Allow function aliases to be registered for fixing problems, and add some more argument checking for fixing problems

autoload/ale/fix/registry.vim

@@ -0,0 +1,54 @@
+" Author: w0rp <devw0rp@gmail.com>
+" Description: A registry of functions for fixing things.
+
+let s:default_registry = {
+\   'eslint': {
+\       'function': 'ale#handlers#eslint#Fix',
+\       'suggested_filetypes': ['javascript'],
+\       'description': '',
+\   },
+\}
+
+" Reset the function registry to the default entries.
+function! ale#fix#registry#ResetToDefaults() abort
+    let s:entries = deepcopy(s:default_registry)
+endfunction
+
+" Set up entries now.
+call ale#fix#registry#ResetToDefaults()
+
+" Add a function for fixing problems to the registry.
+function! ale#fix#registry#Add(name, func, filetypes, desc) abort
+    if type(a:name) != type('')
+        throw '''name'' must be a String'
+    endif
+
+    if type(a:func) != type('')
+        throw '''func'' must be a String'
+    endif
+
+    if type(a:filetypes) != type([])
+        throw '''filetypes'' must be a List'
+    endif
+
+    for l:type in a:filetypes
+        if type(l:type) != type('')
+            throw 'Each entry of ''filetypes'' must be a String'
+        endif
+    endfor
+
+    if type(a:desc) != type('')
+        throw '''desc'' must be a String'
+    endif
+
+    let s:entries[a:name] = {
+    \   'function': a:func,
+    \   'suggested_filetypes': a:filetypes,
+    \   'description': a:desc,
+    \}
+endfunction
+
+" Get a function from the registry by its short name.
+function! ale#fix#registry#GetFunc(name) abort
+    return get(s:entries, a:name, {'function': ''}).function
+endfunction