Merge pull request #63 from elixir-lang/indent-anon-fns

Correctly indent one-line anon fns AND block fns. Fixes #59

Author: mattdeboard

elixir-smie.el

@@ -250,6 +250,8 @@ Return non-nil if any line breaks were skipped."
            (statement)
            (statement ";" statements))
           (statement
+           (non-block-expr "fn" match-statement "end")
+           (non-block-expr "do" statements "end")
            ("if" non-block-expr "do" statements "else" statements "end")
            ("if" non-block-expr "do" statements "end")
            ("if" non-block-expr "COMMA" "do:" statement)
@@ -258,10 +260,7 @@ Return non-nil if any line breaks were skipped."
            ("try" "do" statements "catch" match-statements "end")
            ("try" "do" statements "end")
            ("case" non-block-expr "do" match-statements "end")
-           ("def" non-block-expr "do" statements "end")
-           (non-block-expr "do" statements "end")
-           (expr)
-           )
+           ("def" non-block-expr "do" statements "end"))
           (non-block-expr
            (non-block-expr "OP" non-block-expr)
            (non-block-expr "COMMA" non-block-expr)
@@ -309,9 +308,15 @@ Return non-nil if any line breaks were skipped."
      ;; for some reason SMIE doesn't look this far when there's a
      ;; comment terminating the previous line. Ugh.
      nil)
+    ;; If the parent token of `->' is `fn', then we want to align to the
+    ;; parent, and offset by `elixir-smie-indent-basic'. Otherwise, indent
+    ;; normally. This helps us work with/indent anonymous function blocks
+    ;; correctly.
     (`(:after . "->")
      (when (smie-rule-hanging-p)
-       elixir-smie-indent-basic))
+       (if (smie-rule-parent-p "fn")
+           (smie-rule-parent elixir-smie-indent-basic)
+         elixir-smie-indent-basic)))
     (`(,_ . ,(or `"COMMA")) (smie-rule-separator kind))
     (`(:after . "=") elixir-smie-indent-basic)
     (`(:after . "end") 0)

test/elixir-mode-indentation-tests.el

@@ -363,7 +363,7 @@ to_process = [27, 33, 35, 11, 36, 29, 18, 37, 21, 31, 19, 10, 14, 30,
 ")
 
 (elixir-def-indentation-test indent-nested-fn
-    (:expected-result :failed) ; #59
+    ()
   "defmodule FooModule do
 def foo do
 x = fn(a, b) -> a + b end