public DekiScriptOutputBuffer.Range Visit(DekiScriptSwitch expr, DekiScriptExpressionEvaluationState state)
{
DekiScriptLiteral value = state.Pop(expr.Value.VisitWith(this, state));
DekiScriptSwitch.CaseBlock caseBlock = null;
// have to use for instead of foreach, since a fallthrough default case needs to be able to look ahead
for (int i = 0; i < expr.Cases.Length; i++)
{
DekiScriptSwitch.CaseBlock current = expr.Cases[i];
// check for default case
foreach (DekiScriptExpression condition in current.Conditions)
{
if (condition == null)
{
// check if this is the first default we've found
if (caseBlock == null)
{
caseBlock = current;
}
// continue in case loop, since default only gets executed if there is no match
continue;
}
// evaluate test
DekiScriptExpression test = DekiScriptExpression.BinaryOp(current.Location, DekiScriptBinary.Op.Equal, value, condition);
DekiScriptLiteral caseMatch = state.Pop(test.VisitWith(this, state));
// evaluate body on success
if (!caseMatch.IsNilFalseZero)
{
// found a matching cast statement
caseBlock = current;
break;
}
}
}
// haven't found a match yet, so if we have a default, return it
if (caseBlock != null)
{
int marker = state.Buffer.Marker;
try {
return(caseBlock.Body.VisitWith(this, state));
} catch (DekiScriptBreakException) {
// nothing to do
}
return(state.Buffer.Since(marker));
}
return(DekiScriptOutputBuffer.Range.Empty);
}
public DekiScriptLiteral Visit(DekiScriptSwitch expr, DekiScriptEnv env)
{
DekiScriptLiteral value = expr.Value.VisitWith(this, env);
DekiScriptCaseBlock defaultCase = null;
// have to use for instead of foreach, since a fallthrough default case needs to be able to look ahead
for (int i = 0; i < expr.Cases.Length; i++)
{
DekiScriptCaseBlock c = expr.Cases[i];
// check for default case
DekiScriptEnv locals = env.NewLocalScope();
foreach (DekiScriptExpression condition in c.Conditions)
{
if (condition == null)
{
// check if this is the first default we've found
if (defaultCase == null)
{
defaultCase = c;
}
// continue in case loop, since default only gets executed if there is no match
continue;
}
// evaluate test
DekiScriptBinary test = new DekiScriptBinary(0, 0, DekiScriptBinary.Op.Equal, value, condition);
DekiScriptLiteral caseMatch = test.VisitWith(this, locals);
// evaluate body on success
if (!caseMatch.IsNilFalseZero)
{
return(EvalBody(locals, c.Body));
}
}
}
// haven't found a match yet, so if we have a default, return it
if (defaultCase != null)
{
return(EvalBody(env.NewLocalScope(), defaultCase.Body));
}
return(DekiScriptNil.Value);
}
public DekiScriptExpression Visit(DekiScriptSwitch expr, DekiScriptExpressionEvaluationState state)
{
DekiScriptExpression value = expr.Value.VisitWith(this, state);
List <DekiScriptSwitch.CaseBlock> cases = new List <DekiScriptSwitch.CaseBlock>();
int defaultCaseIndex = -1;
for (int i = 0; i < expr.Cases.Length; ++i)
{
bool isDefaultCase;
object outcome = Optimize(expr.Cases[i], value, state, out isDefaultCase);
if (outcome is DekiScriptExpression)
{
return((DekiScriptExpression)outcome);
}
if (outcome != null)
{
cases.Add((DekiScriptSwitch.CaseBlock)outcome);
}
// check if case block contains a default case statement
if (isDefaultCase && (defaultCaseIndex == -1))
{
defaultCaseIndex = cases.Count - 1;
}
}
// check if all matches failed, but we found a default branch
if ((cases.Count == 1) && (defaultCaseIndex == 0) && (cases[0].Conditions.Length == 1))
{
return(cases[0].Body);
}
if (cases.Count > 0)
{
return(DekiScriptExpression.SwitchStatement(expr.Location, value, cases.ToArray()));
}
return(DekiScriptNil.Value);
}
void CaseStatement(out DekiScriptSwitch.CaseBlock block) {
List<DekiScriptExpression> conditions = new List<DekiScriptExpression>();
DekiScriptExpression caseexpr = null;
DekiScriptExpression expr = DekiScriptNil.Value;
Location location = t.Location;
if (la.kind == 30) {
Get();
Expression(out caseexpr);
Expect(31);
conditions.Add(caseexpr);
} else if (la.kind == 32) {
Get();
Expect(31);
conditions.Add(null);
} else SynErr(81);
while (la.kind == 30 || la.kind == 32) {
if (la.kind == 30) {
Get();
Expression(out caseexpr);
Expect(31);
conditions.Add(caseexpr);
} else {
Get();
Expect(31);
conditions.Add(null);
}
}
if (StartOf(1)) {
if (la.kind == 9) {
Get();
if (StartOf(1)) {
Statements(out expr);
}
Expect(10);
} else {
Statements(out expr);
}
}
block = DekiScriptExpression.SwitchCaseBlock(location, conditions, expr);
}
