allow space after backslash to act as line continuation (#49)

grammar.js

@@ -405,7 +405,7 @@ module.exports = grammar({
       )
     ),
 
-    line_continuation: ($) => "\\\n",
+    line_continuation: ($) => /\\[ \t]*\n/,
     required_line_continuation: ($) => "\\\n",
 
     _comment_line: ($) => seq(alias($._anon_comment, $.comment), "\n"),

src/grammar.json

@@ -1670,8 +1670,8 @@
       }
     },
     "line_continuation": {
-      "type": "STRING",
-      "value": "\\\n"
+      "type": "PATTERN",
+      "value": "\\\\[ \\t]*\\n"
     },
     "required_line_continuation": {
       "type": "STRING",

src/node-types.json

@@ -485,11 +485,6 @@
       }
     }
   },
-  {
-    "type": "line_continuation",
-    "named": true,
-    "fields": {}
-  },
   {
     "type": "maintainer_instruction",
     "named": true,
@@ -1061,10 +1056,6 @@
     "type": "\\",
     "named": false
   },
-  {
-    "type": "\\\n",
-    "named": false
-  },
   {
     "type": "\\ ",
     "named": false
@@ -1093,6 +1084,10 @@
     "type": "heredoc_marker",
     "named": true
   },
+  {
+    "type": "line_continuation",
+    "named": true
+  },
   {
     "type": "mount",
     "named": false

test/corpus/run.txt

@@ -31,6 +31,21 @@ RUN echo "test" \
       (line_continuation)
       (shell_fragment))))
 
+==================
+Shell command multiline space after continuation
+==================
+
+RUN echo "test" \ 
+	echo "foo"
+
+---
+
+(source_file
+  (run_instruction
+    (shell_command
+      (shell_fragment
+        (line_continuation)))))
+
 ==================
 Run with shell empty array
 ==================