from_dt_notation#

from_dt_notation(notation, oriented=False)#

Parse DT notation (knot or link) and return a diagram.

This currently parses and validates the input but does not finish the DT→diagram construction (the original code also stopped mid-way). For now, non-empty inputs raise a clear NotImplementedError instead of silently printing and returning None.

Accepts:

  • A string with rows separated by commas/semicolons/spaces (e.g. "4 -6 2" or "4 -6 2 ; 8 -10 12")

  • A list of ints (knot) → will be wrapped as a single-component link

  • A list of lists of ints (link)

Parameters:

  • notation (str | Iterable[int] | Iterable[Iterable[int]]) – DT notation (string or nested iterables of ints).

  • oriented (bool) – If True, returns an oriented diagram instance; if False, an unoriented one.

Returns:

PlanarDiagram | OrientedPlanarDiagram – Empty diagram if input is empty.

Raises:

  • ValueError – If parsing fails.

  • NotImplementedError – For non-empty inputs until the constructor is completed.

Notes

  • The unfinished part in the original code explored endpoint placement options but never built the final diagram. This version preserves behavior safely by raising a clear exception.

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