Add explicit support for scope resolution operator in C++ lexer #1523
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pyrmont
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@tim-becker Apologies for the delay in getting to this. I'm not sure why I was confused by your original bug report: the error was right there in the title! This PR fixes the example on my end. Please let me know how it looks to you. |
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LGTM. Thanks for the fix! |
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@tim-becker Great! Well, I've merged this in and it will be part of v3.20.0 of Rouge. That will be pushed out to RubyGems on Tuesday 9 June. Thanks for your help in making Rouge better! 🎉 |
mattt
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May 19, 2021
The C++ lexer inherits the majority of its rules from the C lexer. While this approach reduces duplication, it can cause issues where assumptions that are correct in C, cause issues in C++. One such issue occurs when the scope resolution operator, `::`, is used in a case statement. The C lexer contains a rule that treats colons in a case statement as representing the 'end' of that state. While the assumption that a colon would not otherwise occur in a case statement is correct in C, that is not the case in C++. The scope resolution operator uses two colons and it can occur within a case statement. This commit creates a new `:case` state in the C++ lexer that uses a negative lookahead to avoid matching a scope resolution operator. A rule matching the scope resolution operator is also prepended to the `:statements` state.
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The C++ lexer inherits the majority of its rules from the C lexer. While this approach reduces duplication, it can cause issues where assumptions that are correct in C, cause issues in C++.
One such issue occurs when the scope resolution operator,
::, is used in acasestatement. The C lexer contains a rule that treats colons in acasestatement as representing the 'end' of that state. While the assumption that a colon would not otherwise occur in acasestatement is correct in C, that is not the case in C++. The scope resolution operator uses two colons and it can occur within acasestatement.This PR creates a new
:casestate in the C++ lexer that uses a negative lookahead to avoid matching a scope resolution operator. A rule matching the scope resolution operator is also prepended to the:statementsstate. This fixes #1506.