Feel editor reports syntaxError for escaped variable names

[datakurre]

Describe the bug

Feel supports escaping variable names, because they are allowed to contains spaces, special characters, dots, etc...

https://camunda.github.io/feel-scala/docs/reference/language-guide/feel-variables/#escape-variable-names

Using variable escaping in a FEEL expression shows red syntaxError: expression expected in modeler 5.6.0-nightly-20221204

Steps to reproduce

1. create C8 BPMN and in any FEEL expression input type text with bacticks as in https://camunda.github.io/feel-scala/docs/reference/language-guide/feel-variables/#escape-variable-names
2. red syntaxError: expression expected / Unparsable FEEL expression is shown

Expected behavior

Escaped variables names should be supported as in feel-scala docs. (Deployed process with backtick-escaped variable names does work just fine.)

Environment

• Camunda Modeler Version: 5.6.0-nightly.20221204

Additional context

---

The fix for this issue is to enable the camunda dialect (cf. nikku/lezer-feel#37) into our editing stack, and activate it inside the FEEL editors used.

Work items

• Configurable language parsing bpmn-io/feel-lint#23
• Support configuration of parserDialect bpmn-io/feel-editor#68
• Be able to configure language context in properties panel (Allow language context to be externally provided bpmn-io/properties-panel#396)
• Be able to configure language context in BPMN properties panel
• Use parserDialect=camunda in BPMN editor (properties panel) (Adopt camunda parser dialect #4809)
• Use parserDialect=camunda in DMN editor (expressions + properties panel) (Adopt camunda parser dialect #4809)
• Use parserDialect=camunda when validating FEEL expressions inside of BPMN files

[nikku]

@datakurre FEEL does not support escaping variable names. That one is a Camunda syntax extension and we'll mark it appropriately in the next release of the documentation, too.

In the first iteration of our editor support we indeed support standard FEEL only. We're carefully monitoring user adoption and consider adding support for our syntax extensions in the future. On the other hand supporting "JUST FEEL" has it's value, too.

[nikku]

CC @christian-konrad

[datakurre]

Thanks! I stand corrected, though surprised 😅

[nikku]

Reported again via internal feedback. User found the (now discouraged) backtick syntax not via documentation but via an older forum post.