@liquify/specs

This package is available on the npm registry for modules consumed by the Liquify parser and text editor extension/plugin but it also exists as point of reference for different Liquid variations and can be appropriated into projects outside of Liquify. At its core, the module provides lexical, parse and feature capabilities for the Liquify Liquid Language Server and Liquid Language Parser.

What?

In the context of the Liquid Language Server, these specifications are just data references that describe Liquid and HTML syntax. These are not quite parsing grammars and despite the name, they are not official specifications.

Why?

Liquid is a basic template language that is consumer facing. When building the Liquify (Liquid) parser one of my main goals was to standardize all variations of the language but such a task is impossible due to the fact Liquid is a template language and can exist in a customized formats. The resulting solution was to produce a simple, extensible and integrated solution for interfacing with the parser and language server. The result is Liquid Language Specifications.

Supported

The modules provides raw data references for the following:

• HTML
• Liquid Standard
• Liquid Shopify

TODO

The following Liquid variations are scheduled to be mapped.

• Liquid 11ty
• Liquid Jekyll

Install

pnpm add @liquify/specs

Usage

The module provides a informal Query Engine that interfaces with both HTML and Liquid specifications. The module enables the Liquify Liquid Language Server and Liquid Language Parser to interact, traverse and query raw data at different points. This allows for capabilities like code completions, validations (linting) and signatures to be provided. The query engine is typically used by the parser and each time a tag, object or filter is encountered during traversal operations we query its specification reference and from here the scanner (or language server) will act accordingly.

Read More about queries

Data (liquid and html5)

We can access the specifications via 2 named exports, html5 and liquid. Both exports are objects and provide us direct access to the data (ie: specifications). These data exports are merely convenience exports that expose the specifications used by the providers (p) and queries (q) exports that are at the core of traversal.

import { html5, liquid } from '@liquify/specs';

// LIQUID STANDARD

liquid.standard;
liquid.standard.tags;
liquid.standard.filters;

// LIQUID SHOPIFY

liquid.shopify;
liquid.shopify.tags;
liquid.shopify.filters;
liquid.shopify.objects;

// LIQUID JEKYLL

liquid.jekyll;
liquid.jekyll.tags;
liquid.jekyll.filters;
liquid.jekyll.objects;

// HTML5

html5.tags;
html5.attributes;
html5.values;

State ($)

The $ state named export holds in-stream data reference to the specification values in traversal. The references will change and update in accordance with query operations carried out via q queries. The states are Read Only getters and their records will be reset to undefined or NaN each time parsing begins on new tokens (tags, objects or filters).

You cannot augment state references, they are readonly.

import { $ } from '@liquify/specs';

// LIQUID

$.liquid.engine;        // The current variation engine, ie: standard, shopify etc
$.liquid.tag;           // The tag object specification in traversal
$.liquid.filter;        // The filter object specification in traversal
$.liquid.object;        // The object or property object specification in traversal
$.liquid.argument;      // The tag or filter argument record in traversal
$.liquid.value;         // The current tag, filter or object value in traversal
$.liquid.separator;     // The current separator character code (if any)
$.liquid.type;          // A persisted reference to a certain type, like an object type
$.liquid.within;        // An enum number value informing upon the within status
$.liquid.variable;      // A string[] list value which holds reference to an assigned value
$.liquid.files;         // Map reference which maintain file specific data.

// HTML5

$.html5.tag;           // The tag object specification in traversal
$.html5.attribute;     // The attribute specification in traversal
$.html5.value;         // The attribute value specification in traversal

Query (q)

The q query export allows us to navigate through specifications. These methods are typically used by the Liquify parser and will augment the state $ references during lexical analysis. Almost all queries and operations update state $ records.

import { q } from '@liquify/specs';

// LISTS

q.getTags(engine?: Engine): string[]
q.getFilters(engine?: Engine): string[]
q.getObjects(engine?: Engine): string[]

// SETTERS

q.setEngine(engine: IEngine): void
q.setTag(token: string): boolean;
q.setType(type: string): boolean;
q.setFilter(token: string): boolean;
q.setObject(token: string): boolean;
q.setVariable(token: string): boolean;

// CHECKSUMS

q.hasRequires(filters: NodeFilters): boolean;
q.hasObject(name: string): boolean;
q.hasProperty(name: string): boolean;

// VALIDATORS

q.isError(err: QueryError): boolean;
q.isObjectType(type: number): boolean;
q.isOptional(from: number): boolean;
q.isAllowed(prop: string): boolean;
q.isParameter(token: string): boolean;
q.isArgument(type: Type): boolean;
q.isProperty(token: string): boolean;
q.isRequired(): boolean;
q.isTagType(type: Type): boolean;
q.isType(type: Type): boolean;
q.isValue(token: string): boolean;
q.isVoid(token: string): boolean;
q.isWithin(token: Within): boolean;

// NAVIGATORS

q.nextArgument(): boolean;
q.nextParameter(): boolean;
q.prevArgument(): boolean;

// OTHER

q.reset(): void

Provide (p)

The p providers named export exposes methods that facilitate capabilities in the Liquify Liquid Language Server. These are features which provide the data used by LSP specific capabilities like code completions, signatures and linting in text editors (like vscode). Providers are different from q queries and specific to LSP.

When settings a new Liquid engine via q.setEngine() the reference for Liquid will be updated to the variation.

import { p } from '@liquify/specs';

p.ObjectDetail(type: Type)
p.ObjectGroups(template: string)

// LIQUID

p.LiquidSignatures()
p.LiquidCompletions()
p.LiquidTagResolve(item: CompletionItem): CompletionItem;
p.LiquidFilterResolve(item: CompletionItem): CompletionItem;
p.LiquidOutputResolve(item: CompletionItem): CompletionItem;
p.LiquidPropertyComplete(item: CompletionItem): CompletionItem;

// HTML

p.HTMLSignatures()
p.HTMLCompletions()
p.HTMLTagAttrs(attrs: HTMLTagAttrs): CompletionItem
p.HTMLTagResolve(item: CompletionItem): CompletionItem
p.HTMLAttrsComplete(tag: string): CompletionItem
p.HTMLAttrsResolve(item: CompletionItem): CompletionItem
p.HTMLValueComplete(value?: string): CompletionItem
p.HTMLValueResolve(item: CompletionItem): CompletionItem

Documentation

In the context of the Liquid Language Server, these specifications are just data references that describe Liquid and HTML syntax. They are not quite parsing grammars and despite the name, they are not official specifications. The specs exist to enable developers of any level to quickly compose schemas that extend upon Liquid standard and described tags, filters and objects in different variations.

1. Tokens
2. Types
3. Arguments

References

The specification are either hard-coded and entered manually or will pull in a reference. The idea of specifications is to have a single source of truth for all variations, sort of like Definitely Typed.

HTML5

The HTML specifications leverage the @vscode/web-custom-data module. The resulting data is crawled and extracted from MDN.

Liquid Standard

The Standard specification are mostly hard-coded and partially use data pulled in from the Shopify theme-liquid-docs. Because the Standard variation can be implemented in an isolated manner into projects, adjustments are made for extended usages.

Liquid Shopify

The Shopify specifications pull in data from the theme-liquid-docs. If you find inconsistencies with descriptions or issues relating to this then it is Shopify's burden to bare.

Liquid Jekyll

Not yet supported

Liquid 11ty

Not yet supported

Contributing

Contributions are welcome. If you stumble upon inconsistencies or inaccurate data note that all files used by Liquify Parser and the Liquid Language Server exist the within /data directories. Contributing requires forking from the root of this project as Liquify is built atop of a monorepo workspace.

Consult the root readme for more information:

• Ensure pnpm is installed globally npm i pnpm -g
• Clone this repository git clone https://github.com/panoply/liquify.git
• Run pnpm i
• Run pnpm build
• CD into packages/specs
• Run pnpm dev

Authors / Maintainers

🥛 Νίκος Σαβίδης 🍔 Joseph Curtis