#4372: Extending quasiquotation support -------------------------------------+------------------------------------- Reporter: simonpj | Owner: Type: bug | Status: new Priority: normal | Milestone: 7.12.1 Component: Template Haskell | Version: 6.12.3 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: None/Unknown | Unknown/Multiple Blocked By: | Test Case: Related Tickets: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- Comment (by songzh): Replying to [comment:19 gershomb]:

At this point I consider this a "nice idea" but I'm not sure how to modify the parser to handle it within the many grammatical constraints we already have. The somewhat clunky syntax that was pointed out by Simon upthread is actually adequate for this. This, for example is the style adopted by Manuel's language-c-inline:

I am sorry for not being a GHC developer, I will try to be one. I have skimmed the parser in the source code. My understanding is that the quoters do not need to be all kinds of expressions since allowing only function application will be more than enough. If expression like CondE, MultiIfE, DoE, CompE should be not allowed in quoter position, the guarded expression and other syntax problem will vanish. For achieving this, maybe a specific parser for quoter position is needed. I am just blind guessing here.

{{{ nslog msg = $(objc ['msg :> ''String] (void [cexp| NSLog(@"Here is a message from Haskell: %@", msg) |])) }}}

Here, we use the quasiquoter to capture the expression, and then embed

that quasiquoted expression itself within a TH block, in order to pass in additional information during codegen.

If a lighter-weight syntax was possible, I'd remain all for it. But, I

honestly can't think how to provide it given the constraints we have -- my patch at the time didn't really solve the problem, and I haven't had any better ideas since :-) I will look into the c-language package and your patch. Thanks. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/4372#comment:20 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler