Haxe for javascript without global namespace pollution?
This question only applies to Haxe version < 2.10
I've known about haxe for a while, but never really played with it until yesterday. Being curious, I decided to port showdown.js, a javascript port of markdown.pl, to haxe. This was pretty straightforward, and the javascript it generates seems to run fine ( edit: If you want to see it in action, check it out here).
However, I noticed that the generated code dumps a ton of stuff in the global namespace... and what's worse, it does it by assigning values to undeclared identifiers without using the var keyword, so they're global even if you wrap the whole thing with a closure.
For example...
if(typeof js=='undefined') js = {}
...
Hash = function(p) { if( p === $_ ) return; {
...
EReg = function(r,opt) { if( r === $_ ) return; {
...
I managed to clean most of that up with sed, but I'm also bothered by stuff like this:
{
String.prototype.__class__ = String;
String.__name__ = ["String"];
Array.prototype.__class__ = Array;
Array.__name__ = ["Array"];
Int = { __name__ : ["Int"]}
Dynamic = { __name__ : ["Dynamic"]}
Float = Number;
Float.__name__ = ["Float"];
Bool = { __ename__ : ["Bool"]}
Class = { __name__ : ["Class"]}
Enum = { }
Void = { __ename__ : ["Void"]}
}
{
Math.__name__ = ["Math"];
Math.NaN = Number["NaN"];
Math.NEGATIVE_INFINITY = Number["NEGATIVE_INFINITY"];
Math.POSITIVE_INFINITY = Number["POSITIVE_INFINITY"];
Math.isFinite = function(i) {
return isFinite(i);
}
Math.isNaN = function(i) {
return isNaN(i);
}
}
This is some pretty unsavory javascript.
Questions
Is there a fork or clone of haxe somewhere that doesn't pollute globals? Is it worth it to modify the haxe source to get what I want, or has someone already solved this? Googling hasn't turned up much. I'm open to any suggestions. Meanwhile, I'm dying to see what kind of PHP code this thing's going to produce... :D
Answers?
Here are some of the ideas I've tried:
postprocessing
Here's my humble build script; it does a pretty good job of stripping stuff out, but it doesn't catch everything. I'm hesitant to remove the modifications to the built-in constructor prototypes; I'm sure that would break things. Fixing everything might be a bit of a task, and I don't want to start on it if someone's already done the work...
haxe -cp ~/Projects/wmd-new -main Markdown -js markdown.js
echo "this.Markdown=(function(){ var $closure, Float;" > markdown.clean.js;
sed "s/^if(typeof js=='undefined') js = {}$/if(typeof js=='undefined') var js = {};/g ;
s/^([ x09]*)([$_a-zA-Z0-9]* = ({|function))/1var 2/g ;
/^[ x09]*(else )?null;$/d ;
" markdown.js >> markdown.clean.js
echo "return Markdown}());" >> markdown.clean.js;
java -jar closure/compiler.jar --js markdown.clean.js
--compilation_level SIMPLE_OPTIMIZATIONS
> markdown.cc.js
--js-namespace switch saves the day
Thanks to Dean Burge for pointing out the namespace switch. This pretty much solved my problem, with a minor bit of help. Here's my current build script. I think this catches all the global variables...
NS=N$
haxe -cp ~/Projects/wmd-new -main Markdown --js-namespace $NS -js markdown.js
# export our function and declare some vars
echo "this.markdown=(function(){var $_,$Main,$closure,$estr,js,"$NS"" > markdown.clean.js;
# strip silly lines containing "null;" or "else null;"
sed "/^[ x09]*(else )?null;$/d ;" markdown.js >> markdown.clean.js
# finish the closure
echo "return "$NS".Markdown.makeHtml}());" >> markdown.clean.js;
我使用编译器上的命名空间开关来清理这些全局根类型。
Haxe is not meant to be used for writing an isolated reusable component in a javascript web application. This is evidenced by the fact that the compiler emits standard library for every goddamn compilation. Most optimal use of javascript target is to write an application entirely in haxe and call external stuff using untyped blocks hoping it won't break anything. You should treat haxe output like a flash clip, oblivious to the environment it runs in, assumes it is the only thing running.
Or you might try wrapping the code with a with() block.
这里有一个命名空间（实验）haxe编译器http://github.com/webr3/haxe
链接地址: http://www.djcxy.com/p/18330.html