oeiuwq.com
An Algebraic Effect System for Golang.
Comments on Halt
+11
-3
+11
-3
fx.go
+11
-3
fx.go
···
32
32
33
33
func Ctx[V any]() Fx[V, V] { return Func(identity[V]) }
34
34
35
-
// An stopped effect that panics if resumed
35
+
// An stopped effect that panics if resumed.
36
+
// Only useful with Replace.
37
+
//
38
+
// For example, an Abort effect halts since it has no possible value for V
39
+
// but then its Handler can Replace the halted effect with an Error value.
40
+
// See: abort/result.go
36
41
func Halt[S, V any]() Fx[S, V] {
37
42
return Stop(func() Fx[S, V] {
38
43
return Fx[S, V]{
···
53
58
if e.res != nil {
54
59
return e.res()
55
60
}
56
-
return e
61
+
if e.imm != nil {
62
+
return Const[S](e.imm())
63
+
}
64
+
return Pending(func(s S) Fx[S, V] { return Resume(e.sus(s)) })
57
65
}
58
66
59
67
// Replace with y if x is already Halted. Otherwise x continues.
···
232
240
func Eval[V any](e Fx[Nil, V]) V {
233
241
for {
234
242
if e.res != nil {
235
-
panic("tried to evaluate halted effect. try using fx.Replace with another effect.")
243
+
panic("tried to evaluate an stopped effect. try using fx.Resume or fx.Replace on it.")
236
244
}
237
245
if e.imm != nil {
238
246
return e.imm()