[lang1] 支持 (import)

TODO.md

@@ -1,4 +1,3 @@
-[lang1] 支持 `(import)`
 [lang1] test `(import)`
 
 > [lang0] 支持直接递归函数与相互递归函数，不能判断等价的地方就不判断。

src/lang1/mod/index.ts

@@ -1,4 +1,5 @@
 export * from "./Mod.js"
+export * from "./modResolve.js"
 export * from "./createMod.js"
 export * from "./modDefine.js"
 export * from "./modFind.js"

src/lang1/mod/modResolve.ts

@@ -0,0 +1,5 @@
+import { type Mod } from "./index.js"
+
+export function modResolve(mod: Mod, href: string): URL {
+  return new URL(href, mod.url)
+}

src/lang1/run/execute.ts

@@ -2,6 +2,7 @@ import { formatExp } from "../format/formatExp.js"
 import { modDefine, type Mod } from "../mod/index.js"
 import { reduce } from "../reduce/reduce.js"
 import { type Stmt } from "../stmt/Stmt.js"
+import { importOne } from "./importOne.js"
 
 export function execute(mod: Mod, stmt: Stmt): null | string {
   switch (stmt["@kind"]) {
@@ -20,7 +21,11 @@ export function execute(mod: Mod, stmt: Stmt): null | string {
     }
 
     case "Import": {
-      throw new Error("TODO")
+      for (const entry of stmt.entries) {
+        importOne(mod, stmt.path, entry)
+      }
+
+      return null
     }
   }
 }

src/lang1/run/importOne.ts

@@ -0,0 +1,29 @@
+import { modDefine, modFind, modResolve } from "../mod/index.js"
+import type { Mod } from "../mod/Mod.js"
+import type { ImportEntry } from "../stmt/Stmt.js"
+import { executeMod } from "./executeMod.js"
+
+export function importOne(mod: Mod, path: string, entry: ImportEntry): void {
+  const url = modResolve(mod, path)
+  if (url.href === mod.url.href) {
+    throw new Error(`I can not circular import: ${path}`)
+  }
+
+  const found = mod.loadedMods.get(url.href)
+  if (found === undefined) {
+    throw new Error(`Mod is not loaded: ${path}`)
+  }
+
+  executeMod(found.mod)
+
+  const { name, rename } = entry
+
+  const def = modFind(found.mod, name)
+  if (def === undefined) {
+    throw new Error(
+      `I can not import undefined name: ${name}, from path: ${path}`,
+    )
+  }
+
+  modDefine(mod, rename || name, def)
+}