/// <summary>
/// Generate call to a routine and store result into a variable.
/// </summary>
/// <para>Stack behavior: </para>
/// <list type="number">
/// <item><description>create new variable</description></item>
/// <item><description>store returned value</description></item>
/// <item><description>nothing left on the stack</description></item>
/// </list>
/// <param name="call">"CALL" AST fragment</param>
/// <returns>SLang variable which holds a value returned from a call.</returns>
private Variable GenerateVariableFromCall(Call call)
{
var routine = GenerateCall(call);
if (!routine.SignatureReference.ReturnType.IsVoid)
{
var variable = new BodyVariable(routine.SignatureDefinition.ReturnType);
variable.Store(ip);
return(variable);
}
return(new BodyVariable(Context.TypeSystem.Void));
}
/// <summary>
/// Generate "VARIABLE" declaration, evaluate its initializer and assign.
/// </summary>
/// <para>Stack behavior: expects nothing, leaves nothing.</para>
/// <param name="declaration">SLang IR variable declaration.</param>
private void GenerateVariableDeclaration(VariableDeclaration declaration)
{
var name = declaration.Name;
var varType = new UnitReference(Context, declaration.Type).Resolve();
Variable variable = new BodyVariable(varType, name);
// declare in the current scope
scopeCurrent.Declare(name, variable);
// evaluate initializer
var exprType = GenerateExpression(declaration.Initializer);
// assign
variable.Store(ip);
// verify
varType.AssertIsAssignableFrom(exprType);
}
/// <summary>
/// Given that instance of the underlying type is on the top of the stack, wrap it into new object of this type.
/// </summary>
/// <para>Stack behavior:</para>
/// <list type="number">
/// <item><description>raw (underlying) value is on the top of the stack</description></item>
/// <item><description>instantiate new object wrapping that value</description></item>
/// <item><description>new object is stored is a variable</description></item>
/// <item><description>stack is empty: neither raw nor boxed value</description></item>
/// </list>
/// <returns>An instance of the <see cref="Variable"/> is the only way to access the created boxed object.</returns>
public Variable Boxed(ILProcessor ip)
{
if (!IsForeign)
{
var boxed = new BodyVariable(this);
var raw = new VariableDefinition(WrappedNativeType);
ip.Body.Variables.Add(raw);
ip.Body.InitLocals = true;
ip.Emit(OpCodes.Stloc, raw);
boxed.LoadA(ip);
ip.Emit(OpCodes.Ldloc, raw);
ip.Emit(OpCodes.Call, Ctor);
return(boxed);
}
return(new BodyVariable(Context.TypeSystem.Void));
}