public override Runtime.Object GenerateRuntimeObject()
{
// End = end flow immediately
// Done = return from thread or instruct the flow that it's safe to exit
if (isEnd)
{
return(Runtime.ControlCommand.End());
}
if (isDone)
{
return(Runtime.ControlCommand.Done());
}
runtimeDivert = new Runtime.Divert();
// Normally we resolve the target content during the
// Resolve phase, since we expect all runtime objects to
// be available in order to find the final runtime path for
// the destination. However, we need to resolve the target
// (albeit without the runtime target) early so that
// we can get information about the arguments - whether
// they're by reference - since it affects the code we
// generate here.
ResolveTargetContent();
CheckArgumentValidity();
// Passing arguments to the knot
bool requiresArgCodeGen = arguments != null && arguments.Count > 0;
if (requiresArgCodeGen || isFunctionCall || isTunnel || isThread)
{
var container = new Runtime.Container();
// Generate code for argument evaluation
// This argument generation is coded defensively - it should
// attempt to generate the code for all the parameters, even if
// they don't match the expected arguments. This is so that the
// parameter objects themselves are generated correctly and don't
// get into a state of attempting to resolve references etc
// without being generated.
if (requiresArgCodeGen)
{
// Function calls already in an evaluation context
if (!isFunctionCall)
{
container.AddContent(Runtime.ControlCommand.EvalStart());
}
List <FlowBase.Argument> targetArguments = null;
if (targetContent)
{
targetArguments = (targetContent as FlowBase).arguments;
}
for (var i = 0; i < arguments.Count; ++i)
{
Expression argToPass = arguments [i];
FlowBase.Argument argExpected = null;
if (targetArguments != null && i < targetArguments.Count)
{
argExpected = targetArguments [i];
}
// Pass by reference: argument needs to be a variable reference
if (argExpected != null && argExpected.isByReference)
{
var varRef = argToPass as VariableReference;
if (varRef == null)
{
Error("Expected variable name to pass by reference to 'ref " + argExpected.name + "' but saw " + argToPass.ToString());
break;
}
// Check that we're not attempting to pass a read count by reference
var targetPath = new Path(varRef.path);
Parsed.Object targetForCount = targetPath.ResolveFromContext(this);
if (targetForCount != null)
{
Error("can't pass a read count by reference. '" + targetPath.dotSeparatedComponents + "' is a knot/stitch/label, but '" + target.dotSeparatedComponents + "' requires the name of a VAR to be passed.");
break;
}
var varPointer = new Runtime.VariablePointerValue(varRef.name);
container.AddContent(varPointer);
}
// Normal value being passed: evaluate it as normal
else
{
argToPass.GenerateIntoContainer(container);
}
}
// Function calls were already in an evaluation context
if (!isFunctionCall)
{
container.AddContent(Runtime.ControlCommand.EvalEnd());
}
}
// Starting a thread? A bit like a push to the call stack below... but not.
// It sort of puts the call stack on a thread stack (argh!) - forks the full flow.
if (isThread)
{
container.AddContent(Runtime.ControlCommand.StartThread());
}
// If this divert is a function call, tunnel, we push to the call stack
// so we can return again
else if (isFunctionCall || isTunnel)
{
runtimeDivert.pushesToStack = true;
runtimeDivert.stackPushType = isFunctionCall ? Runtime.PushPopType.Function : Runtime.PushPopType.Tunnel;
}
// Jump into the "function" (knot/stitch)
container.AddContent(runtimeDivert);
return(container);
}
// Simple divert
else
{
return(runtimeDivert);
}
}
protected FlowBase.Argument FlowDeclArgument()
{
// Possible forms:
// name
// -> name (variable divert target argument
// ref name
// ref -> name (variable divert target by reference)
var firstIden = Parse(Identifier);
Whitespace ();
var divertArrow = ParseDivertArrow ();
Whitespace ();
var secondIden = Parse(Identifier);
if (firstIden == null && secondIden == null)
return null;
var flowArg = new FlowBase.Argument ();
if (divertArrow != null) {
flowArg.isDivertTarget = true;
}
// Passing by reference
if (firstIden == "ref") {
if (secondIden == null) {
Error ("Expected an parameter name after 'ref'");
}
flowArg.name = secondIden;
flowArg.isByReference = true;
}
// Simple argument name
else {
if (flowArg.isDivertTarget) {
flowArg.name = secondIden;
} else {
flowArg.name = firstIden;
}
if (flowArg.name == null) {
Error ("Expected an parameter name");
}
flowArg.isByReference = false;
}
return flowArg;
}
// Returns false if there's an error
void CheckArgumentValidity()
{
if (isEmpty)
{
return;
}
// Argument passing: Check for errors in number of arguments
var numArgs = 0;
if (arguments != null && arguments.Count > 0)
{
numArgs = arguments.Count;
}
// Missing content?
// Can't check arguments properly. It'll be due to some
// other error though, so although there's a problem and
// we report false, we don't need to report a specific error.
// It may also be because it's a valid call to an external
// function, that we check at the resolve stage.
if (targetContent == null)
{
return;
}
FlowBase targetFlow = targetContent as FlowBase;
// No error, crikey!
if (numArgs == 0 && (targetFlow == null || !targetFlow.hasParameters))
{
return;
}
if (targetFlow == null && numArgs > 0)
{
Error("target needs to be a knot or stitch in order to pass arguments");
return;
}
if (targetFlow.arguments == null && numArgs > 0)
{
Error("target (" + targetFlow.name + ") doesn't take parameters");
return;
}
if (this.parent is DivertTarget)
{
if (numArgs > 0)
{
Error("can't store arguments in a divert target variable");
}
return;
}
var paramCount = targetFlow.arguments.Count;
if (paramCount != numArgs)
{
string butClause;
if (numArgs == 0)
{
butClause = "but there weren't any passed to it";
}
else if (numArgs < paramCount)
{
butClause = "but only got " + numArgs;
}
else
{
butClause = "but got " + numArgs;
}
Error("to '" + targetFlow.name + "' requires " + paramCount + " arguments, " + butClause);
return;
}
// Light type-checking for divert target arguments
for (int i = 0; i < paramCount; ++i)
{
FlowBase.Argument flowArg = targetFlow.arguments [i];
Parsed.Expression divArgExpr = arguments [i];
// Expecting a divert target as an argument, let's do some basic type checking
if (flowArg.isDivertTarget)
{
// Not passing a divert target or any kind of variable reference?
var varRef = divArgExpr as VariableReference;
if (!(divArgExpr is DivertTarget) && varRef == null)
{
Error("Target '" + targetFlow.name + "' expects a divert target for the parameter named -> " + flowArg.name + " but saw " + divArgExpr, divArgExpr);
}
// Passing 'a' instead of '-> a'?
// i.e. read count instead of divert target
else if (varRef != null)
{
// Unfortunately have to manually resolve here since we're still in code gen
var knotCountPath = new Path(varRef.path);
Parsed.Object targetForCount = knotCountPath.ResolveFromContext(varRef);
if (targetForCount != null)
{
Error("Passing read count of '" + knotCountPath.dotSeparatedComponents + "' instead of a divert target. You probably meant '" + knotCountPath + "'");
}
}
}
}
if (targetFlow == null)
{
Error("Can't call as a function or with arguments unless it's a knot or stitch");
return;
}
return;
}
// Returns false if there's an error
void CheckArgumentValidity()
{
if (isToGather)
{
return;
}
// Argument passing: Check for errors in number of arguments
var numArgs = 0;
if (arguments != null && arguments.Count > 0)
{
numArgs = arguments.Count;
}
// Missing content?
// Can't check arguments properly. It'll be due to some
// other error though, so although there's a problem and
// we report false, we don't need to report a specific error.
// It may also be because it's a valid call to an external
// function, that we check at the resolve stage.
if (targetContent == null)
{
return;
}
FlowBase targetFlow = targetContent as FlowBase;
// No error, crikey!
if (numArgs == 0 && (targetFlow == null || !targetFlow.hasParameters))
{
return;
}
if (targetFlow == null && numArgs > 0)
{
Error("target needs to be a knot or stitch in order to pass arguments");
return;
}
if (targetFlow.arguments == null && numArgs > 0)
{
Error("target (" + targetFlow.name + ") doesn't take parameters");
return;
}
var paramCount = targetFlow.arguments.Count;
if (paramCount > 0 && this.parent is DivertTarget)
{
Error("Can't store a link to a knot that takes parameters in a variable");
return;
}
if (paramCount != numArgs)
{
string butClause;
if (numArgs == 0)
{
butClause = "but there weren't any passed to it";
}
else if (numArgs < paramCount)
{
butClause = "but only got " + numArgs;
}
else
{
butClause = "but got " + numArgs;
}
Error("to '" + targetFlow.name + "' requires " + paramCount + " arguments, " + butClause);
return;
}
// Light type-checking for divert target arguments
for (int i = 0; i < paramCount; ++i)
{
FlowBase.Argument flowArg = targetFlow.arguments [i];
Parsed.Expression divArgExpr = arguments [i];
if (flowArg.isDivertTarget)
{
if (!(divArgExpr is VariableReference || divArgExpr is DivertTarget))
{
Error("Target '" + targetFlow.name + "' expects a divert target for the parameter named -> " + flowArg.name + " but saw " + divArgExpr, divArgExpr);
}
}
}
if (targetFlow == null)
{
Error("Can't call as a function or with arguments unless it's a knot or stitch");
return;
}
return;
}