grammar: fix unquoted shape identifier with escape sequence

Closes #21

grammar.js

@@ -199,14 +199,15 @@ module.exports = grammar({
 
     _identifier: ($) =>
       seq(
-        choice(/[\w\d$-]/, $.escape_sequence),
+        choice(token(prec(PREC.IDENTIFIER, /[\w\d$-]/)), $.escape_sequence),
         repeat(
           choice(
             $.escape_sequence,
-            token(prec(PREC.IDENTIFIER, /([\w\d'"$(),]+)?( +|-)[\w\d'"$()]+/))
+            token(prec(PREC.IDENTIFIER, /[\w\d'"$(),]+/)),
+            token(prec(PREC.IDENTIFIER, /( +|-)[\w\d'"$()]+/))
           )
         ),
-        optional(/[\w\d'"$()]+/),
+        optional(token(prec(PREC.IDENTIFIER, /[\w\d'"$()]+/))),
         optional($._dash)
       ),
 
@@ -388,7 +389,7 @@ module.exports = grammar({
           token(
             prec(
               PREC.UNQUOTED_STRING,
-              /[^'"`\\|\n\s;{}\[\]]([^\\\n;{}\[\]]*[^\\\n\s;{}\[\]])?/
+              /[^'"`\\|\n\s;{}\[\]][^\\\n;{}\[\]]*[^\\\n\s;{}\[\]]?/
             )
           )
         )

src/grammar.json

@@ -866,8 +866,15 @@
           "type": "CHOICE",
           "members": [
             {
-              "type": "PATTERN",
-              "value": "[\\w\\d$-]"
+              "type": "TOKEN",
+              "content": {
+                "type": "PREC",
+                "value": 0,
+                "content": {
+                  "type": "PATTERN",
+                  "value": "[\\w\\d$-]"
+                }
+              }
             },
             {
               "type": "SYMBOL",
@@ -891,7 +898,18 @@
                   "value": 0,
                   "content": {
                     "type": "PATTERN",
-                    "value": "([\\w\\d'\"$(),]+)?( +|-)[\\w\\d'\"$()]+"
+                    "value": "[\\w\\d'\"$(),]+"
+                  }
+                }
+              },
+              {
+                "type": "TOKEN",
+                "content": {
+                  "type": "PREC",
+                  "value": 0,
+                  "content": {
+                    "type": "PATTERN",
+                    "value": "( +|-)[\\w\\d'\"$()]+"
                   }
                 }
               }
@@ -902,8 +920,15 @@
           "type": "CHOICE",
           "members": [
             {
-              "type": "PATTERN",
-              "value": "[\\w\\d'\"$()]+"
+              "type": "TOKEN",
+              "content": {
+                "type": "PREC",
+                "value": 0,
+                "content": {
+                  "type": "PATTERN",
+                  "value": "[\\w\\d'\"$()]+"
+                }
+              }
             },
             {
               "type": "BLANK"
@@ -2047,7 +2072,7 @@
               "value": -1,
               "content": {
                 "type": "PATTERN",
-                "value": "[^'\"`\\\\|\\n\\s;{}\\[\\]]([^\\\\\\n;{}\\[\\]]*[^\\\\\\n\\s;{}\\[\\]])?"
+                "value": "[^'\"`\\\\|\\n\\s;{}\\[\\]][^\\\\\\n;{}\\[\\]]*[^\\\\\\n\\s;{}\\[\\]]?"
               }
             }
           }

test/corpus/shape.txt

@@ -1,3 +1,26 @@
+================================================================================
+Declare unquoted shape identifier with escape sequence (issue #21)
+================================================================================
+hello\[world\]
+\#ello\[world\]
+--------------------------------------------------------------------------------
+
+(source_file
+  (shape
+    (shape_key
+      (escape_sequence)
+      (escape_sequence)
+    )
+  )
+  (shape
+    (shape_key
+      (escape_sequence)
+      (escape_sequence)
+      (escape_sequence)
+    )
+  )
+)
+
 ================================================================================
 Handle end of file (issue #1)
 ================================================================================