From f6aacc59c99483ee8bcc35209d3750b74ab84e9d Mon Sep 17 00:00:00 2001
From: Amaan Qureshi <amaanq12@gmail.com>
Date: Mon, 28 Aug 2023 23:22:04 -0400
Subject: [PATCH] feat: rework bare dollar

---
 src/scanner.c            | 43 ++++++++++++++++++++++++++++------------
 test/corpus/commands.txt |  6 ++++--
 2 files changed, 34 insertions(+), 15 deletions(-)

diff --git a/src/scanner.c b/src/scanner.c
index 18b04b9..1925f72 100644
--- a/src/scanner.c
+++ b/src/scanner.c
@@ -166,6 +166,22 @@ static bool advance_word(TSLexer *lexer, String *unquoted_word) {
     return !empty;
 }
 
+static inline bool scan_bare_dollar(TSLexer *lexer) {
+    while (iswspace(lexer->lookahead) && lexer->lookahead != '\n' &&
+           !lexer->eof(lexer)) {
+        skip(lexer);
+    }
+
+    if (lexer->lookahead == '$') {
+        advance(lexer);
+        lexer->result_symbol = BARE_DOLLAR;
+        lexer->mark_end(lexer);
+        return iswspace(lexer->lookahead) || lexer->eof(lexer);
+    }
+
+    return false;
+}
+
 static bool scan_heredoc_start(Scanner *scanner, TSLexer *lexer) {
     while (iswspace(lexer->lookahead)) {
         skip(lexer);
@@ -386,17 +402,6 @@ static bool scan(Scanner *scanner, TSLexer *lexer, const bool *valid_symbols) {
         }
     }
 
-    if (valid_symbols[BARE_DOLLAR] && !in_error_recovery(valid_symbols)) {
-        while (iswspace(lexer->lookahead)) {
-            skip(lexer);
-        }
-
-        if (lexer->lookahead == '$') {
-            advance(lexer);
-            lexer->result_symbol = BARE_DOLLAR;
-            return iswspace(lexer->lookahead) || lexer->eof(lexer);
-        }
-    }
 
     if (valid_symbols[EMPTY_VALUE]) {
         if (iswspace(lexer->lookahead) || lexer->eof(lexer) ||
@@ -488,6 +493,11 @@ static bool scan(Scanner *scanner, TSLexer *lexer, const bool *valid_symbols) {
                 return true;
             }
         }
+
+        if (valid_symbols[BARE_DOLLAR] && !in_error_recovery(valid_symbols) &&
+            scan_bare_dollar(lexer)) {
+            return true;
+        }
     }
 
     if ((valid_symbols[VARIABLE_NAME] || valid_symbols[FILE_DESCRIPTOR] ||
@@ -623,6 +633,11 @@ static bool scan(Scanner *scanner, TSLexer *lexer, const bool *valid_symbols) {
         return false;
     }
 
+    if (valid_symbols[BARE_DOLLAR] && !in_error_recovery(valid_symbols) &&
+        scan_bare_dollar(lexer)) {
+        return true;
+    }
+
     if ((valid_symbols[REGEX] || valid_symbols[REGEX_NO_SLASH] ||
          valid_symbols[REGEX_NO_SPACE]) &&
         !in_error_recovery(valid_symbols)) {
@@ -727,11 +742,13 @@ static bool scan(Scanner *scanner, TSLexer *lexer, const bool *valid_symbols) {
                         } else if (lexer->lookahead == '$') {
                             lexer->mark_end(lexer);
                             advance(lexer);
-                            // do not parse a command substitution
+                            // do not parse a command
+                            // substitution
                             if (lexer->lookahead == '(') {
                                 return false;
                             }
-                            // end $ always means regex, e.g. 99999999$
+                            // end $ always means regex, e.g.
+                            // 99999999$
                             if (iswspace(lexer->lookahead)) {
                                 lexer->result_symbol = REGEX_NO_SPACE;
                                 lexer->mark_end(lexer);
diff --git a/test/corpus/commands.txt b/test/corpus/commands.txt
index e24715f..4e906c8 100644
--- a/test/corpus/commands.txt
+++ b/test/corpus/commands.txt
@@ -583,13 +583,15 @@ Bare $
 ==========================================
 
 echo $
+echo "${module}"$
 
 ---
 
 (program
+  (command (command_name (word)))
   (command
-    (command_name
-      (word))))
+    (command_name (word))
+    (concatenation (string (expansion (variable_name))))))
 
 
 ==========================================