oeiuwq.com
An Algebraic Effect System for Golang.
Stop
+14
-15
+1
-1
abort/result.go
+1
-1
abort/result.go
···
13
13
var err Result[V, E]
14
14
var abortFn AbortFn[E] = func(e E) fx.FxNil {
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15
err = failure[V](e)
16
-
return fx.Halt[fx.Nil, fx.Nil]()
16
+
return fx.Stop[fx.Nil, fx.Nil]()
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17
}
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18
succeeded := fx.Map(fx.ProvideLeft(e, abortFn), success[V, E])
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failed := func() fx.FxPure[Result[V, E]] { return fx.Pure(err) }
+13
-14
fx.go
+13
-14
fx.go
···
3
3
type Fx[S, V any] struct {
4
4
imm func() V
5
5
sus func(S) Fx[S, V]
6
-
hlt func()
6
+
stp func()
7
7
}
8
8
9
9
type FxPure[V any] = Fx[Nil, V]
···
29
29
30
30
func Ctx[V any]() Fx[V, V] { return Func(identity[V]) }
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31
32
-
// An effect that will never be continued.
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-
func Halt[S, V any]() Fx[S, V] { return Fx[S, V]{hlt: func() {}} }
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+
func Stop[S, V any]() Fx[S, V] { return Fx[S, V]{stp: func() {}} }
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33
35
-
// Replace with y if x is already Halted. Otherwise x continues.
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+
// Replace with y if x is already stopped. Otherwise x continues.
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func Replace[S, V any](y func() Fx[S, V]) func(Fx[S, V]) Fx[S, V] {
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36
return func(x Fx[S, V]) Fx[S, V] {
38
-
if x.hlt != nil {
37
+
if x.stp != nil {
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38
return y()
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39
}
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40
if x.imm != nil {
···
48
47
// Continue an effect by transforming its immediate value into another effect.
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func Cont[T, U, S, V any](cmap func(T) S, fmap func(V) Fx[T, U]) func(Fx[S, V]) Fx[T, U] {
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49
return func(e Fx[S, V]) Fx[T, U] {
51
-
if e.hlt != nil {
52
-
return Halt[T, U]()
50
+
if e.stp != nil {
51
+
return Stop[T, U]()
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52
}
54
53
if e.imm != nil {
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54
return fmap(e.imm())
···
80
79
81
80
func ContraMap[V, S, R any](f func(R) S) func(Fx[S, V]) Fx[R, V] {
82
81
return func(e Fx[S, V]) Fx[R, V] {
83
-
if e.hlt != nil {
84
-
return Halt[R, V]()
82
+
if e.stp != nil {
83
+
return Stop[R, V]()
85
84
}
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85
if e.imm != nil {
87
86
return Const[R](e.imm())
···
161
160
}
162
161
163
162
func ProvideLeft[A, B, V any](e Fx[And[A, B], V], a A) Fx[B, V] {
164
-
if e.hlt != nil {
165
-
return Halt[B, V]()
163
+
if e.stp != nil {
164
+
return Stop[B, V]()
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165
}
167
166
if e.imm != nil {
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167
return Const[B](e.imm())
···
171
170
var ab And[A, B] = func() (A, B) { return a, b }
172
171
for {
173
172
e = e.sus(ab)
174
-
if e.hlt != nil {
175
-
return Halt[B, V]()
173
+
if e.stp != nil {
174
+
return Stop[B, V]()
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175
}
177
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if e.imm != nil {
178
177
return Const[B](e.imm())
···
199
198
200
199
func Eval[V any](e Fx[Nil, V]) V {
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200
for {
202
-
if e.hlt != nil {
201
+
if e.stp != nil {
203
202
panic("tried to evaluate halted effect. try using fx.Replace with another effect.")
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203
}
205
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if e.imm != nil {