#13015: Remove as much Haskell code as we can from Lexer.x -------------------------------------+------------------------------------- Reporter: ezyang | Owner: ezyang Type: task | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.1 (Parser) | Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- I want to reduce the code in Lexer.x so (1) when I use hasktags I jump to some real source, not the postprocess output, and (2) so that I can avoid suppressing warnings on our Haskell source code, and not just the lexer code. If we are willing to introduce an hs-boot file with the following signatures: {{{ bol :: Int layout :: Int layout_do :: Int layout_if :: Int layout_left :: Int option_prags :: Int }}} We can do quite well; the only functions we can't extract are: begin, pop, multiline_doc_comment, lineCommentToken, nested_doc_comment, withLexedDocType, do_bol, setLine, setFile, warnTab, addTabWarning, lexer, lexTokenAlr, lexToken, lexTokenStream, linePrags, fileHeaderPrags, ignoredPrags, oneWordPrags, twoWordPrags, dispatch_pragmas and known_pragma. Some of these, like lexToken, we can't expect to be able to move to a separate file, as they depend on Alex generated data types and functions (AlexRoutine, alexScanUser). But if we boot-ify lexToken, we can move even more code out. One question, however, is the performance cost of going through an hs-boot file, as these don't inline. I think the constants are fairly safe (inlining opportunities should only occur when we compile Lexer.x, at which point we will have unfoldings for them), but I am less certain about lexToken. Any advice? -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13015 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler