DrummerはどうやってユーザーのScriptを実行しているのか
code:scripting.js
function runScriptText(scriptText, callback) {
if (callback == null) {
callback = function () {};
}
function visitCodeTree (theTree, visit) {
var stack = new Array ();
function doVisit (node) { //depth-first traversal
for (var x in node) {
if (typeof node x == "object") { stack.push (node);
stack.pop ();
}
}
if (node != null) {
visit (node, stack);
}
}
doVisit (theTree);
}
function fixSpecialFunctionCalls (theTree) {
visitCodeTree (theTree, function (node, stack) {
if (node.type == "FunctionDeclaration" || node.type == 'FunctionExpression') {
node.async = true;
}
if (node.type == "CallExpression" && node.callee !== undefined) {
var nodecopy = Object.assign(new Object (), node);
for (var x in node) {
}
node.type = "AwaitExpression";
node.argument = nodecopy;
}
return (undefined); // don't replace
});
}
function preprocessScript(scriptText) {
var scriptBody = '', tokens, i, info;
var code = acorn.parse (scriptText, {ecmaVersion: 2020});
fixSpecialFunctionCalls (code);
scriptBody = escodegen.generate (code);
return "(async function () {" + scriptBody + "})()";
}
(async function () {
var processedScriptText = preprocessScript (scriptText);
console.log ("runScriptText: processedScriptText == " + processedScriptText);
var scriptVal = eval (processedScriptText);
return (scriptVal);
})()
.then(function (response) {
callback(null, response);
})
.catch(function (error) {
callback(error);
});
}
このrunScriptText()の第一引き数にコードの文字列を与えると、それが実行される。
async function は非同期関数
eval()がコードを実行（評価）している
実際の使われ方
code:code.js
runScriptText (scripttext, function (err, value) {
if (err) {
alertDialog ("Error running script: " + err.message + ".");
}
});
}