[GHC] #12517: Simplify runghc command line options

[GHC]

#12517: Simplify runghc command line options
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        Reporter:  harendra          |                Owner:  harendra
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  None              |              Version:  8.0.1
      Resolution:                    |             Keywords:  runghc
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by thomie):

 How about this:

 {{{
 runghc [runghc flags] module|filename [GHC flags] [-- [program args]]
 }}}

 Clarification:
 * `runghc -package ..` would be an error, because `-package` is not a
 runghc flag, nor is it a valid module or filename.

 Note that GHC doesn't even support filenames starting with a dash (try
 `ghc -hello.hs`), so I don't understand why the following hack even
 exists:
 {{{
 pastArgs :: String -> Bool
 -- You can use -- to mark the end of the flags, in case you need to use
 -- a file called -foo.hs for some reason. You almost certainly shouldn't,
 -- though.
 pastArgs "--" = True
 pastArgs ('-':_) = False
 pastArgs _       = True
 }}}

 * `"--"` is no longer overloaded. It just separates the GHC flags from the
 program arguments, and to pass program arguments you //have to// use
 `"--"`. This is an improvement, because currently you might think that
 `-v` in `runghc hello.hs -v` is a GHC flag, while it is actually a program
 arguments (and might silently get ignored).

 * `--ghc-arg` can be deprecated

 * Your example would become: `runghc hello.hs -package text-1.2.2.1`

 Are there any drawbacks to this approach (other than also breaking
 backward compatibility)?

 Fwiw: currenly, your example can also be solved without `--ghc-arg` using:
 `runghc -package=text-1.2.2.1 hello.hs`.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12517#comment:2>
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