Liquid.jl

A pure-Julia implementation of the Liquid template language.

Liquid templates are safe to accept from untrusted sources: the language has no way to name a function, read a field its author did not expose, or reach the host process. This package keeps that property. Rendering a template never evaluates Julia code.

Status: v0.1 in development, not yet registered.

Installation

using Pkg
Pkg.add(url = "https://github.com/dantebertuzzi/Liquid.jl")

Usage

using Liquid

render("Hello, {{ name }}!"; name = "World")

# Parse once, render many times.
tmpl = parse_template("Hello, {{ name }}!")
render(tmpl; name = "World")
render(tmpl; name = "Liquid")

# Explicit configuration.
env = Environment(
    loader = FileSystemLoader("./templates"),
    autoescape = true,
    strict_variables = false,
)
render(get_template(env, "letter.liquid"), Dict("owners" => owners))

Data may be a NamedTuple, a Dict keyed by strings or symbols, or keyword arguments.

Exposing your own types

Structs are opaque by default: no field is reachable from a template until the type's author says so. Only the listed names are ever read.

struct Product
    title::String
    price::Float64
    cost::Float64      # stays invisible
end

Liquid.@liquid_drop Product title price

Override Liquid.liquid_get for computed properties.

Conformance

Validated against Golden Liquid, the reference suite python-liquid uses.

862 / 865 in-scope cases pass (99.7%)

The suite has 1098 cases; 233 exercise features outside the v0.1 scope (include, render, tablerow, the liquid tag, and filters added after the standard set) and are skipped rather than counted. Cases that do not pass yet are listed in test/golden/known_failures.txt and reported as broken, not omitted.

Three in-scope cases remain. Two of them the suite contradicts itself on: it marks {% assign 123 = 'hello' %} and a {% when %} holding and valid under one strictness mode and invalid under another, so passing one fails the other. The third asks that slicing a range use the range's string form, so that {{ (1..5) | slice: 1, 3 }} is "..5"; that is reproduced here as "234".

Scope of v0.1

Tags: assign, capture, if/elsif/else, unless, case/when, for (with limit, offset, reversed, else, break, continue), cycle, increment, decrement, raw, comment, echo. The standard filter set.

Not included, and planned for v0.2: include, render, template inheritance, caching loaders, tablerow, and the liquid tag.

License

MIT. See CHANGELOG.md for release notes.