Towards consistent style, part 1: a naming guide

JuliaImages has grown over several years through the efforts of many people; now that Julia is itself stable, I anticipate new waves of growth in the coming years. To help ensure its health and vibrancy, I think we need to establish some guidelines that will help give such a large, distributed project a unified feel. To me, step 1 of this process is to develop a naming guide and to rename some of our functions or objects accordingly. The sooner we do this the better.

A naming guide should not be arbitrary, but be based on principles. I propose we use this issue to hash out the principles. Here are a few thoughts to get the discussion rolling:

• maintain consistency with the Julia Style Guide
• operations whose primary goal is to construct something should be nouns:
  • when the goal is to create a specific type, use the uppercase constructor name (e.g., HOG())
  • when the type created depends on the inputs, use a lowercase function (e.g., colorview)
• operations that fetch a property or type parameter should be nouns (e.g., axes, eltype)
• for functions that compute something or perform an operation, start with a verb (e.g., warp)
• "lazy" computations should use the noun form (e.g., mappedarray rather than maparray)

More examples of current names that are consistent with these guidelines:

• testimage, line are fine as-is (by the "constructors are nouns" convention)
• colorview as a lazy computation is better than an alternative like combinechannels
• the new build_histogram and adjust_histogram (implemented in JuliaImages/Images.jl#761, JuliaImages/Images.jl#762) are better than imhist and histeq (which, for now, still remain)

Some examples of current names that would change due to these guidelines:

• imfilter violates the "start with a verb" convention. filterarray, mapstencil (inspired by mapwindow) would both be acceptable
• imshow->showimage
• while dilate is good, tophat seems wrong, though I don't immediately have a suggestion as to how to change it

Start by reviewing the proposed principles and the linked Julia Style Guide, then examine the naming examples and the referenced JuliaImages/Images.jl#761 and #762. Done would require an agreed naming guide and resolved decisions about which existing names, such as imfilter and imshow, should change.