In October 2022, Shopify released ShopifyQL Notebooks, a first-party app that lets merchants analyze their shop data to make better decisions. It puts the power of ShopifyQL into merchants’ hands with a guided code editing experience. In order to provide a first-class editing experience, we turned to CodeMirror, a code editor framework built for the web. Out of the box, CodeMirror didn’t have support for ShopifyQL–here’s how we built it. ShopifyQL Everywhere ShopifyQL is an accessible, commerce-focused querying language used on both the client and server. The language is defined by an ANTLR grammar and is used to generate code for multiple targets (currently, Go and Typescript). This lets us share the same grammar definition between both the client and server despite differences in runtime language. As an added benefit, we have types written in Protobuf so that types can be shared between targets as well. All the ShopifyQL language features on the front end are encapsulated into a typescript language server, which is built on top of the ANTLR typescript target. It conforms to Microsoft's language server protocol (LSP) in order to keep a clear separation of concerns between the language server and a code editor. LSP defines the shape of common language features like tokenization, parsing, completion, hover tooltips, and linting. When code editors and language servers both conform to LSP, they become interoperable because they speak a common language. For more information about LSP, read the VSCode Language Server Extension Guide. Connecting The ShopifyQL Language Server To CodeMirror CodeMirror has its own grammar & parser engine called Lezer. Lezer is used within CodeMirror to generate parse trees, and those trees power many of the editor features. Lezer has support for common languages, but no Lezer grammar exists for ShopifyQL. Lezer also doesn’t conform to LSP. Because ShopifyQL’s grammar and language server had already been written in ANTLR, it didn’t make sense to rewrite what we had as a Lezer grammar. Instead, we
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