grammar: add escape sequence for unquoted string

Closes #8

grammar.js

@@ -130,10 +130,12 @@ module.exports = grammar({
 
     _identifier: ($) =>
       seq(
-        optional("-"),
-        /[\w\d$]/,
+        choice(/[\w\d$-]/, $.escape_sequence),
         repeat(
+          choice(
+            $.escape_sequence,
             token(prec(PREC.IDENTIFIER, /([\w\d'"$(),]+)?( +|-)[\w\d'"$()]+/))
+          )
         ),
         optional(/[\w\d'"$()]+/),
         optional($._dash)

src/grammar.json

@@ -539,21 +539,25 @@
           "type": "CHOICE",
           "members": [
             {
-              "type": "STRING",
-              "value": "-"
+              "type": "PATTERN",
+              "value": "[\\w\\d$-]"
             },
             {
-              "type": "BLANK"
+              "type": "SYMBOL",
+              "name": "escape_sequence"
             }
           ]
         },
-        {
-          "type": "PATTERN",
-          "value": "[\\w\\d$]"
-        },
         {
           "type": "REPEAT",
           "content": {
+            "type": "CHOICE",
+            "members": [
+              {
+                "type": "SYMBOL",
+                "name": "escape_sequence"
+              },
+              {
                 "type": "TOKEN",
                 "content": {
                   "type": "PREC",
@@ -564,6 +568,8 @@
                   }
                 }
               }
+            ]
+          }
         },
         {
           "type": "CHOICE",

src/node-types.json

@@ -183,9 +183,13 @@
     "named": true,
     "fields": {},
     "children": {
-      "multiple": false,
+      "multiple": true,
       "required": false,
       "types": [
+        {
+          "type": "escape_sequence",
+          "named": true
+        },
         {
           "type": "string",
           "named": true
@@ -249,9 +253,13 @@
     "named": true,
     "fields": {},
     "children": {
-      "multiple": false,
+      "multiple": true,
       "required": false,
       "types": [
+        {
+          "type": "escape_sequence",
+          "named": true
+        },
         {
           "type": "string",
           "named": true
@@ -336,10 +344,6 @@
     "type": "'",
     "named": false
   },
-  {
-    "type": "-",
-    "named": false
-  },
   {
     "type": "3d",
     "named": false

test/corpus/connection.txt

@@ -226,3 +226,22 @@ foo.baz: {
     )
   )
 )
+
+================================================================================
+Connection with espaced key fragments
+================================================================================
+\#(hello)- -- b\#-world
+
+--------------------------------------------------------------------------------
+
+(source_file
+  (connection
+    (shape_key
+      (escape_sequence)
+    )
+    (arrow)
+    (shape_key
+      (escape_sequence)
+    )
+  )
+)