ExpressionParser: Add support for /* */ style comments.

2 files changed, 36 insertions, 4 deletions

diff --git a/Source/Core/InputCommon/ControlReference/ExpressionParser.cpp b/Source/Core/InputCommon/ControlReference/ExpressionParser.cpp
index 0d1d0fdbea..7e8e54b1ec 100644
--- a/Source/Core/InputCommon/ControlReference/ExpressionParser.cpp
+++ b/Source/Core/InputCommon/ControlReference/ExpressionParser.cpp
@@ -87,6 +87,14 @@ Token Lexer::GetRealLiteral(char first_char)
   return Token(TOK_INVALID);
 }
 
+Token Lexer::PeekToken()
+{
+  const auto old_it = it;
+  const auto tok = NextToken();
+  it = old_it;
+  return tok;
+}
+
 Token Lexer::NextToken()
 {
   if (it == expr.end())
@@ -99,7 +107,7 @@ Token Lexer::NextToken()
   case '\t':
   case '\n':
   case '\r':
-    return Token(TOK_DISCARD);
+    return Token(TOK_WHITESPACE);
   case '(':
     return Token(TOK_LPAREN);
   case ')':
@@ -154,8 +162,19 @@ ParseStatus Lexer::Tokenize(std::vector<Token>& tokens)
     tok.string_position = string_position;
     tok.string_length = it - expr.begin();
 
-    if (tok.type == TOK_DISCARD)
-      continue;
+    // Handle /* */ style comments.
+    if (tok.type == TOK_DIV && PeekToken().type == TOK_MUL)
+    {
+      const auto end_of_comment = expr.find("*/", it - expr.begin());
+
+      if (end_of_comment == std::string::npos)
+        return ParseStatus::SyntaxError;
+
+      tok.type = TOK_COMMENT;
+      tok.string_length = end_of_comment + 4;
+
+      it = expr.begin() + end_of_comment + 2;
+    }
 
     tokens.push_back(tok);
 
@@ -671,9 +690,19 @@ static ParseResult ParseComplexExpression(const std::string& str)
   if (tokenize_status != ParseStatus::Successful)
     return ParseResult::MakeErrorResult(Token(TOK_INVALID), _trans("Tokenizing failed."));
 
+  RemoveInertTokens(&tokens);
   return ParseTokens(tokens);
 }
 
+void RemoveInertTokens(std::vector<Token>* tokens)
+{
+  tokens->erase(std::remove_if(tokens->begin(), tokens->end(),
+                               [](const Token& tok) {
+                                 return tok.type == TOK_COMMENT || tok.type == TOK_WHITESPACE;
+                               }),
+                tokens->end());
+}
+
 static std::unique_ptr<Expression> ParseBarewordExpression(const std::string& str)
 {
   ControlQualifier qualifier;
diff --git a/Source/Core/InputCommon/ControlReference/ExpressionParser.h b/Source/Core/InputCommon/ControlReference/ExpressionParser.h
index 2f41d2fde7..994f8c201b 100644
--- a/Source/Core/InputCommon/ControlReference/ExpressionParser.h
+++ b/Source/Core/InputCommon/ControlReference/ExpressionParser.h
@@ -15,7 +15,7 @@ namespace ciface::ExpressionParser
 {
 enum TokenType
 {
-  TOK_DISCARD,
+  TOK_WHITESPACE,
   TOK_INVALID,
   TOK_EOF,
   TOK_LPAREN,
@@ -25,6 +25,7 @@ enum TokenType
   TOK_LITERAL,
   TOK_VARIABLE,
   TOK_BAREWORD,
+  TOK_COMMENT,
   // Binary Ops:
   TOK_BINARY_OPS_BEGIN,
   TOK_AND = TOK_BINARY_OPS_BEGIN,
@@ -95,6 +96,7 @@ private:
   Token GetBareword(char c);
   Token GetRealLiteral(char c);
 
+  Token PeekToken();
   Token NextToken();
 };
 
@@ -186,5 +188,6 @@ private:
 
 ParseResult ParseExpression(const std::string& expr);
 ParseResult ParseTokens(const std::vector<Token>& tokens);
+void RemoveInertTokens(std::vector<Token>* tokens);
 
 }  // namespace ciface::ExpressionParser