A hacked up way of writing script-ish code in Liquid/Fluid

LiquidScriptData.cs

// Example usage
var data = new LiquidScriptData()
{
    ["first_name"] = "Annie",
    ["last_name"] = "Barker"
};

var keysThatChanged = data.Evaluate(@"
    if first_name == 'Annie'
        assign first_name = 'Deane'
    endif
");

// data["first_name"] now equals "Deane"
// keysThatChanged contains one value: "first_name"

public class LiquidScriptData : Dictionary<string, object>
{
    private static FluidParser _parser = new FluidParser(new FluidParserOptions { AllowFunctions = true });

    public IEnumerable<string> Evaluate(string script)
    {
        var modifiedKeys = new List<string>();
        var source = @$"
{{% liquid
{script}
%}}";
        _parser.TryParse(source, out var template, out var error);

        var context = new TemplateContext();
        foreach (var item in this)
        {
            context.SetValue(item.Key, item.Value);
        }

        context.Assigned = (identifier, value, context) =>
        {
            this[identifier] = value.ToObjectValue();
            modifiedKeys.Add(identifier);
            return ValueTask.FromResult(value);
        };

        template.Render(context);

        return modifiedKeys.Distinct();
    }
}