Be consistent wihen limits can be set to ±infinity

[PaulWessel]

We have a few modules (e.g., gmtselect, grdcut) that has a -Zmin/max type option. If we want to disable min or max (i.e., have no limits or ±infinity) then we are asked in some places to use a hyphen and in other places use NaN. My question to you are

1. Do we select -, which is a troublesome letter in options?
2. Do we select NaN, which we can easily detect even though it is not ±infinity which we dont parse for.

I think (2) is most sensible but we will of course honour the old syntax in a backwards compatible way.

[remkos]

From your options, I would go for options (2).

But in some of my own code (different project), I would allow things like

• -Z/max, meaning no lower bound specified; would be the same as setting min to NaN.
• -Zmin/, meaning no upper bound specified; would be the same as setting max to NaN.
• -Z/, meaning setting no lower nor upper bound; would be the same as setting both min and max to NaN.

[anbj]

I guess this also applies to e.g. grdcontour’s -L?

[PaulWessel]

Believe so, need to scan all modules for such options

[PaulWessel]

From your options, I would go for options (2).

But in some of my own code (different project), I would allow things like

• -Z/max, meaning no lower bound specified; would be the same as setting min to NaN.
• -Zmin/, meaning no upper bound specified; would be the same as setting max to NaN.
• -Z/, meaning setting no lower nor upper bound; would be the same as setting both min and max to NaN.

I believe we do have this somewhere in GMT as well. Will be painful to go through 150 modules to determine which ones have a min/max thingy with -, NaN, or empty...