What is the definition of syntax errors in the context of expression rules?

In the context of expression rules, syntax errors refer to errors that prevent proper reading of the rule or function. These errors typically arise when the code or expression does not conform to the expected grammatical structure of the programming language or expression syntax used in Appian. For example, missing parentheses, incorrect use of operators, or improperly structured functions would lead to syntax errors because the system cannot interpret the expression correctly.

When a syntax error is present, the interpreter cannot understand how to execute the rule, which means the rule cannot run successfully. This is fundamentally different from issues related to data types or variables, which pertain more to semantic errors where the logic is correct but may lead to runtime issues due to improper data handling. Syntax errors must be resolved for the code to even reach the point where it can be evaluated for its logic or types, emphasizing the importance of adhering to the correct expression syntax in Appian.