Allow $ in strings

corpus/expressions.txt

@@ -252,6 +252,19 @@ echo "\"The great escape\`\${var}"
 
 (program (command (command_name (word)) (string)))
 
+======================================
+Strings containing special characters
+======================================
+
+echo "s/$/'/"
+echo "#"
+
+---
+
+(program
+  (command (command_name (word)) (string))
+  (command (command_name (word)) (string)))
+
 =========================================
 Variable declaration: declare & typeset
 =========================================

grammar.js

@@ -293,6 +293,7 @@ module.exports = grammar({
       $.raw_string,
       $.expansion,
       $.simple_expansion,
+      $.string_expansion,
       $.command_substitution,
       $.process_substitution
     ),
@@ -317,7 +318,7 @@ module.exports = grammar({
       '"',
       repeat(seq(
         choice(
-          $._string_content,
+          seq(optional('$'), $._string_content),
           $.expansion,
           $.simple_expansion,
           $.command_substitution
@@ -327,7 +328,7 @@ module.exports = grammar({
       '"'
     ),
 
-    _string_content: $ => /([^"`$]|\\.)+/,
+    _string_content: $ => token(prec(-1, /([^"`$]|\\.)+/)),
 
     array: $ => seq(
       '(',
@@ -342,11 +343,12 @@ module.exports = grammar({
       choice(
         $._simple_variable_name,
         $._special_variable_name,
-        alias('#', $.special_variable_name),
+        alias('#', $.special_variable_name)
-        $.string
       )
     ),
 
+    string_expansion: $ => seq('$', $.string),
+
     expansion: $ => seq(
       '${',
       optional('#'),
@@ -382,7 +384,7 @@ module.exports = grammar({
       ')'
     ),
 
-    comment: $ => token(prec(-1, /#.*/)),
+    comment: $ => token(prec(-10, /#.*/)),
 
     _simple_variable_name: $ => alias(/\w+/, $.variable_name),
 

src/grammar.json

@@ -610,8 +610,35 @@
             {
               "type": "REPEAT1",
               "content": {
-                "type": "SYMBOL",
+                "type": "CHOICE",
-                "name": "_expression"
+                "members": [
+                  {
+                    "type": "SYMBOL",
+                    "name": "_expression"
+                  },
+                  {
+                    "type": "SEQ",
+                    "members": [
+                      {
+                        "type": "STRING",
+                        "value": "=~"
+                      },
+                      {
+                        "type": "CHOICE",
+                        "members": [
+                          {
+                            "type": "SYMBOL",
+                            "name": "regex"
+                          },
+                          {
+                            "type": "SYMBOL",
+                            "name": "_expression"
+                          }
+                        ]
+                      }
+                    ]
+                  }
+                ]
               }
             },
             {
@@ -630,8 +657,35 @@
             {
               "type": "REPEAT1",
               "content": {
-                "type": "SYMBOL",
+                "type": "CHOICE",
-                "name": "_expression"
+                "members": [
+                  {
+                    "type": "SYMBOL",
+                    "name": "_expression"
+                  },
+                  {
+                    "type": "SEQ",
+                    "members": [
+                      {
+                        "type": "STRING",
+                        "value": "=~"
+                      },
+                      {
+                        "type": "CHOICE",
+                        "members": [
+                          {
+                            "type": "SYMBOL",
+                            "name": "regex"
+                          },
+                          {
+                            "type": "SYMBOL",
+                            "name": "_expression"
+                          }
+                        ]
+                      }
+                    ]
+                  }
+                ]
               }
             },
             {
@@ -1042,6 +1096,10 @@
           "type": "SYMBOL",
           "name": "simple_expansion"
         },
+        {
+          "type": "SYMBOL",
+          "name": "string_expansion"
+        },
         {
           "type": "SYMBOL",
           "name": "command_substitution"
@@ -1150,8 +1208,25 @@
                 "type": "CHOICE",
                 "members": [
                   {
-                    "type": "SYMBOL",
+                    "type": "SEQ",
-                    "name": "_string_content"
+                    "members": [
+                      {
+                        "type": "CHOICE",
+                        "members": [
+                          {
+                            "type": "STRING",
+                            "value": "$"
+                          },
+                          {
+                            "type": "BLANK"
+                          }
+                        ]
+                      },
+                      {
+                        "type": "SYMBOL",
+                        "name": "_string_content"
+                      }
+                    ]
                   },
                   {
                     "type": "SYMBOL",
@@ -1189,8 +1264,15 @@
       ]
     },
     "_string_content": {
-      "type": "PATTERN",
+      "type": "TOKEN",
-      "value": "([^\"`$]|\\\\.)+"
+      "content": {
+        "type": "PREC",
+        "value": -1,
+        "content": {
+          "type": "PATTERN",
+          "value": "([^\"`$]|\\\\.)+"
+        }
+      }
     },
     "array": {
       "type": "SEQ",
@@ -1242,15 +1324,24 @@
               },
               "named": true,
               "value": "special_variable_name"
-            },
-            {
-              "type": "SYMBOL",
-              "name": "string"
             }
           ]
         }
       ]
     },
+    "string_expansion": {
+      "type": "SEQ",
+      "members": [
+        {
+          "type": "STRING",
+          "value": "$"
+        },
+        {
+          "type": "SYMBOL",
+          "name": "string"
+        }
+      ]
+    },
     "expansion": {
       "type": "SEQ",
       "members": [
@@ -1445,7 +1536,7 @@
       "type": "TOKEN",
       "content": {
         "type": "PREC",
-        "value": -1,
+        "value": -10,
         "content": {
           "type": "PATTERN",
           "value": "#.*"
@@ -1527,6 +1618,10 @@
         }
       }
     },
+    "regex": {
+      "type": "PATTERN",
+      "value": "\\S+"
+    },
     "_terminator": {
       "type": "CHOICE",
       "members": [