1 files changed, 185 insertions, 0 deletions
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())