Expression: Add test for expression clone/re-create and fix Cast

loki/expression/symbols.py

@@ -1424,17 +1424,26 @@ class Cast(pmbl.Call):
     Internal representation of a data type cast.
     """
 
+    init_arg_names = ('name', 'expression', 'kind')
+
     def __init__(self, name, expression, kind=None, **kwargs):
         assert kind is None or isinstance(kind, pmbl.Expression)
         self.kind = kind
         super().__init__(pmbl.make_variable(name), as_tuple(expression), **kwargs)
 
+    def __getinitargs__(self):
+        return (self.name, self.expression, self.kind)
+
     mapper_method = intern('map_cast')
 
     @property
     def name(self):
         return self.function.name
 
+    @property
+    def expression(self):
+        self.parameters
+
 
 class Range(StrCompareMixin, pmbl.Slice):
     """

loki/expression/tests/test_symbols.py

@@ -0,0 +1,75 @@
+# (C) Copyright 2018- ECMWF.
+# This software is licensed under the terms of the Apache Licence Version 2.0
+# which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
+# In applying this licence, ECMWF does not waive the privileges and immunities
+# granted to it by virtue of its status as an intergovernmental organisation
+# nor does it submit to any jurisdiction.
+
+import pytest
+
+from loki.expression import symbols as sym
+from loki.scope import Scope
+from loki.types import BasicType, ProcedureType, SymbolAttributes
+
+
+def test_symbol_recreation():
+    """ """
+    scope = Scope()
+    int_type = SymbolAttributes(BasicType.INTEGER, parameter=True)
+    real_type = SymbolAttributes(BasicType.REAL, kind='rick')
+    log_type = SymbolAttributes(BasicType.LOGICAL)
+    deferred_type = SymbolAttributes(BasicType.DEFERRED)
+    proc_type = SymbolAttributes(
+        ProcedureType(name='f', is_function=True, return_type=real_type)
+    )
+
+    i = sym.Scalar(name='i', type=int_type, scope=scope)
+    a = sym.Array(name='a', type=real_type, scope=scope)
+    b = sym.Variable(
+        name='b', dimensions=(i,), type=int_type, scope=scope
+    )
+    t = sym.Scalar(name='t', type=log_type, scope=scope)
+    f = sym.ProcedureSymbol(name='f', type=proc_type, scope=scope)
+
+    # Basic variables and symbols
+    exprs = [i, a, b, t, f]
+
+    # Literals
+    exprs.append( sym.FloatLiteral(66.6) )
+    exprs.append( sym.IntLiteral(42) )
+    exprs.append( sym.LogicLiteral(True) )
+    exprs.append( sym.StringLiteral('Dave') )
+
+    # Operations
+    exprs.append( sym.Sum((b, a)) )  # b(i) + a
+    exprs.append( sym.Product((b, a)) )  # b(i) +* a
+    exprs.append( sym.Sum((b, sym.Product((-1, a)))))  # b(i) - a
+    exprs.append( sym.Quotient(numerator=b, denominator=a) )  # b(i) / a
+
+    exprs.append( sym.Comparison(b, '==', a) )  # b(i) == a
+    exprs.append( sym.LogicalNot(t) )
+    exprs.append( sym.LogicalAnd((t, sym.LogicalNot(t))) )
+    exprs.append( sym.LogicalOr((t, sym.LogicalNot(t))) )
+
+    # Slightly special symbol types
+    exprs.append( sym.InlineCall(function=f, parameters=(a, b)) )
+    exprs.append( sym.Range((sym.IntLiteral(1), i)) )
+    exprs.append( sym.LoopRange((sym.IntLiteral(1), i)) )
+    exprs.append( sym.RangeIndex((sym.IntLiteral(1), i)) )
+
+    exprs.append( sym.Cast(name='int', expression=b, kind=i) )
+    exprs.append( sym.Reference(expression=b) )
+    exprs.append( sym.Dereference(expression=b) )
+
+    for expr in exprs:
+        # Check that Pymbolic-style re-generation works for all
+        # TODO: Should we introduce a Mixin "Cloneable" to makes these sane?
+        cargs = dict(zip(expr.init_arg_names, expr.__getinitargs__()))
+        clone = type(expr)(**cargs)
+        assert clone == expr
+
+        if isinstance(expr, sym.TypedSymbol):
+            # Check that TypedSymbols replicate scope via .clone()
+            scoped_clone = expr.clone()
+            assert scoped_clone == expr
+            assert scoped_clone.scope == expr.scope