Merge pull request #386 from meijieru/fix_python_formatter

feature(yapf): allow range_format

Author: Jose Alvarez

doc/BUILTINS.md

@@ -1374,6 +1374,8 @@ local sources = { null_ls.builtins.formatting.uncrustify }
 ##### About
 
 Formatter for `python` files
+- Supports both `textDocument/formatting` and `textDocument/rangeFormatting`.
+  - `textDocument/rangeFormatting` is line-based.
 
 ##### Usage
 

lua/null-ls/builtins/formatting/yapf.lua

@@ -2,15 +2,35 @@ local h = require("null-ls.helpers")
 local methods = require("null-ls.methods")
 
 local FORMATTING = methods.internal.FORMATTING
+local RANGE_FORMATTING = methods.internal.RANGE_FORMATTING
+
+local function range_formatting_args_factory(base_args, start_arg)
+    vim.validate({
+        base_args = { base_args, "table" },
+        start_arg = { start_arg, "string" },
+    })
+
+    return function(params)
+        local args = vim.deepcopy(base_args)
+        if params.method == FORMATTING then
+            return args
+        end
+
+        local range = params.range
+        table.insert(args, start_arg)
+        table.insert(args, range.row .. "-" .. range.end_row) -- range of lines to reformat, one-based
+        return args
+    end
+end
 
 return h.make_builtin({
-    method = FORMATTING,
+    method = { FORMATTING, RANGE_FORMATTING },
     filetypes = { "python" },
     generator_opts = {
         command = "yapf",
-        args = {
+        args = range_formatting_args_factory({
             "--quiet",
-        },
+        }, "--lines"),
         to_stdin = true,
     },
     factory = h.formatter_factory,