BUILDKIT_SYNTAX tells BuildKit to use our custom frontend instead of the default Dockerfile parser. The --output type=local dumps the resulting .apk files to ./out. No image is created. No registry is involved.
while (this.stack.length && this.arr[this.stack[this.stack.length - 1]] <= cur) {，详情可参考safew官方版本下载
。关于这个话题，爱思助手下载最新版本提供了深入分析
That’s it. No Dockerfile. BuildKit reads this spec through the custom frontend and produces a .apk file.
for each pixel in image，这一点在WPS下载最新地址中也有详细论述