[GHC] #13844: Surprising behavior with CPP extension
#13844: Surprising behavior with CPP extension -------------------------------------+------------------------------------- Reporter: deech | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.2 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: -------------------------------------+------------------------------------- The CPP language extension performs macro substitutions in Haskell comments. I see why it does but it seems like eliding the comments before pre-processing would be less surprising. Eg. compiling: {{{#!hs {-# LANGUAGE CPP -#} -- | Some folder foo/bar/* }}} gives the error: {{{ error: unterminated comment -- | Some folder foo/bar/* }}} because the `/*` in the comment is interpreted as starting a C comment. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13844 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13844: Surprising behavior with CPP extension -------------------------------------+------------------------------------- Reporter: deech | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by bgamari): Mmm, this is unfortunate. Eliding comments prior to pre-processing is not trivial but could be done. We would need a simple parser which would also produce `#line` pragmas to ensure that line information is correct in the post-CPP parse. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13844#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13844: Surprising behavior with CPP extension -------------------------------------+------------------------------------- Reporter: deech | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by pggiarrusso): Docs for cpphs say "Macros are never expanded within Haskell comments": http://projects.haskell.org/cpphs/#diff. Any chance that helps? -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13844#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13844: Surprising behavior with CPP extension -------------------------------------+------------------------------------- Reporter: deech | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by RyanGlScott): `cpphs` works very differently than `cpp` internally, so I'd be surprised if the techniques that `cpphs` are using to accomplish that would be applicable to `cpp`. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13844#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13844: Surprising behavior with CPP extension -------------------------------------+------------------------------------- Reporter: deech | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by hvr): Fwiw, this is old news. Here's an old proposal of mine that could lead us out of this misery: Proposal/NativeCpp Just needs somebody to implement it... :-) -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13844#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
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