Base expressions on dataclasses

Author: inducer

doc/index.rst

@@ -18,15 +18,15 @@ symbol, *x* in this case.
 
     >>> x = pmbl.var("x")
     >>> x
-    Variable('x')
+    Variable(name='x')
 
 Next, let's create an expression using *x*:
 
 .. doctest::
 
     >>> u = (x+1)**5
     >>> u
-    Power(Sum((Variable('x'), 1)), 5)
+    Power(base=Sum(children=(Variable(name='x'), 1)), exponent=5)
     >>> print(u)
     (x + 1)**5
 
@@ -69,20 +69,20 @@ You can also easily define your own objects to use inside an expression:
 
 .. doctest::
 
-    >>> from pymbolic.primitives import Expression
-    >>> class FancyOperator(Expression):
-    ...     def __init__(self, operand):
-    ...         self.operand = operand
-    ...
-    ...     def __getinitargs__(self):
-    ...         return (self.operand,)
+    >>> from pymbolic.primitives import Expression, augment_expression_dataclass
+    >>> from dataclasses import dataclass
+    >>>
+    >>> @augment_expression_dataclass
+    ... @dataclass(frozen=True)
+    ... class FancyOperator(Expression):
+    ...     operand: Expression
     ...
     ...     mapper_method = "map_fancy_operator"
     ...
     >>> u
-    Power(Sum((Variable('x'), 1)), 5)
+    Power(base=Sum(children=(Variable(name='x'), 1)), exponent=5)
     >>> 17*FancyOperator(u)
-    Product((17, FancyOperator(Power(Sum((..., 1)), 5))))
+    Product(children=(17, FancyOperator(operand=Power(base=Sum(children=(..., 1)), exponent=5))))
 
 As a final example, we can now derive from *MyMapper* to multiply all
 *FancyOperator* instances by 2.
@@ -93,8 +93,8 @@ As a final example, we can now derive from *MyMapper* to multiply all
     ...     def map_fancy_operator(self, expr):
     ...         return 2*FancyOperator(self.rec(expr.operand))
     ...
-    >>> MyMapper2()(FancyOperator(u))
-    Product((2, FancyOperator(Power(Product((..., 1)), 5))))
+    >>> MyMapper2()(FancyOperator(operand=u))
+    Product(children=(2, FancyOperator(operand=Power(base=Product(children=(..., 1)), exponent=5))))
 
 .. automodule:: pymbolic
 

pymbolic/parser.py

@@ -20,6 +20,7 @@
 THE SOFTWARE.
 """
 
+import immutables
 import pytools.lex
 from pytools import memoize_method
 from sys import intern
@@ -330,7 +331,8 @@ def parse_postfix(self, pstate, min_precedence, left_exp):
             args, kwargs = self.parse_arglist(pstate)
 
             if kwargs:
-                left_exp = primitives.CallWithKwargs(left_exp, args, kwargs)
+                left_exp = primitives.CallWithKwargs(
+                        left_exp, args, immutables.Map(kwargs))
             else:
                 left_exp = primitives.Call(left_exp, args)