func Die(vm *gelo.VM, args *gelo.List, ac uint) gelo.Word {
if ac == 0 {
args = gelo.AsList(gelo.StrToSym("die"))
}
gelo.RuntimeError(vm, args)
return gelo.Null //Issue 65
}
func Compose(vm *gelo.VM, args *gelo.List, ac uint) gelo.Word {
if ac == 0 {
return gelo.Alien(Id) //defined in eval.go
} else if ac == 1 {
return vm.API.InvokableOrElse(args.Value)
}
//reverse and type check (as much as possible)
builder := extensions.ListBuilder()
defer builder.Destroy()
for ; args != nil; args = args.Next {
builder.PushFront(vm.API.InvokableOrElse(args.Value))
}
fs := builder.List()
return gelo.Alien(func(vm *gelo.VM, args *gelo.List, ac uint) gelo.Word {
c := fs
var ret gelo.Word = args
for ; c.Next != nil; c = c.Next {
ret = gelo.AsList(vm.API.InvokeCmdOrElse(c.Value, ret.(*gelo.List)))
}
return vm.API.TailInvokeCmd(c.Value, ret.(*gelo.List))
})
}
func Case_of(vm *gelo.VM, args *gelo.List, ac uint) gelo.Word {
Args := _cases_parser(vm, args)
key := Args["value"]
arguments := gelo.AsList(key)
cases, ok := vm.API.PartialEval(vm.API.QuoteOrElse(Args["cases"]))
if !ok || cases.Next == nil && cases.Value == nil {
gelo.SyntaxError(vm, "Expected:", _cases_parser,
"{[value+ => resultant\n]+ [otherwise result]?} Got:", args)
}
//Give val a name, specified by var, in clauses of the cases block
//XXX This disallows us from making tail calls
if name, there := Args["var"]; there {
if d, there := vm.Ns.DepthOf(name); there && d == 0 {
defer vm.Ns.Set(0, name, vm.Ns.LookupOrElse(name))
} else {
defer vm.Ns.Del(name)
}
vm.Ns.Set(0, name, key)
}
//run val through cmd before comparing
if cmd, there := Args["cmd"]; there {
key = vm.API.InvokeCmdOrElse(cmd, arguments)
}
//Parse lines
for ; cases != nil; cases = cases.Next {
//if last line, see if it's the otherwise clause
if cases.Next == nil {
item := cases.Value.(*gelo.List)
s, ok := item.Value.(gelo.Symbol)
if ok && gelo.StrEqualsSym("otherwise", s) {
if item.Next == nil || item.Next.Next != nil {
_cases_synerr()
}
return _case_eval(vm, item.Next.Value, arguments)
}
}
item := cases.Value.(*gelo.List)
//line is too short
if item.Next == nil || item.Next.Next == nil {
_cases_synerr()
}
//Parse a single line
list := extensions.ListBuilder()
var resultant gelo.Word
for ; item != nil; item = item.Next {
if item.Next == nil { //ultimate cell
resultant = item.Value
} else if item.Next.Next == nil { //penultimate cell
s, ok := item.Value.(gelo.Symbol)
if ok && gelo.StrEqualsSym("=>", s) {
continue
}
_cases_synerr()
} else {
list.Push(item.Value)
}
}
//see if key matches any of the items we found on this line
for head := list.List(); head != nil; head = head.Next {
if key.Equals(head.Value) {
return _case_eval(vm, resultant, arguments)
}
}
}
return gelo.Null //no match, no otherwise
}