class Test
def initialize
end
def crash
print x
end
end
Test.new.crash
显然,此代码段将在第8行崩溃。如果您使用Opal解析此代码,您将获得此编译代码:
/* Generated by Opal 0.8.0.beta1 */
(function(Opal) {
Opal.dynamic_require_severity = "error";
var self = Opal.top, $scope = Opal, nil = Opal.nil, $breaker = Opal.breaker, $slice = Opal.slice, $klass = Opal.klass;
Opal.add_stubs(['$print', '$x', '$crash', '$new']);
(function($base, $super) {
function $Test(){};
var self = $Test = $klass($base, $super, 'Test', $Test);
var def = self.$$proto, $scope = self.$$scope;
def.$initialize = function() {
var self = this;
return nil;
};
return (def.$crash = function() {
var self = this;
return self.$print(self.$x());
}, nil) && 'crash';
})(self, null);
return $scope.get('Test').$new().$crash();
})(Opal);
当然它会抛出相同的错误。
但是,有没有办法确定此错误来自的 Ruby 行?
我可以看到这个问题:Is there a way to show the Ruby line numbers in javascript generated by Opal,但我不明白答案:它引导我https://github.com/opal/opal/tree/0-6-stable/examples/rack而且我不确定我应该在寻找什么在或做。
当我运行我的javascript时,我有一个加载index.html
和opal.min.js
的{{1}}文件,最后我在opal-parser.min.js
标记中编译了我编译的Ruby-Javascript代码
答案 0 :(得分:3)
Opal有source map support,以促进这种源级别的调试。我不会详细介绍有关源图,但HTML5Rocks有great article深入介绍该主题。
这是用Opal设置的最小样板:
让index.rb
成为我们的源文件:
class Test
def initialize
end
def crash
print x
end
end
Test.new.crash
由于您不想使用大量无用的实用程序,因此我们直接使用Opal API。创建一个文件builder.rb
,它将编译上面的文件:
require 'opal'
Opal::Processor.source_map_enabled = true
Opal.append_path "."
builder = Opal::Builder.new.build('index')
# Write the output file containing a referece to sourcemap
# which we generate below : this will help the browser locate the
# sourcemap. Note that we are generating sourcemap for only code and not
# the entire Opal corelib.
#
File.binwrite "build.js", "#{builder.to_s}\n//# sourceMappingURL=build.js.map"
File.binwrite "build.js.map", builder.source_map.to_s
File.binwrite "opal_lib.js", Opal::Builder.build('opal_lib')
同时创建仅包含以下内容的opal_lib.rb
文件:
require 'opal'
最后创建一个index.html
,允许我们在浏览器中运行脚本。
<!DOCTYPE html>
<html>
<head>
<script src="opal_lib.js"></script>
<script src="build.js"></script>
</head>
<body>
</body>
</html>
现在要实际编译你的文件,运行:
ruby builder.rb
这将生成已编译的javascript文件opal_lib.js
和build.js
,这些文件由我们的index.html
文件引用。现在只需在浏览器中打开index.html
即可。您将获得完整的调用堆栈和源视图:
源文件的行号可用:
作为使用浏览器的替代方法,您也可以将Node.js用于相同目的。这需要您安装Node.js
和npm
。您还需要安装npm模块source-map-support
npm install source-map-support
现在您可以打开节点repl并输入以下内容:
require('source-map-support').install();
require('./opal_lib');
require('./build');
您将获得具有正确源代码行的堆栈跟踪:
/home/gaurav/Workspace/opal-playground/opal_lib.js:4436
Error.captureStackTrace(err);
^
NoMethodError: undefined method `x' for #<Test:0x102>
at OpalClass.$new (/home/gaurav/Workspace/opal-playground/opal_lib.js:4436:15)
at OpalClass.$exception (/home/gaurav/Workspace/opal-playground/opal_lib.js:4454:31)
at $Test.$raise (/home/gaurav/Workspace/opal-playground/opal_lib.js:4204:31)
at $Test.Opal.defn.TMP_1 (/home/gaurav/Workspace/opal-playground/opal_lib.js:3032:19)
at $Test.method_missing_stub [as $x] (/home/gaurav/Workspace/opal-playground/opal_lib.js:886:35)
at $Test.$crash (/home/gaurav/Workspace/opal-playground/index.rb:8:11)
at /home/gaurav/Workspace/opal-playground/index.rb:13:10
at Object.<anonymous> (/home/gaurav/Workspace/opal-playground/index.rb:13:10)
at Module._compile (module.js:435:26)
at Object.Module._extensions..js (module.js:442:10)
我建议您使用bundler进行gem管理。以下是获取Opal master的Gemfile
:
source 'http://production.cf.rubygems.org'
gem 'opal', github: 'opal/opal'
要编译,您必须运行:
bundle install
bundle exec ruby builder.rb
其他人提到的链轮集成/机架集成在下面使用相同的API,抽象出管道。
更新
由于我们在堆栈中有正确的行号,因此可以通过编程方式解析堆栈并将此行号提取到变量中:
require('./opal_lib');
require('source-map-support').install();
var $e = null;
try {
require('./build');
} catch (e) {
$e = e;
}
var lines = e.split('\n').map(function(line){ return line.match(/^.*\((\S+):(\d+):(\d+)\)/) })
var first_source_line;
for (var i = 0; i < lines.length ; i++) {
var match = lines[i];
if (match == null) continue;
if (match[1].match(/index.rb$/) {
first_source_line = match;
break;
}
}
var line_number;
if (first_source_line) line_number = first_source_line[2] // ==> 8
当然你也可以做ruby(但是如果你在浏览器中运行它,你也必须在这里包含source-map-support):
class Test
def initialize
end
def crash
print x
end
end
line_num = nil
begin
Test.new.crash
rescue => e
if line = e.backtrace.map{|line| line.match(/^.*\((\S+):(\d+):(\d+)\)/) }.compact.find{|match| match[1] =~ /index.rb$/ }
line_num = line[2]
end
end
puts "line_num => #{line_num}" # ==> 8