feat(cli): add cli for power-doctest

bin/cmd.js

@@ -0,0 +1,14 @@
+#!/usr/bin/env node
+var convertCode = require('../').convertCode;
+var concat = require('concat-stream');
+var fs = require('fs');
+var path = require("path");
+var file = process.argv[2];
+var input = file && file !== '-'
+        ? fs.createReadStream(process.argv[2])
+        : process.stdin
+    ;
+input.pipe(concat(function (buf) {
+    var filePath = path.join(process.cwd(), file);
+    console.log(convertCode(buf.toString('utf8'), filePath));
+}));

src/power-doctest.js

@@ -4,6 +4,15 @@ import {toAssertFromAST} from "comment-to-assert"
 import {injectAssertModule} from "./inject-assert"
 import empower from "empower"
 import assert from "assert"
+import ASTSource from "ast-source"
+export function convertCode(code, filePath) {
+    var source = new ASTSource(code, {
+        filePath: filePath,
+        disableSourceMap: typeof filePath === "undefined"
+    });
+    var output = source.transform(convertAST).output();
+    return output.codeWithMap;
+}
 
 export function convertAST(AST) {
     var empowerOptions = {modifyMessageOnRethrow: true, saveContextOnRethrow: true};