Path: csiph.com!weretis.net!feeder6.news.weretis.net!news.misty.com!news.iecc.com!.POSTED.news.iecc.com!nerds-end From: "Kartik Agaram" Newsgroups: comp.compilers Subject: Re: How do you create a grammar for a multi-language language? Date: Sat, 05 Mar 2022 16:55:48 -0800 Organization: Compilers Central Lines: 36 Sender: news@iecc.com Approved: comp.compilers@iecc.com Message-ID: <22-03-007@comp.compilers> References: <22-03-004@comp.compilers> <22-03-006@comp.compilers> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Injection-Info: gal.iecc.com; posting-host="news.iecc.com:2001:470:1f07:1126:0:676f:7373:6970"; logging-data="68525"; mail-complaints-to="abuse@iecc.com" Keywords: parse, design Posted-Date: 05 Mar 2022 20:11:57 EST X-submission-address: compilers@iecc.com X-moderator-address: compilers-request@iecc.com X-FAQ-and-archives: http://compilers.iecc.com In-Reply-To: <22-03-006@comp.compilers> Xref: csiph.com comp.compilers:2912 > I am working with a team to develop a new language and our current thinking is > that the language will use the XPath language for navigating through documents > and the CSS language for expressing sets of match/action pairs. That feels like a much more tractable problem. Don't even think of it as a multi-language language. It's a language you're designing (so you have lots of room for maneuver) around XPath. > This idea of multi-language languages is very common within the XML community. > For example, the XSLT language uses (hosts) the XPath language. Here is an > excerpt to illustrate: > > select="/Bookstore/Book[1]/Title" > > The expression /Bookstore/Book[1]/Title is an XPath expression, the other > parts are XSLT. So, the format of the select statement is: > > select="XPath" > > See how XSLT hosts XPath? That is, one language (XSLT) is using another > language (XPath). Yeah, putting a second language inside the string literals of the first is a very common approach. All the tooling for the outer language can remain oblivious of the second. You don't even need to design a new language, this approach works with any existing one, and you can focus on implementing a library to process XPath. If you do want to design another language, however, you can make things a lot nicer. For example: - any URL is a valid literal in the Red programming language: https://github.com/red/docs/blob/master/en/datatypes.adoc - the JSX extension of JavaScript used in the React framework permits component literals that look a lot like some sort of markup language: https://reactjs.org/docs/introducing-jsx.html Kartik http://akkartik.name/about