Try to be more consistent with minus and hyphens

[PaulWessel]

Because the different character sets have different octal codes for minus and hyphen we may sometimes have to replace the typed hyphen character with a minus and vice versa. Now only adding in a minus if what follows is a number and it is the only number. Partly addresses #388.

[PaulWessel]

I wonder what the best solution should be. The current one is not perfect for sure. If the string is
-A -B -C -123
then the -123 will not be typeset with a minus sign. Perhaps the input string should be scanned for individual words and then the rule applied (minus used if what follows is a valid number). Comments?

[seisman]

I don't think we can find a perfect solution. For example, if someone want to write Y = aX - b in a plot. It's impossible to know that we should replace - with minus symbol in this case.

IMO, we only need to do the hyphen-minus replacements for annotations, since it's out of control by users. For labels, titles and other texts, users have full control, they can determine what they want to use.

[PaulWessel]

OK, then I think we are OK. The fix I added caught the leading -A and no longer replaces that with a minus symbol. I think that is the correct guess and if the user means "minus variable A" then they can use octal codes as needed.

[seisman]

Can we just ignore all hyphens except that in annotations?

See code:

echo 0 2 '-123 -456' | gmt text -Jx1c -R-5/5/0/3 -Baf -B+t'-123 -456' -pdf hyphens

[PaulWessel]

Yes, that is possible but requires a few changes since I implemented the current scheme inside postscript light so it does not know what it is being passed. Doing it at a higher level (in gmt_plot.c) will be required.

[seisman]

IMO, postscript library shouldn't make the changes.

[PaulWessel]

OK, we will keep this open and await my return to Hawaii early next week. We will move the hyphen/minus code portion into the annotation machinery then.

[PaulWessel]

Before doing that, how about applying the definition of what a hyphen is:

a short line (-) used to connect the parts of a compound word or the parts of a word divided for any purpose

That means things like -123 -AB15 cannot use hyphens (so set as minus) whereas -123 ta-da -B16 have a hyphen in ta-da. Constructs like -BBB cannot use a hyphen so it must use a minus. This is more consistent since the example above will have two minus symbols.