public void CreateOnEmptySeqReturnsEmptyVector()
{
IPersistentVector v = LazilyPersistentVector.create(new object[] {});
Expect(v.count(), EqualTo(0));
}
//(case* expr shift mask default map<minhash, [test then]> table-type test-type skip-check?)
//prepared by case macro and presumed correct
//case macro binds actual expr in let so expr is always a local,
//no need to worry about multiple evaluation
public Expr Parse(ParserContext pcon, object frm)
{
ISeq form = (ISeq)frm;
if (pcon.Rhc == RHC.Eval)
{
return(Compiler.Analyze(pcon, RT.list(RT.list(Compiler.FnOnceSym, PersistentVector.EMPTY, form)), "case__" + RT.nextID()));
}
IPersistentVector args = LazilyPersistentVector.create(form.next());
object exprForm = args.nth(0);
int shift = Util.ConvertToInt(args.nth(1));
int mask = Util.ConvertToInt(args.nth(2));
object defaultForm = args.nth(3);
IPersistentMap caseMap = (IPersistentMap)args.nth(4);
Keyword switchType = (Keyword)args.nth(5);
Keyword testType = (Keyword)args.nth(6);
IPersistentSet skipCheck = RT.count(args) < 8 ? null : (IPersistentSet)args.nth(7);
ISeq keys = RT.keys(caseMap);
int low = Util.ConvertToInt(RT.first(keys));
int high = Util.ConvertToInt(RT.nth(keys, RT.count(keys) - 1));
LocalBindingExpr testexpr = (LocalBindingExpr)Compiler.Analyze(pcon.SetRhc(RHC.Expression), exprForm);
SortedDictionary <int, Expr> tests = new SortedDictionary <int, Expr>();
Dictionary <int, Expr> thens = new Dictionary <int, Expr>();
foreach (IMapEntry me in caseMap)
{
int minhash = Util.ConvertToInt(me.key());
object pair = me.val(); // [test-val then-expr]
object first = RT.first(pair);
Expr testExpr = testType == _intKey
? NumberExpr.Parse(Util.ConvertToInt(first))
: (first == null ? Compiler.NilExprInstance : new ConstantExpr(first));
tests[minhash] = testExpr;
Expr thenExpr;
thenExpr = Compiler.Analyze(pcon, RT.second(pair));
thens[minhash] = thenExpr;
}
Expr defaultExpr;
defaultExpr = Compiler.Analyze(pcon, defaultForm);
return(new CaseExpr(
(IPersistentMap)Compiler.SourceSpanVar.deref(),
testexpr,
shift,
mask,
low,
high,
defaultExpr,
tests,
thens,
switchType,
testType,
skipCheck));
}
protected override object Read(PushbackTextReader r, char leftparen, object opts)
{
return(LazilyPersistentVector.create(ReadDelimitedList(']', r, true, opts)));
}