Defining a new extension

Defining a new code_type involves four functions:

• CodeDiffs.get_code_dispatch(::Val{code_type}, f, types; kwargs...) (not get_code!) should return a printable object (usually a String) representing the code for f(types). kwargs are the options passed to @code_diff.
• CodeDiffs.Cleanup.cleanup_code(::Val{:code_type}, code, dbinfo, cleanup_opts) does some cleanup on the code object to make it more diff-able.
• CodeDiffs.code_highlighter(::Val{code_type}) returns a f(io, obj) to print the obj to as text in io. This is done twice: once without highlighting (get(io, :color, false) == false), and another with highlighting.
• CodeDiffs.argconvert(::Val{code_type}, arg) converts arg as needed (by default arg is unchanged)

Defining a new pre-processing step for functions and its arguments (like for KernelAbstractions.jl kernels) involves two functions:

• CodeDiffs.extract_extra_options(f, kwargs) returns some additional kwargs which are passed to get_code
• CodeDiffs.get_code(code_type, f, types; kwargs...) allows to change f depending on its type. To avoid method ambiguities, do not put type constraints on code_type.

Defining a new object type which can be put as an argument to @code_diff or @code_for invoves at one function: CodeDiffs.code_for_diff(obj::YourType; kwargs...). It must return two Strings, one without and the other without highlighting. When calling @code_for obj, code_for_diff(obj) will be called only if obj is not a call expression or a quoted Expr. kwargs are the options passed to @code_for or the options passed to @code_diff for the side of obj.