> Arjun Guha, Claudio Saftoiu and Shriram Krishnamurthi have a recent paper on > the topic: > > http://www.cs.brown.edu/~sk/Publications/Papers/Published/gsk-essence-javascript/ > Having had some experience with this question myself, let me just say that > while formalization is > appealing, it's a very subtle and time-consuming task.
I don't agree with this. Two of us formalized, implemented, and tested that paper in a month. That is hardly time-consuming, and it's not very subtle since we have test suites to test our formalization. We haven't perfectly matched the *entire* spec. (e.g. we mapped JS regexps to regexps in Scheme). But, I believe we got a covered a good portion of ES3 (see section 3 of the paper). > That includes more rigorous approaches like operational semantics Don't try to build a semantics for the entire language. Instead, build a semantics for the "essentials" (i.e. objects and functions) and write a function that elaborates all the details of language into the semantics. > Math gives you more wiggle-room, but it's still finicky and much slower going > than code. You do not have to choose between "math" and "code". You can use both as appropriate. If you look at the paper, think of LambdaJS as the essential math, and desugaring as code for the remaining details. And > even most research languages don't have fully formalized semantics. [ Standard ML is about the only > one I know of that is 100% formalized. Don't tell me Scheme is I don't think anyone claims that it is. > (I'm not saying improving the spec language is a bad idea, just trying to > spell out some of the challenges.) Btw, Joe Politz (student at Brown) is currently formalizing ES5 following the approach Claudiu and I used for current-JavaScript. He's striving to conform to the conformance suite and has already made some progress. The project is on Github, as usual: http://github.com/arjunguha/ML-LambdaJS It's the LambdaJS approach: a semantics for the essentials, which lets you write precisely write down the algorithms in the spec: http://github.com/arjunguha/ML-LambdaJS/blob/master/data/es5-lib.es5 Arjun _______________________________________________ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss
