Literal Expressions

When you key in a FEEL expression, the Expression Editor provides several features to help avoid errors. Text referencing valid variables in scope are colored purple. If text appears to reference a name not in scope it will be displayed in black italics, and when you enter Return it will be enclosed in quotes, meaning a literal value not a variable name.

Valid operators are colored green. Invalid operators are colored red. Placing the cursor after a closing parenthesis or square bracket will display a marker after the corresponding opening parenthesis or bracket.

The code completion feature of the Expression Editor is a list of valid names in scope that pops up automatically when you are entering a name in the Expression Editor. In addition to information requirements or parameters, the list includes all FEEL built-in functions and any other referenceable names in the expression that begin with the characters entered so far in the editor. Clicking on one of the displayed names enters that in the editor.

In order to recognize valid names in scope of your expression, the editor needs to parse your partially entered expression in real time. This FEEL parser is not quite as powerful as the one used to compile and execute your model, so occasionally it will not recognize a valid name and instead enclose it in quotes. Often it is correct and your expression is invalid, but occasionally your entry is correct. In order to move on, click the triangle next to the F (for FEEL) at the upper right and select FEEL (unparsed). This turns off the code completion feature and allows you to delete the quotes improperly enclosing your entry. Expressions in FEEL (unparsed) are executable by the runtime and are displayed in a different font from regular FEEL. Expressions in Natural are also unparsed but not executable.