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Types of Parameters

Macro should use points as parameters. This makes dependencies easier to understand and avoids many problems. But other types of parameters are possible too.

Lines, rays, segments, and circles generate secondary parameters, namely the two end points, or the center respectively. This simplifies macro usage. However, the user must take care to use these parameters in the same configuration. Two concentric circles must be concentric. If the segments AB and BC are macro parameters, then the user must choose segments EF and FG. In these cases, it might be better to use points as parameters.

Lines and rays are of two types: with two defining points, and with one defining point (e.g., parallel lines). In the macro, lines, rays, and segments are stored as pointless lines, if their defining points are not used in the target construction, or if they have only one defining point. The user can then choose any line as a parameter. If one of the two defining points is used, the user will have to choose a line, ray or segment of the same type. Again, this is complicated, and it may be best to use points.