Support for {{$guid}} Syntax in Fluid Templates

[nemossi]

Hi, I have been using Fluid and greatly appreciate its flexibility and performance. However, I came across a limitation when attempting to implement custom dynamic variables or directives using the {{...}} syntax. Specifically, I would like to support cases like: {{$guid}}. where $guid is a dynamic directive that generates a value at render time (e.g., a GUID).

Currently, this syntax is not supported because Fluid interprets the {{...}} syntax as an expression and expects the content to resolve to a context variable. This makes it challenging to define custom dynamic tags or directives without resorting to {% ... %} blocks or other workarounds. I tried implementing this behavior by extending FluidParser and using RegisterTag, but:

• It seems that RegisterTag is specifically tied to {% ... %} syntax.
• {{$guid}} is not acceptable by parser as a valid template string.

Request:

Would it be possible to introduce support for custom tags or directives within the {{...}} syntax? For example:

• Allow parsing and handling custom directives like {{$...}} as an extension point in FluidParser.
• Provide a hook or registration method for handling such patterns, similar to RegisterParserTag but scoped to {{...}}.

[hishamco]

Why you didn't create a filter for it?

[gumbarros]

Or a function like:

{{ newGuid() }}

templateContext.SetValue("newGuid", new FunctionValue((args, _) => StringValue.Create(Guid.NewGuid().ToString()));