public static IExpression OptionalDeclaration(IEnumerable <VariablePrototype> variables,
IEnumerable <IExpression> rhsOptions)
{
// todo: add support for spread
if (variables.Count() != rhsOptions.Count())
{
throw new NotImplementedException();
}
// thanks to `and` parallel optional declaration uses shortcut computation
// that is, evaluating rhs options stops on the first failure
IExpression combined = null;
foreach (Tuple <VariablePrototype, IExpression> pair in variables.SyncZip(rhsOptions))
{
VariablePrototype lhs = pair.Item1;
IExpression rhs = pair.Item2;
IExpression decl = OptionalDeclaration(lhs.Name, lhs.TypeName, rhs);
if (combined == null)
{
combined = decl;
}
else
{
combined = And(combined, decl);
}
}
return(combined);
}
public IInterpreter ParallelOptionalDeclaration()
{
var interpreter = new Interpreter.Interpreter();
foreach (var mutability in Options.AllMutabilityModes)
{
var env = Language.Environment.Create(new Options()
{
DebugThrowOnError = true,
}.SetMutability(mutability));
var root_ns = env.Root;
IExpression opt_declaration = ExpressionFactory.OptionalDeclaration(new[] {
VariablePrototype.Create("x", NameFactory.Nat8NameReference()),
VariablePrototype.Create("y", NameFactory.Nat8NameReference())
}, new[] {
ExpressionFactory.OptionOf(NameFactory.Nat8NameReference(), Nat8Literal.Create("2")),
ExpressionFactory.OptionOf(NameFactory.Nat8NameReference(), Nat8Literal.Create("7")),
});
root_ns.AddBuilder(FunctionBuilder.Create("main",
ExpressionReadMode.OptionalUse,
NameFactory.Nat8NameReference(),
Block.CreateStatement(
IfBranch.CreateIf(opt_declaration,
Return.Create(ExpressionFactory.Add("x", "y")),
IfBranch.CreateElse(
ExpressionFactory.GenericThrow()
))
)));
ExecValue result = interpreter.TestRun(env);
Assert.AreEqual((byte)9, result.RetValue.PlainValue);
}
return(interpreter);
}
public override void GenerateHeaderCode(MibHeaderFile mibHeaderFile)
{
mibHeaderFile.Includes.Add(new PP_Include("lwip/apps/snmp_core.h"));
mibHeaderFile.VariableDeclarations.Add(VariablePrototype.FromVariableDeclaration(GetExportDeclaration()));
}
public IInterpreter ShortcutComputationInOptionalDeclaration()
{
var interpreter = new Interpreter.Interpreter();
foreach (var mutability in Options.AllMutabilityModes)
{
// purpose: check if RHS of the optional declaration is computed only when it is needed
// here we count RHS computations and since we declare two variables
// let (x,y) =? (None,Some)
// Some should not be executed, because `x` assigment fails first
var env = Language.Environment.Create(new Options()
{
DebugThrowOnError = true,
DiscardingAnyExpressionDuringTests = true,
}.SetMutability(mutability));
var root_ns = env.Root;
root_ns.AddBuilder(TypeBuilder.Create("Mutator")
.SetModifier(EntityModifier.Mutable)
.With(VariableDeclaration.CreateStatement("c", NameFactory.IntNameReference(), null,
env.Options.ReassignableModifier() | EntityModifier.Public)));
// return Some or None depending on the `f` parameter, and also increments the count of option evaluations
root_ns.AddBuilder(FunctionBuilder.Create("give", NameFactory.OptionNameReference(NameFactory.Nat8NameReference()),
Block.CreateStatement(
ExpressionFactory.Inc(() => NameReference.Create("m", "c")),
Return.Create(ExpressionFactory.Ternary(NameReference.Create("f"),
ExpressionFactory.OptionOf(NameFactory.Nat8NameReference(), Nat8Literal.Create("11")),
ExpressionFactory.OptionEmpty(NameFactory.Nat8NameReference())))
))
.Parameters(FunctionParameter.Create("f", NameFactory.BoolNameReference()),
FunctionParameter.Create("m", NameFactory.ReferenceNameReference(NameReference.Create("Mutator")))));
IExpression opt_declaration = ExpressionFactory.OptionalDeclaration(new[] {
VariablePrototype.Create("x", NameFactory.Nat8NameReference()),
VariablePrototype.Create("y", NameFactory.Nat8NameReference())
}, new[] {
FunctionCall.Create("give", BoolLiteral.CreateFalse(), NameReference.Create("mut")),
FunctionCall.Create("give", BoolLiteral.CreateTrue(), NameReference.Create("mut")),
});
root_ns.AddBuilder(FunctionBuilder.Create("main",
ExpressionReadMode.OptionalUse,
NameFactory.Nat8NameReference(),
Block.CreateStatement(
VariableDeclaration.CreateStatement("mut", null, ExpressionFactory.StackConstructor(NameReference.Create("Mutator"))),
IfBranch.CreateIf(opt_declaration,
new[] {
ExpressionFactory.Readout("x"),
ExpressionFactory.Readout("y"),
ExpressionFactory.GenericThrow(),
},
IfBranch.CreateElse(
// crucial check -- we should not evaluate the second option
ExpressionFactory.AssertEqual(IntLiteral.Create("1"), NameReference.Create("mut", "c"))
)),
Return.Create(Nat8Literal.Create("0"))
)));
ExecValue result = interpreter.TestRun(env);
Assert.AreEqual((byte)0, result.RetValue.PlainValue);
}
return(interpreter);
}
