public BELArray SortBy(ExecutionContext ctx, Block block)
{
ArrayList answer = new ArrayList(Array);
try
{
answer.Sort(new CustomSorter(block, ctx));
}
catch (InvalidOperationException e)
{
throw e.InnerException;
}
return new BELArray(answer);
}
public CustomSorter(Block b, ExecutionContext c)
{
block = b;
ctx = c;
}
public BELArray Collect(ExecutionContext ctx, Block block)
{
BELArray answer = new BELArray();
foreach (IBELObject each in Array)
{
ArrayList parms = new ArrayList();
parms.Add(each);
answer.Add(block.Value(ctx, parms));
}
return answer;
}
public BELArray Select(ExecutionContext ctx, Block block)
{
BELArray answer = new BELArray();
foreach (IBELObject each in Array)
{
ArrayList parms = new ArrayList();
parms.Add(each);
IBELObject objValue = block.Value(ctx, parms);
BELBoolean test = objValue as BELBoolean;
if (test == null)
throw new ExecutionException("Select block must evaluate to a boolean. Got " + BELType.BELTypeForType(objValue.GetType()).ExternalTypeName + " instead.");
if (test.Value)
answer.Add(each);
}
return answer;
}
public IBELObject WhileTrue(ExecutionContext ctx, Block block)
{
if (ParameterCount != 0)
throw new ArgumentException("Conditional block for WhileTrue can't accept parameters.");
return Loop(ctx, block, true);
}
IBELObject Loop(ExecutionContext ctx, Block block, bool halt)
{
while (true)
{
IBELObject objValue = Value(ctx);
BELBoolean test = objValue as BELBoolean;
if (test == null)
throw new ExecutionException(ctx.CurrentLocation, "WhileTrue/WhileFalse block must evaluate to a boolean. Got " + BELType.BELTypeForType(objValue.GetType()).ExternalTypeName + " instead.");
if (test.Value == halt)
break;
}
return BELString.Empty;
}
public IBELObject IfNotNull(ExecutionContext ctx, Block block)
{
return Instance;
}
public IBELObject IfNotNullElse(ExecutionContext ctx, Block notNullBlock, Block nullBlock)
{
return nullBlock.Value(ctx);
}
public IBELObject IfNull(ExecutionContext ctx, Block block)
{
return block.Value(ctx);
}
public BELArray SortBy(ExecutionContext ctx, Block block)
{
// This code formerly sorted the list by having the IComparer do the comparison.
// This was resulting in lots of superficial comparisons, as the block was being
// evaluated lots of extra times - for the left and the right item on every comparison.
// Instead, I changed it to rip through the array, evaluate the block exaclty once
// for each item, and then do the sort on just the values.
List<BelArrayEntry> entries = new List<BelArrayEntry>();
try
{
foreach (IBELObject entry in Array)
{
ArrayList a1 = new ArrayList();
a1.Add(entry);
IBELObject value = block.Value(ctx, a1);
IComparable comparable = value as IComparable;
if (comparable == null)
{
throw new ExecutionException(null, "Can not compare objects of type " + BELType.ExternalTypeNameForType(value.GetType()));
}
entries.Add(new BelArrayEntry(entry, comparable));
}
entries.Sort(new BelArrayEntry.Comparer());
}
catch (InvalidOperationException e)
{
throw e.InnerException;
}
BELArray results = new BELArray();
foreach (BelArrayEntry entry in entries)
{
results.Add(entry.Entry);
}
return results;
}
public virtual IBELObject IfNull(ExecutionContext ctx, Block block)
{
return UndefinedObject.Instance;
}
public IBELObject IfFalse(ExecutionContext ctx, Block block)
{
if (!Value)
return block.Value(ctx);
else
return UndefinedObject.Instance;
}
public IBELObject IfTrueIfFalse(ExecutionContext ctx, Block trueBlock, Block falseBlock)
{
if (Value)
return trueBlock.Value(ctx);
else
return falseBlock.Value(ctx);
}