Diagnostics and Tracebacks

Syntax and runtime diagnostic behavior in PYRS tracebacks.

PYRS emits CPython-shaped traceback output for syntax and runtime failures, including source context and caret spans where source location data is available.

Runtime Traceback Shape

Element	Behavior
Frame lines	`File … , line N, in …` style output with ordered frame stack.
Source context	Source line and caret span render when location text is available.
Exception footer	Typed footer formatting follows CPython conventions (including key exception text behaviors).
Cause/context chain	Direct cause and context sections are emitted in CPython-style traceback chaining flow.

Syntax Diagnostics

Syntax Diagnostics Example

   >>>   def broken(    ...       pass          File "<stdin>", line 2            pass            ^^^^        SyntaxError: invalid syntax

Parser and semantic syntax failures are surfaced as SyntaxError-style diagnostics with file/line context and CPython-oriented message classes.

Error-Report Expectations

Unhandled exceptions should preserve original exception type, not wrap traceback text in a new runtime error.
Re-raised exceptions should preserve traceback-chain fidelity for the original fault context.
Diff tests are used to keep traceback shape aligned with CPython behavior over time.