self, code, position, diameter, ring_thickness, gap, max_rings, crosshair_thickness, crosshair_length, rotation):
-        """ Initialize AMoirePrimitive
-        """
-        if code != 6:
-            raise ValueError('MoirePrimitive code is 6')
-        super(AMMoirePrimitive, self).__init__(code, 'on')
-        validate_coordinates(position)
-        self.position = position
-        self.diameter = diameter
-        self.ring_thickness = ring_thickness
-        self.gap = gap
-        self.max_rings = max_rings
-        self.crosshair_thickness = crosshair_thickness
-        self.crosshair_length = crosshair_length
-        self.rotation = rotation
-
-    def to_inch(self):
-        self.position = tuple([inch(x) for x in self.position])
-        self.diameter = inch(self.diameter)
-        self.ring_thickness = inch(self.ring_thickness)
-        self.gap = inch(self.gap)
-        self.crosshair_thickness = inch(self.crosshair_thickness)
-        self.crosshair_length = inch(self.crosshair_length)
-
-    def to_metric(self):
-        self.position = tuple([metric(x) for x in self.position])
-        self.diameter = metric(self.diameter)
-        self.ring_thickness = metric(self.ring_thickness)
-        self.gap = metric(self.gap)
-        self.crosshair_thickness = metric(self.crosshair_thickness)
-        self.crosshair_length = metric(self.crosshair_length)
-
-
-    def to_gerber(self, settings=None):
-        x, y = self.position
-        return f'{self.code},{x:.4f},{y:.4f},{self.diameter},{self.ring_thickness},{self.gap},{self.max_rings},{self.crosshair_thickness},{self.crosshair_length},{self.rotation}*'
-
-    def to_primitive(self, units):
-        #raise NotImplementedError()
-        return None
-
-
-class AMThermalPrimitive(AMPrimitive):
-    """ Aperture Macro Thermal primitive. Code 7.
-
-    The thermal primitive is a ring (annulus) interrupted by four gaps.
-    Exposure is always on.
-
-    .. seealso::
-        `The Gerber File Format Specification <http://www.ucamco.com/files/downloads/file/81/the_gerber_file_format_specification.pdf>`_
-            **Section 4.12.3.10:** Thermal, primitive code 7.
-
-    Parameters
-    ----------
-    code : int
-        Thermal Primitive code. Must be 7.
-
-    position : tuple (<float>, <float>)
-        X and Y coordinates of thermal center
-
-    outer_diameter : float
-        outer diameter of thermal.
-
-    inner_diameter : float
-        inner diameter of thermal.
-
-    gap : float
-        gap thickness
-
-    rotation : float
-        thermal rotation about the origin.
-
-    Returns
-    -------
-    ThermalPrimitive : :class:`gerber.am_statements.AMThermalPrimitive`
-        An initialized AMThermalPrimitive
-
-    Raises
-    ------
-    ValueError, TypeError
-    """
-    @classmethod
-    def from_gerber(cls, primitive):
-        modifiers = primitive.strip(' *').split(",")
-        code = int(modifiers[0])
-        position = (float(modifiers[1]), float(modifiers[2]))
-        outer_diameter = float(modifiers[3])
-        inner_diameter = float(modifiers[4])
-        gap = float(modifiers[5])
-        rotation = float(modifiers[6])
-        return cls(code, position, outer_diameter, inner_diameter, gap, rotation)
-
-    def __init__(self, code, position, outer_diameter, inner_diameter, gap, rotation):
-        if code != 7:
-            raise ValueError('ThermalPrimitive code is 7')
-        super(AMThermalPrimitive, self).__init__(code, 'on')
-        validate_coordinates(position)
-        self.position = position
-        self.outer_diameter = outer_diameter
-        self.inner_diameter = inner_diameter
-        self.gap = gap
-        self.rotation = rotation
-
-    def to_inch(self):
-        self.position = tuple([inch(x) for x in self.position])
-        self.outer_diameter = inch(self.outer_diameter)
-        self.inner_diameter = inch(self.inner_diameter)
-        self.gap = inch(self.gap)
-
-    def to_metric(self):
-        self.position = tuple([metric(x) for x in self.position])
-        self.outer_diameter = metric(self.outer_diameter)
-        self.inner_diameter = metric(self.inner_diameter)
-        self.gap = metric(self.gap)
-
-    def to_gerber(self, settings=None):
-        x, y = self.position
-        return f'{self.code},{x:.4f},{y:.4f},{self.outer_diameter},{self.inner_diameter},{self.gap},{self.rotation}*'
-
-    def _approximate_arc_cw(self, start_angle, end_angle, radius, center):
-        """
-        Get an arc as a series of points
-
-        Parameters
-        ----------
-        start_angle : The start angle in radians
-        end_angle : The end angle in radians
-        radius`: Radius of the arc
-        center : The center point of the arc (x, y) tuple
-
-        Returns
-        -------
-        array of point tuples
-        """
-
-        # The total sweep
-        sweep_angle = end_angle - start_angle
-        num_steps = 10
-
-        angle_step = sweep_angle / num_steps
-
-        radius = radius
-        center = center
-
-        points = []
-
-        for i in range(num_steps + 1):
-            current_angle = start_angle + (angle_step * i)
-
-            nextx = (center[0] + math.cos(current_angle) * radius)
-            nexty = (center[1] + math.sin(current_angle) * radius)
-
-            points.append((nextx, nexty))
-
-        return points
-
-    def to_primitive(self, units):
-
-        # We start with calculating the top right section, then duplicate it
-
-        inner_radius = self.inner_diameter / 2.0
-        outer_radius = self.outer_diameter / 2.0
-
-        # Calculate the start angle relative to the horizontal axis
-        inner_offset_angle = asin(self.gap / 2.0 / inner_radius)
-        outer_offset_angle = asin(self.gap / 2.0 / outer_radius)
-
-        rotation_rad = math.radians(self.rotation)
-        inner_start_angle = inner_offset_angle + rotation_rad
-        inner_end_angle =  math.pi / 2 - inner_offset_angle + rotation_rad
-
-        outer_start_angle = outer_offset_angle + rotation_rad
-        outer_end_angle = math.pi / 2 - outer_offset_angle + rotation_rad
-
-        outlines = []
-        aperture = Circle((0, 0), 0)
-
-        points = (self._approximate_arc_cw(inner_start_angle, inner_end_angle, inner_radius, self.position)
-                + list(reversed(self._approximate_arc_cw(outer_start_angle, outer_end_angle, outer_radius, self.position))))
-        # Add in the last point since outlines should be closed
-        points.append(points[0])
-
-        # There are four outlines at rotated sections
-        for rotation in [0, 90.0, 180.0, 270.0]:
-
-            lines = []
-            prev_point = rotate_point(points[0], rotation, self.position)
-            for point in points[1:]:
-                cur_point = rotate_point(point, rotation, self.position)
-
-                lines.append(Line(prev_point, cur_point, aperture))
-
-            prev_point = cur_point
-
-            outlines.append(Outline(lines, units=units, level_polarity=self._level_polarity))
-
-        return outlines
-
-
-class AMCenterLinePrimitive(AMPrimitive):
-    """ Aperture Macro Center Line primitive. Code 21.
-
-    The center line primitive is a rectangle defined by its width, height, and center point.
-
-    .. seealso::
-        `The Gerber File Format Specification <http://www.ucamco.com/files/downloads/file/81/the_gerber_file_format_specification.pdf>`_
-            **Section 4.12.3.4:** Center Line, primitive code 21.
-
-    Parameters
-    ----------
-    code : int
-        Center Line Primitive code. Must be 21.
-
-    exposure : str
-        'on' or 'off'
-
-    width : float
-        Width of rectangle
-
-    height : float
-        Height of rectangle
-
-    center : tuple (<float>, <float>)
-        X and Y coordinates of line center
-
-    rotation : float
-        rectangle rotation about its center.
-
-    Returns
-    -------
-    CenterLinePrimitive : :class:`gerber.am_statements.AMCenterLinePrimitive`
-        An initialized AMCenterLinePrimitive
-
-    Raises
-    ------
-    ValueError, TypeError
-    """
-
-    @classmethod
-    def from_primitive(cls, primitive):
-        width = primitive.width
-        height = primitive.height
-        center = primitive.position
-        rotation = math.degrees(primitive.rotation)
-        return cls(21, 'on', width, height, center, rotation)
-
-    @classmethod
-    def from_gerber(cls, primitive):
-        modifiers = primitive.strip(' *').split(",")
-        code = int(modifiers[0])
-        exposure = 'on' if float(modifiers[1]) == 1 else 'off'
-        width = float(modifiers[2])
-        height = float(modifiers[3])
-        center = (float(modifiers[4]), float(modifiers[5]))
-        rotation = float(modifiers[6])
-        return cls(code, exposure, width, height, center, rotation)
-
-    def __init__(self, code, exposure, width, height, center, rotation):
-        if code != 21:
-            raise ValueError('CenterLinePrimitive code is 21')
-        super(AMCenterLinePrimitive, self).__init__(code, exposure)
-        self.width = width
-        self.height = height
-        validate_coordinates(center)
-        self.center = center
-        self.rotation = rotation
-
-    def to_inch(self):
-        self.center = tuple([inch(x) for x in self.center])
-        self.width = inch(self.width)
-        self.height = inch(self.height)
-
-    def to_metric(self):
-        self.center = tuple([metric(x) for x in self.center])
-        self.width = metric(self.width)
-        self.height = metric(self.height)
-
-    def to_gerber(self, settings=None):
-        exposure = 1 if self.exposure == 'on' else 0
-        x, y = self.center
-        return f'{self.code},{exposure},{self.width},{self.height},{x:.4f},{y:.4f},{self.rotation}*'
-
-    def to_primitive(self, units):
-
-        x = self.center[0]
-        y = self.center[1]
-        half_width = self.width / 2.0
-        half_height = self.height / 2.0
-
-        points = []
-        points.append((x - half_width, y + half_height))
-        points.append((x - half_width, y - half_height))
-        points.append((x + half_width, y - half_height))
-        points.append((x + half_width, y + half_height))
-
-        aperture = Circle((0, 0), 0)
-
-        lines = []
-        prev_point = rotate_point(points[3], self.rotation, self.center)
-        for point in points:
-            cur_point = rotate_point(point, self.rotation, self.center)
-
-            lines.append(Line(prev_point, cur_point, aperture))
-
-        return Outline(lines, units=units, level_polarity=self._level_polarity)
-
-
-class AMLowerLeftLinePrimitive(AMPrimitive):
-    """ Aperture Macro Lower Left Line primitive. Code 22.
-
-    The lower left line primitive is a rectangle defined by its width, height, and the lower left point.
-
-    .. seealso::
-        `The Gerber File Format Specification <http://www.ucamco.com/files/downloads/file/81/the_gerber_file_format_specification.pdf>`_
-            **Section 4.12.3.5:** Lower Left Line, primitive code 22.
-
-    Parameters
-    ----------
-    code : int
-        Center Line Primitive code. Must be 22.
-
-    exposure : str
-        'on' or 'off'
-
-    width : float
-        Width of rectangle
-
-    height : float
-        Height of rectangle
-
-    lower_left : tuple (<float>, <float>)
-        X and Y coordinates of lower left corner
-
-    rotation : float
-        rectangle rotation about its origin.
-
-    Returns
-    -------
-    LowerLeftLinePrimitive : :class:`gerber.am_statements.AMLowerLeftLinePrimitive`
-        An initialized AMLowerLeftLinePrimitive
-
-    Raises
-    ------
-    ValueError, TypeError
-    """
-    @classmethod
-    def from_gerber(cls, primitive):
-        modifiers = primitive.strip(' *').split(",")
-        code = int(modifiers[0])
-        exposure = 'on' if float(modifiers[1]) == 1 else 'off'
-        width = float(modifiers[2])
-        height = float(modifiers[3])
-        lower_left = (float(modifiers[4]), float(modifiers[5]))
-        rotation = float(modifiers[6])
-        return cls(code, exposure, width, height, lower_left, rotation)
-
-    def __init__(self, code, exposure, width, height, lower_left, rotation):
-        if code != 22:
-            raise ValueError('LowerLeftLinePrimitive code is 22')
-        super (AMLowerLeftLinePrimitive, self).__init__(code, exposure)
-        self.width = width
-        self.height = height
-        validate_coordinates(lower_left)
-        self.lower_left = lower_left
-        self.rotation = rotation
-
-    def to_inch(self):
-        self.lower_left = tuple([inch(x) for x in self.lower_left])
-        self.width = inch(self.width)
-        self.height = inch(self.height)
-
-    def to_metric(self):
-        self.lower_left = tuple([metric(x) for x in self.lower_left])
-        self.width = metric(self.width)
-        self.height = metric(self.height)
-
-    def to_gerber(self, settings=None):
-        exposure = 1 if self.exposure == 'on' else 0
-        x, y = self.lower_left
-        return f'{self.code},{exposure},{self.width},{self.height},{x:.4f},{y:.4f},{self.rotation}*'
-
-
-class AMUnsupportPrimitive(AMPrimitive):
-    @classmethod
-    def from_gerber(cls, primitive):
-        return cls(primitive)
-
-    def __init__(self, primitive):
-        super(AMUnsupportPrimitive, self).__init__(9999)
-        self.primitive = primitive
-
-    def to_inch(self):
-        pass
-
-    def to_metric(self):
-        pass
-
-    def to_gerber(self, settings=None):
-        return self.primitive
-
diff --git a/gerbonara/gerber/aperture_macros/expression.py b/gerbonara/gerber/aperture_macros/expression.py
new file mode 100644
index 0000000..49df36c
--- /dev/null
+++ b/gerbonara/gerber/aperture_macros/expression.py
@@ -0,0 +1,185 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+# Copyright 2021 Jan Götte <gerbonara@jaseg.de>
+
+import operator
+import re
+import ast
+
+class Expression(object):
+    @property
+    def value(self):
+        return self
+
+    def optimized(self, variable_binding={}):
+        return self
+
+    def __str__(self):
+        return f'<{self.to_gerber()}>'
+
+class UnitExpression(Expression):
+    def __init__(self, expr, unit):
+        self._expr = expr
+        self.unit = unit
+
+    def to_gerber(self, unit=None):
+        return self.converted(unit).optimized().to_gerber()
+
+    def __eq__(self, other):
+        return type(other) == type(self) and \
+            self.unit == other.unit and\
+            self._expr == other._expr
+
+    def __str__(self):
+        return f'<{self.expr.to_gerber()} {self.unit}>'
+
+    def converted(self, unit):
+        if unit is None or self.unit == unit:
+            return self._expr
+
+        elif unit == 'mm':
+            return OperatorExpression.mul(self._expr, MILLIMETERS_PER_INCH)
+
+        elif unit == 'inch':
+            return OperatorExpression.div(self._expr, MILLIMETERS_PER_INCH)
+
+        else:
+            raise ValueError('invalid unit, must be "inch" or "mm".')
+
+    def calculate(self, variable_binding={}, unit=None):
+        expr = self.converted(unit).optimized(variable_binding)
+        if not isinstance(expr, ConstantExpression):
+            raise IndexError(f'Cannot fully resolve expression due to unresolved variables: {expr} with variables {variable_binding}')
+
+
+class ConstantExpression(Expression):
+    def __init__(self, value):
+        self._value = value
+
+    @property
+    def value(self):
+        return self._value
+
+    def __float__(self):
+        return float(self._value)
+
+    def __eq__(self, other):
+        return type(self) == type(other) and self._value == other._value
+
+    def to_gerber(self, _unit=None):
+        if isinstance(self._value, str):
+            return self._value
+        return f'{self.value:.6f}'.rstrip('0').rstrip('.')
+
+    
+class VariableExpression(Expression):
+    def __init__(self, number):
+        self.number = number
+
+    def optimized(self, variable_binding={}):
+        if self.number in variable_binding:
+            return ConstantExpression(variable_binding[self.number])
+        return self
+
+    def __eq__(self, other):
+        return type(self) == type(other) and \
+                self.number == other.number
+
+    def to_gerber(self, _unit=None):
+        return f'${self.number}'
+
+
+class OperatorExpression(Expression):
+    def __init__(self, op, l, r):
+        self.op = op
+        self.l = ConstantExpression(l) if isinstance(l, (int, float)) else l
+        self.r = ConstantExpression(r) if isinstance(r, (int, float)) else r
+
+    def __eq__(self, other):
+        return type(self) == type(other) and \
+                self.op == other.op and \
+                self.l == other.l and \
+                self.r == other.r
+
+    def optimized(self, variable_binding={}):
+        l = self.l.optimized(variable_binding)
+        r = self.r.optimized(variable_binding)
+        
+        if self.op in (operator.add, operator.mul):
+            if id(r) < id(l):
+                l, r = r, l
+
+        if isinstance(l, ConstantExpression) and isinstance(r, ConstantExpression):
+            return ConstantExpression(self.op(float(r), float(l)))
+
+        return OperatorExpression(self.op, l, r)
+        
+    def to_gerber(self, unit=None):
+        lval = self.l.to_gerber(unit)
+        rval = self.r.to_gerber(unit)
+
+        if isinstance(self.l, OperatorExpression):
+            lval = f'({lval})'
+        if isinstance(self.r, OperatorExpression):
+            rval = f'({rval})'
+
+        op = {operator.add: '+',
+              operator.sub: '-',
+              operator.mul: 'x',
+              operator.truediv: '/'} [self.op]
+
+        return f'{lval}{op}{rval}'
+
+
+def _map_expression(node):
+    if isinstance(node, ast.Num):
+        return ConstantExpression(node.n)
+
+    elif isinstance(node, ast.BinOp):
+        op_map = {ast.Add: operator.add, ast.Sub: operator.sub, ast.Mult: operator.mul, ast.Div: operator.truediv}
+        return OperatorExpression(op_map[type(node.op)], _map_expression(node.left), _map_expression(node.right))
+
+    elif isinstance(node, ast.UnaryOp):
+        if type(node.op) == ast.UAdd:
+            return _map_expression(node.operand)
+        else:
+            return OperatorExpression(operator.sub, ConstantExpression(0), _map_expression(node.operand))
+
+    elif isinstance(node, ast.Name):
+        return VariableExpression(int(node.id[3:])) # node.id has format var[0-9]+
+
+    else:
+        raise SyntaxError('Invalid aperture macro expression')
+
+def _parse_expression(expr):
+    expr = expr.lower().replace('x', '*')
+    expr = re.sub(r'\$([0-9]+)', r'var\1', expr)
+    try:
+        parsed = ast.parse(expr, mode='eval').body
+    except SyntaxError as e:
+        raise SyntaxError('Invalid aperture macro expression') from e
+    return _map_expression(parsed)
+
+def parse_macro(macro, unit):
+    blocks = re.sub(r'\s', '', macro).split('*')
+    variables = {}
+    for block in blocks:
+        block = block.strip()
+
+        if block[0:1] == '0 ': # comment
+            continue
+
+        elif block[0] == '$': # variable definition
+            name, expr = block.partition('=')
+            variables[int(name[1:])] = _parse_expression(expr)
+
+        else: # primitive
+            primitive, args = block.split(',')
+            yield PRIMITIVE_CLASSES[int(primitive)](unit=unit, args=list(map(_parse_expression, args)))
+
+if __name__ == '__main__':
+    import sys
+    for line in sys.stdin:
+        expr = _parse_expression(line.strip())
+        print(expr, '->', expr.optimized())
diff --git a/gerbonara/gerber/aperture_macros/am_primitive.py b/gerbonara/gerber/aperture_macros/primitive.py
index 88552c5..88552c5 100644
--- a/gerbonara/gerber/aperture_macros/am_primitive.py
+++ b/gerbonara/gerber/aperture_macros/primitive.py