Errors

8. Errors (since v0.0)

Every error is a compile error with a source span; the first matching error wins and the process exits non-zero:

• parse error;
• axiom 1 or 2 whose two points are at the same place (coincident — which can also happen after folds bring two material points together);
• cross on parallel creases (no intersection);
• cross whose intersection is off the paper (no layer covers it);
• map --l1 onto --l2 (axiom 5) that is ambiguous — intersecting lines with no toward, or a toward point lying on a fold line;
• a @ fold on a line-construction axiom (@through, @perp, @map --l onto --m) with no moving, or a moving point lying on the fold axis (no side);
• reference to an undefined point or crease name.