[cps] [refactoring] rename ProblemSpace to Space

TODO.md

@@ -1,6 +1,8 @@
-[cps] `problem-solver/` -- 用单个的 `Solver` class 来实现 -- 而不是 `ProblemSpace` + `Searching`
+[cps] [refactoring] rename ProblemPath to Path
 
-[cps] [problem-space] [subway] `SubwayProblemSpace` & `createSubwayProblemSpace`
+[cps] `solver/` -- 用单个的 `Solver` class 来实现 -- 而不是 `Space` + `Searching`
+
+[cps] [problem-space] [subway] `SubwaySpace` & `createSubwaySpace`
 
 - Problem = Station
 

docs/diary/2024-08-25-space-and-searching-vs-solver.md

@@ -6,8 +6,40 @@ date: 2024-08-25
 在实现 Problem Space Model 的时候，
 发现有两种组织 class 的方式：
 
-- 一、用单个的 `Solver` class 来实现。
-- 二、将 `Solver` 分解为 `ProblemSpace` + `Searching` 这两个 class 来实现。
+一、用单个的 `Solver` class 来实现。
+
+```typescript
+export type Solver<Problem, Branch> = {
+  name: string
+  problemIsSolved: (problem: Problem) => boolean
+  problemEqual: (left: Problem, right: Problem) => boolean
+  validBranches: (problem: Problem) => Array<Branch>
+  branchApply: (branch: Branch, problem: Problem) => Problem
+
+  problem: Problem
+  queue: Array<ProblemPath<Problem, Branch>>
+  solved: Array<ProblemPath<Problem, Branch>>
+}
+```
+
+二、将 `Solver` 分解为 `Space` + `Searching` 这两个 class 来实现。
+
+```typescript
+export type Space<Problem, Branch> = {
+  name: string
+  problemIsSolved: (problem: Problem) => boolean
+  problemEqual: (left: Problem, right: Problem) => boolean
+  validBranches: (problem: Problem) => Array<Branch>
+  branchApply: (branch: Branch, problem: Problem) => Problem
+}
+
+export type Searching<Problem, Branch> = {
+  space: Space<Problem, Branch>
+  problem: Problem
+  queue: Array<ProblemPath<Problem, Branch>>
+  solved: Array<ProblemPath<Problem, Branch>>
+}
+```
 
 对比二者的 API：
 
@@ -17,14 +49,20 @@ searching.space.problemIsSolved(path.current)
 ```
 
 一个 `Solver` class 的 API 更简单。
-但是实际上描述一个问题空间的 interface 是 `ProblemSpace`，
+但是实际上描述一个问题空间的 interface 是 `Space`，
 而 `Searching` 是 search 运行是所需要的搜索状态。
 
-书中的实现是只有 `ProblemSpace`，
+书中的实现是只有 `Space`，
 search 函数的搜索状态没有作为一个 `Searching` class 暴露出来。
 
 我将同时做出这两种风格的实现，作为一个 API 设计的练习。
 
 我怀疑，Space + Searching 是更好的设计，
 但是 Space 的所有 interface 好像都是为了 search 来服务的，
 所以也许 Space 和 Space 应该合并为 Solver。
+
+另外，`Space<Problem, Branch>`
+是否应该改为 `Space<Node, Edge>`？
+此时可以说 `Space` 并不只是为 search 服务的，
+而是代表了一个更一般的图论意义上的空间。
+这样空间和搜索两部分 interface 看起来就相互独立了。

src/cps/solver/Solver.ts

@@ -0,0 +1,11 @@
+// export type Solver<Problem, Branch> = {
+//   name: string
+//   problemIsSolved: (problem: Problem) => boolean
+//   problemEqual: (left: Problem, right: Problem) => boolean
+//   validBranches: (problem: Problem) => Array<Branch>
+//   branchApply: (branch: Branch, problem: Problem) => Problem
+
+//   problem: Problem
+//   queue: Array<ProblemPath<Problem, Branch>>
+//   solved: Array<ProblemPath<Problem, Branch>>
+// }

src/cps/problem-space/ProblemPath.ts → src/cps/space/ProblemPath.ts

@@ -1,4 +1,4 @@
-import { type ProblemSpace } from "./ProblemSpace.js"
+import { type Space } from "./Space.js"
 
 // 假设我们用 (p) 来表示 Problem，用 [b] 来表示 Branch，
 // 那么形如 (p0) -> [b0] -> (p1) -> [b1] -> (p2) 的 Path，
@@ -7,13 +7,13 @@ import { type ProblemSpace } from "./ProblemSpace.js"
 // - current: p2
 
 export type ProblemPath<Problem, Branch> = {
-  space: ProblemSpace<Problem, Branch>
+  space: Space<Problem, Branch>
   prefix: Array<[Problem, Branch]>
   current: Problem
 }
 
 export function initialProblemPath<Problem, Branch>(
-  space: ProblemSpace<Problem, Branch>,
+  space: Space<Problem, Branch>,
   problem: Problem,
 ): ProblemPath<Problem, Branch> {
   return {

src/cps/problem-space/Searching.ts → src/cps/space/Searching.ts

@@ -1,15 +1,15 @@
 import { type ProblemPath } from "./ProblemPath.js"
-import { type ProblemSpace } from "./ProblemSpace.js"
+import { type Space } from "./Space.js"
 
 export type Searching<Problem, Branch> = {
-  space: ProblemSpace<Problem, Branch>
+  space: Space<Problem, Branch>
   problem: Problem
   queue: Array<ProblemPath<Problem, Branch>>
   solved: Array<ProblemPath<Problem, Branch>>
 }
 
 export function createSearching<Problem, Branch>(
-  space: ProblemSpace<Problem, Branch>,
+  space: Space<Problem, Branch>,
   problem: Problem,
 ): Searching<Problem, Branch> {
   return {

src/cps/problem-space/ProblemSpace.ts → src/cps/space/Space.ts

@@ -1,4 +1,4 @@
-export type ProblemSpace<Problem, Branch> = {
+export type Space<Problem, Branch> = {
   name: string
   problemIsSolved: (problem: Problem) => boolean
   problemEqual: (left: Problem, right: Problem) => boolean

src/cps/problem-space/index.ts → src/cps/space/index.ts

@@ -1,4 +1,4 @@
 export * from "./breadthFirstExplore.js"
 export * from "./ProblemPath.js"
-export * from "./ProblemSpace.js"
+export * from "./Space.js"
 export * from "./Searching.js"