ICCItem *fnSet (CEvalContext *pCtx, ICCItem *pArguments, DWORD dwData)
// fnSet
//
// Bind an identifier to some value
//
// (set var exp)
// (setq var exp)
{
CCodeChain *pCC = pCtx->pCC;
ICCItem *pArgs;
ICCItem *pVar;
ICCItem *pValue;
int iFrame, iOffset;
ICCItem *pSymTable;
// Evaluate the arguments and validate them
if (dwData == FN_SET_SET)
pArgs = pCC->EvaluateArgs(pCtx, pArguments, CONSTLIT("sv"));
else
pArgs = pCC->EvaluateArgs(pCtx, pArguments, CONSTLIT("qv"));
if (pArgs->IsError())
return pArgs;
// First is the variable; next is the value
pVar = pArgs->GetElement(0);
pValue = pArgs->GetElement(1);
// Figure out which symbol table to start with
if (pCtx->pLocalSymbols)
pSymTable = pCtx->pLocalSymbols;
else
pSymTable = pCtx->pLexicalSymbols;
// If this variable has already been bound, then use a short-cut
if (pVar->GetBinding(&iFrame, &iOffset))
{
while (iFrame > 0)
{
pSymTable = pSymTable->GetParent();
iFrame--;
}
pSymTable->AddByOffset(pCC, iOffset, pValue);
}
else
{
ICCItem *pError;
pError = pSymTable->AddEntry(pCC, pVar, pValue);
// Check for error
if (pError->IsError())
{
pArgs->Discard(pCC);
return pError;
}
pError->Discard(pCC);
}
// Keep a reference to the value, so we can return it
pValue->Reference();
// Done with these
pArgs->Discard(pCC);
// Done
return pValue;
}
ICCItem *CCodeChain::Lookup (CEvalContext *pCtx, ICCItem *pItem)
// Lookup
//
// Returns the binding for this item
{
ICCItem *pBinding = NULL;
BOOL bFound;
ICCItem *pStart;
int iFrame, iOffset;
// Start somewhere
if (pCtx->pLocalSymbols)
pStart = pCtx->pLocalSymbols;
else
pStart = pCtx->pLexicalSymbols;
// If this item already has been resolved, do a quick lookup
if (pItem->GetBinding(&iFrame, &iOffset))
{
while (iFrame > 0)
{
pStart = pStart->GetParent();
iFrame--;
}
pBinding = pStart->LookupByOffset(this, iOffset);
bFound = TRUE;
}
// Otherwise, do a lookup
else
{
bFound = FALSE;
iFrame = 0;
while (!bFound && pStart)
{
pBinding = pStart->SimpleLookup(this, pItem, &bFound, &iOffset);
if (!bFound)
{
pBinding->Discard(this);
pBinding = NULL;
pStart = pStart->GetParent();
iFrame++;
}
}
// If we found it and this is a local frame,
// set the resolution info
if (bFound && pStart->IsLocalFrame())
pItem->SetBinding(iFrame, iOffset);
}
// If there is no binding, return an error
if (!bFound)
{
ASSERT(pBinding == NULL);
//pBinding->Discard(this);
pBinding = CreateError(LITERAL("No binding for symbol"), pItem);
}
return pBinding;
}