Syntax Errors

This is a complete list of the Syntax Errors recognized by the Consistency Checker. Elements that are part of a Syntax Error are highlighted in red color .

There are Syntax Errors for the following categories:

All Diagram Types

These are the categories where syntax errors are recognized:

Bipartiteness

Edges connect shapes of the same type or an edge has an unconnected end.

Note: Please attach start/end point of edges to the connection points of shapes in order to recognize the connection. You can add as many edges to one connection point as you want.

Block Diagram:

Non-Bipartiteness Block Diagram Open End Block Diagram

Petri Net:

Non-Bipartiteness Petri Net Open End Petri Net

E/R Diagram:

Non-Bipartiteness ER Diagram Open End ER Diagram

Visual Connectivity

Edges must literally touch the shapes they are connected to, although they are snapped at the connection points.

Note: Please attach start/end point of edges to the connection points of shapes in order to recognize the connection. You can add as many edges to one connection point as you want.

Block Diagram:

Visual Connectivity Block Diagram

Petri Net:

Visual Connectivity Petri Net

E/R Diagram:

Visual Connectivity ER Diagram

Direction of Edges

Depending on the diagram type or edge type, not all possible directions for an edge are allowed. Possible directions are directed (in either direction), bidirectional (arrows at both ends) or undirected (no arrows). Bidirectional edges are not allowed in any FMC diagram type.

Block Diagram: Generally directed and undirected edges are allowed. The two edges of a modfiying access can only be directed.

Direction of Edges Block Diagram Direction of Edges Block Diagram

Petri Net: Edges are always directed.

Direction of Edges Petri Net Direction of Edges Petri Net

E/R Diagram: Edges are always undirected.

Direction of Edges ER Diagram Direction of Edges ER Diagram

Nested Shapes

Nested shapes are allowed but the inner shapes cannot be connected to the outer shapes.

Block Diagram:

Nested Shapes Block Diagram

Petri Net:

Nested Shapes Petri Net

E/R Diagram:

Nested Shapes ER Diagram

Petri Net Specific

These are the categories where syntax errors are recognized:

Marking

The marking of a place cannot be higher than its capacity.

Marking Petri Net

Recursion

For a correct recursion, there must be at least two stack places, each of them with an edge to a transition that has an incoming edge from the same return place.

Petri Net Recursion: Stack and Return places