func (cp *compiler) controlOp(n *parse.Control) Op {
return Op{cp.control(n), n.Begin(), n.End()}
}
func (cp *compiler) control(n *parse.Control) OpFunc {
switch n.Kind {
case parse.IfControl:
condOps := cp.chunkOps(n.Conditions)
bodyOps := cp.chunkOps(n.Bodies)
var elseOp Op
if n.ElseBody != nil {
elseOp = cp.chunkOp(n.ElseBody)
}
return func(ec *EvalCtx) {
for i, condOp := range condOps {
condOp.Exec(ec)
if ec.verdict {
bodyOps[i].Exec(ec)
return
}
}
if elseOp.Func != nil {
elseOp.Exec(ec)
} else {
ec.verdict = true
}
}
case parse.TryControl:
Logger.Println("compiling a try control")
bodyOp := cp.errorCaptureOp(n.Body)
var exceptOp, elseOp ValuesOp
var finallyOp Op
var exceptVarOp LValuesOp
if n.ExceptBody != nil {
if n.ExceptVar != nil {
var restOp LValuesOp
exceptVarOp, restOp = cp.lvaluesOp(n.ExceptVar)
if restOp.Func != nil {
cp.errorpf(restOp.Begin, restOp.End, "may not use @rest in except variable")
}
}
exceptOp = cp.errorCaptureOp(n.ExceptBody)
}
if n.ElseBody != nil {
elseOp = cp.errorCaptureOp(n.ElseBody)
}
if n.FinallyBody != nil {
finallyOp = cp.chunkOp(n.FinallyBody)
}
return func(ec *EvalCtx) {
e := bodyOp.Exec(ec)[0].(Error).Inner
Logger.Println("e is now", e)
if e != nil {
if exceptOp.Func != nil {
if exceptVarOp.Func != nil {
exceptVars := exceptVarOp.Exec(ec)
if len(exceptVars) != 1 {
throw(ErrArityMismatch)
}
exceptVars[0].Set(Error{e})
}
e = exceptOp.Exec(ec)[0].(Error).Inner
Logger.Println("e is now", e)
}
} else {
if elseOp.Func != nil {
e = elseOp.Exec(ec)[0].(Error).Inner
Logger.Println("e is now", e)
}
}
if finallyOp.Func != nil {
finallyOp.Exec(ec)
}
if e != nil {
throw(e)
}
}
case parse.WhileControl:
condOp := cp.chunkOp(n.Condition)
bodyOp := cp.chunkOp(n.Body)
return func(ec *EvalCtx) {
for {
condOp.Exec(ec)
if !ec.verdict {
break
}
//for condOp.Exec(ec)[0].(Error).Inner == nil {
ex := ec.PEval(bodyOp)
if ex == Continue {
// do nothing
} else if ex == Break {
break
} else if ex != nil {
throw(ex)
}
}
ec.verdict = true
}
case parse.ForControl:
iteratorOp, restOp := cp.lvaluesOp(n.Iterator)
if restOp.Func != nil {
cp.errorpf(restOp.Begin, restOp.End, "may not use @rest in iterator")
}
valuesOp := cp.arrayOp(n.Array)
bodyOp := cp.chunkOp(n.Body)
return func(ec *EvalCtx) {
iterators := iteratorOp.Exec(ec)
if len(iterators) != 1 {
throw(ErrArityMismatch)
}
iterator := iterators[0]
values := valuesOp.Exec(ec)
for _, v := range values {
iterator.Set(v)
ex := ec.PEval(bodyOp)
if ex == Continue {
// do nothing
} else if ex == Break {
break
} else if ex != nil {
throw(ex)
}
}
}
case parse.BeginControl:
return cp.chunk(n.Body)
default:
cp.errorpf(n.Begin(), n.End(), "unknown ControlKind %s, compiler bug", n.Kind)
panic("unreachable")
}
}