public override object VisitCaseExpr([NotNull] SQLiteParser.CaseExprContext context)
{
var arithExprs = new List <Expr>();
var logicalExprs = new List <Expr>();
var arithExprCount = context.arith_expr().Length;
var logicalExprCount = context.logical_expr().Length;
for (var i = 0; i < arithExprCount; i++)
{
arithExprs.Add(Visit(context.arith_expr(i)) as Expr);
}
for (var i = 0; i < logicalExprCount; i++)
{
logicalExprs.Add(Visit(context.logical_expr(i)) as Expr);
}
var elseBranchCount = context.K_ELSE() != null ? 1 : 0;
var simpleBranchCount = arithExprCount - logicalExprCount - elseBranchCount;
Expr simpleBranch = simpleBranchCount == 1 ? arithExprs[0] : null;
Expr elseBranch = elseBranchCount == 1 ? arithExprs[arithExprCount - 1] : null;
int firstThenBranch = simpleBranchCount == 1 ? 1 : 0;
int thenBranchCount = arithExprCount - simpleBranchCount - elseBranchCount;
return(new CaseExpr(simpleBranch, logicalExprs, arithExprs.GetRange(firstThenBranch, thenBranchCount), elseBranch));
}
public override object VisitCaseExpr([NotNull] SQLiteParser.CaseExprContext context)
{
var exprs = new List <Expr>();
foreach (var v in context.expr())
{
exprs.Add(Visit(v) as Expr);
}
Expr elsee = null;
Expr eval = null;
int start = 0, end = exprs.Count - 1;
if (context.K_ELSE() != null)
{
elsee = exprs[end--];
if (exprs.Count % 2 == 0)
{
eval = exprs[0];
start = 1;
}
}
else
{
if (exprs.Count % 2 == 1)
{
eval = exprs[0];
start = 1;
}
}
Debug.Assert(end > start && (end - start) % 2 == 1);
var when = new List <Expr>(); var then = new List <Expr>();
for (int i = start; i <= end;)
{
when.Add(exprs[i++]); then.Add(exprs[i++]);
}
return(new CaseExpr(eval, when, then, elsee));
}
