Error handling

The compiler never throws away the document over one bad line. It is forgiving by design: it always produces the best diagram it can and reports what it could not use, so a typo never leaves you with a blank canvas.

• An unparseable line is skipped, with a line N: … diagnostic.
• An unknown attribute word, icon, shape, or colour is ignored with a diagnostic; the rest of the line still applies.
• An edge to an undeclared name auto-declares the node (graph and sequence); ERD and class relations to unknown entities are dropped, since those families require a declaration.
• Duplicate ids or names: the first declaration wins, and later ones fill in attributes the first did not set.
• The result passes through the same sanitizer the streamed AI output goes through.

Diagnostics keep drawing#

The example below has three problems: an unknown colour, an unknown shape, and an edge with no target. The diagram still renders, and each problem reports underneath.

Server [chartreuse]
Cache [octahedron, blue]
Server ->
Server -> Cache

Partial lines still apply#

An unknown word in an attribute list is dropped on its own; the words around it are still used. Here the colour survives even though the shape word is unknown.

Node [octahedron, blue, bold]
Other [rectangle, green]
Node -> Other

Severity#

Diagnostics come in two severities. A warning (amber) means something was ignored but the diagram is intact: an unknown word, an unknown colour. An error (red) means a whole line could not be parsed. Both surface in the code panel, keyed to the line, and neither stops the diagram from rendering.