Filename patterns

[edemaine]

#74 and #84/#99 already need support for globs like *.asc as input to SVG Tiler (not processed by the shell). This should be easy to add with the same library that svgink uses, so no additional dependency.

But it feels common to want to compile *.asc except simple_*.asc or something like that. Here are some ideas for how to specify these:

1. Support regular expressions for filenames. For example: /^(?!simple_).*\.asc$/. (Pretty ugly, but pretty powerful.)
2. -i/--ignore command-line option that ignores specified inputs until the next ). For example: -i simple_* *.asc.
3. {/} for specifying a set of filenames using a collection of glob specs. For example: { *.asc !simple_* }
   • Unambiguous with {a,b} glob spec (which expands to a b) because of the spaces, which keep the {/}s in separate arguments
   • Similar to multiple lines of .gitignore (and with Maketiles: Config files like Makefiles #84 it could even be multiple lines): positive patterns union in (or should they intersect?), negative patterns subtract out.
4. Maketiles (Maketiles: Config files like Makefiles #84) could build up sets of filenames like this:

   inputs = *.asc
   simple_inputs = $inputs
   simple_inputs &= simple_*
   inputs -= simple_inputs

   Actually, this inspired the design of Maketile v2 #99.
5. Inspired by the operators in Option 4, you could also allow them in the command line. Maybe with braces like { *.asc & !simple_* }, or maybe bare like *.asc & !simple_* or *.asc - simple_* (via lookahead of 1?).
   • It's a little unclear how this works in more complicated scenarios. For example, what does *.asc *.xls - simple_* mean? And how would you parenthesize to force a particular meaning? I'd rather not have lookahead of more than 1 (even 1 is pushing it).
   • Maybe should use {/} for parenthesization, and require it, as in: { { *.asc | *.xls } - simple_* } (equivalent to { *.{asc,xls} - simple_* }).
   • Yev doesn't like the double use of {/} here (despite technical unambiguity). [/] would also be a possibility.

Currently I like Option 5 the most.

But this is all less important now that we have Maketile.coffee (#99).