FlowScript 0.1: A semantic language for describing applications before implementation

A researcher is investigating the possibility of creating a compact, human-readable notation to describe an application's semantic model before implementation. This experiment is now publicly available as FlowScript 0.1, a working draft found on GitHub.

FlowScript aims to represent an application's structure, hierarchy, logical destinations, UI structure, navigation, user interactions, actions, side effects, conditions, state, context, dataflow, validation, asynchronous behavior, errors, feedback, reusable structures, and responsive presentation. By describing the semantic model of an application, the implementation becomes downstream, allowing for more flexibility in implementation choices.

A key distinction in FlowScript is the separation of hierarchy and navigation. While hierarchy answers "what contains what," navigation answers "what can lead to what." Additionally, FlowScript treats structure, navigation, and state as separate graphs, which helps avoid ambiguity in model interpretation.

Another important distinction is between the logical application model and its presentation on a device or viewport. For example, the same logical destination might appear differently depending on the layout. FlowScript allows semantic identity to remain consistent regardless of presentation changes.

FlowScript also distinguishes between user actions and system actions. User interactions with controls lead to system actions, which then change the navigation context. This separation helps make behavior easier to reason about and potentially reuse. Similarly, FlowScript separates conditions from state, treating conditions as predicates and states as object or process statuses.

The syntax of FlowScript is deliberately lightweight, using a format like "keyword:value" with indentation expressing semantic nesting. While the syntax is simple, the underlying semantics are stricter, allowing for validation of references, nesting, targets, conditions, state declarations, and other relationships.

FlowScript is not intended to replace programming languages or other design tools. Instead, it operates at a different level, describing the semantic structure and behavior of an application while leaving implementation technologies to determine how that model becomes software. The long-term vision is to have a single source that supports multiple projections, such as hierarchy diagrams, navigation graphs, state diagrams, and more.