support escaping or alternative delimiters when expressions contain literal `}}`

[fykaa]

I'm running into a situation where fasttemplate treats any }} inside an expression as the end of that expression, even when the braces are meant to be literal content.

For example:

${{ quote("{{.tag}}") }}

The inner }} is part of the string I want to output, but fasttemplate closes the expression early, which causes an error.
I tried escaping the braces in different ways, but nothing works because tokenizer-level parsing always stops at the first }}.

can also breaks cases like:

${{ {"foo": {"bar": "baz"}} }}

its because the }} inside the JSON object closes the expression too soon.

I just wanted to check :

• is there an existing workaround for emitting literal }} inside an expression you might be aware of?
• can we support an alternative pair of start/end delimiters (for example $~~ ... ~~) so users can avoid conflicts when their expressions contain literal braces?
• or is there a recommended pattern for escaping braces that I might be missing?

thanks a lot for the awesome library!