1 files changed, 140 insertions, 0 deletions
diff --git a/src/eval.ts b/src/eval.ts
new file mode 100644
index 0000000..4ba7033
--- /dev/null
+++ b/src/eval.ts
@@ -0,0 +1,140 @@
+import { Type } from 'ts-morph'
+import { promises as fs } from 'fs'
+import readline from 'readline';
+
+import { match } from './util';
+import { Ctx } from './types';
+
+const rl = readline.createInterface({
+  input: process.stdin,
+  output: process.stdout,
+  terminal: false
+});
+
+const readLineFromStdin = (): Promise<string> => new Promise((res) =>
+  rl.on('line', res))
+
+export const evaluateType = async (ctx: Ctx, effTyp: Type): Promise<string[]> => {
+  const name = effTyp.getSymbol()?.getName()
+
+  return match(name, {
+    DefineEffect: async () => {
+      const [nameTyp, exprTyp] = effTyp.getTypeArguments()
+      const name = nameTyp?.getLiteralValue() as string
+      const exprStr = exprTyp?.getLiteralValue() as string
+
+      ctx.addCustomEffect(name, exprStr)
+      return []
+    },
+
+    Print: async () => {
+      console.log(...effTyp.getTypeArguments().map(ctx.typeToString));
+      return []
+    },
+
+    PutString: async () => {
+      const [strinTyp] = effTyp.getTypeArguments()
+      const typString = ctx.typeToString(strinTyp)
+      const string = JSON.parse(!typString.startsWith('"') ? `"${typString}"` : typString)
+      process.stdout.write(string);
+      return []
+    },
+
+    Debug: async () => {
+      const [labelTyp, valueTyp] = effTyp.getTypeArguments()
+      const label = JSON.parse(ctx.typeToString(labelTyp))
+      const value = ctx.typeToString(valueTyp)
+      console.log(label, value)
+      const [resultKey, _] = ctx.createResult(JSON.stringify(value))
+      return [resultKey]
+    },
+
+    ReadFile: async () => {
+      const [pathTyp] = effTyp.getTypeArguments()
+      const filePath = JSON.parse(ctx.typeToString(pathTyp))
+      const contents = await fs.readFile(filePath, 'utf-8')
+      const [resultKey, _] = ctx.createResult(JSON.stringify(contents))
+      return [resultKey]
+    },
+
+    WriteFile: async () => {
+      const [pathTyp, contentsTyp] = effTyp.getTypeArguments()
+      const filePath = JSON.parse(ctx.typeToString(pathTyp))
+      const contents = JSON.parse(ctx.typeToString(contentsTyp))
+      await fs.writeFile(filePath, contents)
+      return []
+    },
+
+    Bind: async () => {
+      const [inputTyp, chainToKind] = effTyp.getTypeArguments()
+      const [resultKey] = inputTyp ? await evaluateType(ctx, inputTyp) : []
+
+      const [_, compNode] = ctx.createResult(
+        `(${ctx.typeToString(chainToKind)} & { input: (${ctx.getResultExpr(resultKey)})['output'] })['return']`)
+      // TODO: Avoid using getTypeAtLocation?
+      const compTyp = compNode?.getType().getProperty('output')?.getTypeAtLocation(ctx.entryPoint)
+
+      return compTyp ? await evaluateType(ctx, compTyp) : []
+    },
+
+    GetEnv: async () => {
+      const [envTyp] = effTyp.getTypeArguments()
+      const envName = JSON.parse(ctx.typeToString(envTyp))
+      const [resultKey, _] = ctx.createResult(`${JSON.stringify(process.env[envName] ?? '')}`)
+      return [resultKey]
+    },
+
+    GetArgs: async () => {
+      const [resultKey, _] = ctx.createResult(`${JSON.stringify(process.argv.slice(2))}`)
+      return [resultKey]
+    },
+
+    ReadLine: async () => {
+      const line = await readLineFromStdin()
+      const [resultKey, _] = ctx.createResult(`${JSON.stringify(line)}`)
+      return [resultKey]
+    },
+
+    JsExpr: async () => {
+      const [exprTyp] = effTyp.getTypeArguments()
+      const exprStr = JSON.parse(ctx.typeToString(exprTyp))
+      const result = eval(`JSON.stringify(${exprStr})`)
+      const [resultKey, _] = ctx.createResult(`${result}`)
+      return [resultKey]
+    },
+
+    Seq: async () => {
+      const [effectTyps] = effTyp.getTypeArguments()
+      const effectResults = await evalList(ctx, effectTyps?.getTupleElements() ?? [])
+      const [resultKey, _] = ctx.createResult(`[
+        ${effectResults.map(ctx.getResultExpr).join(', ')}
+      ]`)
+      return [resultKey]
+    },
+
+    Do: async () => {
+      const [effectTyps] = effTyp.getTypeArguments()
+      const effectResults = await evalList(ctx, effectTyps?.getTupleElements() ?? [])
+      const lastResKey = effectResults[effectResults.length - 1]
+      const [resultKey, _] = ctx.createResult(`${ctx.getResultExpr(lastResKey)}['output']`)
+      return [resultKey]
+    },
+
+    _: async () => {
+      if (name && ctx.hasCustomEffect(name)) {
+        return ctx.runCustomEffect(name, effTyp.getTypeArguments())
+      }
+
+      console.log(`${name} result effect is unhandled`)
+      return []
+    },
+  })
+}
+
+export const evalList = async (ctx: Ctx, effectTyps: Type[]) => {
+  const effectResults: string[] = []
+  for (const item of effectTyps ?? []) {
+    effectResults.push(...(await evaluateType(ctx, item)))
+  }
+  return effectResults
+}