rename join to flatten

Author: xieyuheng

src/monad/index.ts

@@ -4,10 +4,10 @@ import { defineGeneric } from "../generic/index.js"
 export const fmap = defineGeneric({ default: (f, ma) => f(ma) })
 
 // (M(M(A))) -> M(A)
-export const join = defineGeneric({ default: (mma) => mma })
+export const flatten = defineGeneric({ default: (mma) => mma })
 
 // (M(A), (A) -> M(B)) -> M(B)
-export const bind = (ma: any, f: (x: any) => any) => join(fmap(f, ma))
+export const bind = (ma: any, f: (x: any) => any) => flatten(fmap(f, ma))
 
 // ((A0, A1, ...) -> B) -> (M(A0), M(A1), ...) -> M(B)
 export function naryFmap(

src/monads/belief-monad.ts

@@ -1,20 +1,20 @@
 import { Belief, isBelief } from "../belief/index.js"
 import { isNothing, nothing } from "../cell/Nothing.js"
 import { defineHandler } from "../generic/index.js"
-import { bind, fmap, join } from "../monad/index.js"
+import { bind, flatten, fmap } from "../monad/index.js"
 import { isFunction } from "../utils/isFunction.js"
 import { setUnion } from "../utils/set/index.js"
 
 defineHandler(fmap, [isFunction, isBelief], (f, ma) =>
   Belief(bind(ma.value, f), ma.reasons),
 )
 
-defineHandler(join, [isBelief], (mma) => mma)
+defineHandler(flatten, [isBelief], (mma) => mma)
 defineHandler(
-  join,
+  flatten,
   [(mma) => isBelief(mma) && isNothing(mma.value)],
   (mma) => nothing,
 )
-defineHandler(join, [(mma) => isBelief(mma) && isBelief(mma.value)], (mma) =>
-  join(Belief(mma.value.value, setUnion(mma.reasons, mma.value.reasons))),
+defineHandler(flatten, [(mma) => isBelief(mma) && isBelief(mma.value)], (mma) =>
+  flatten(Belief(mma.value.value, setUnion(mma.reasons, mma.value.reasons))),
 )

src/monads/belief-system-monad.ts

@@ -1,27 +1,27 @@
 import { BeliefSystem, isBeliefSystem } from "../belief-system/index.js"
 import { Belief } from "../belief/index.js"
 import { defineHandler } from "../generic/index.js"
-import { fmap, join } from "../monad/index.js"
+import { flatten, fmap } from "../monad/index.js"
 import { isFunction } from "../utils/isFunction.js"
 
 defineHandler(fmap, [isFunction, isBeliefSystem], (f, ma: BeliefSystem<any>) =>
   BeliefSystem(ma.beliefs.map((belief) => fmap(f, belief))),
 )
 
 defineHandler(
-  join,
+  flatten,
   [
     (mma) =>
       isBeliefSystem(mma) &&
       mma.beliefs.some((belief) => isBeliefSystem(belief.value)),
   ],
   (mma: BeliefSystem<any>) =>
-    join(
+    flatten(
       BeliefSystem(
         mma.beliefs.flatMap((belief) =>
           isBeliefSystem(belief.value)
             ? belief.value.beliefs.map((innerBelief) =>
-                join(Belief(innerBelief, belief.reasons)),
+                flatten(Belief(innerBelief, belief.reasons)),
               )
             : [belief],
         ),

src/monads/nothing-monad.ts

@@ -1,8 +1,8 @@
 import { isNothing, nothing } from "../cell/Nothing.js"
 import { defineHandler } from "../generic/index.js"
-import { fmap, join } from "../monad/index.js"
+import { flatten, fmap } from "../monad/index.js"
 import { isFunction } from "../utils/isFunction.js"
 
 defineHandler(fmap, [isFunction, isNothing], (f, ma) => nothing)
 
-defineHandler(join, [isNothing], (mma) => nothing)
+defineHandler(flatten, [isNothing], (mma) => nothing)