2005-02-18 23:49:00 -05:00
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Rightly or wrongly, the C pre-processor is widely used in Haskell
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source code. It enables conditional compilation for different
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compilers, different versions of the same compiler, and different OS
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platforms. It is also occasionally used for its macro language, which
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can enable certain forms of platform-specific detail-filling, such as
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the tedious boilerplate generation of instance definitions and FFI
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declarations. However, there are two problems with cpp, aside from the
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obvious aesthetic ones:
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* For some Haskell systems, notably Hugs on Windows, a true cpp is
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not available by default.
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* Even for the other Haskell systems, the common cpp provided by the
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2007-06-29 06:59:07 -04:00
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gcc 3.x and 4.x series has changed subtly in ways that are
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incompatible with Haskell's syntax. There have always been
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problems with, for instance, string gaps, and prime characters
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in identifiers. These problems are only going to get worse.
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2005-02-18 23:49:00 -05:00
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2007-06-29 06:59:07 -04:00
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So, it seemed right to provide an alternative to cpp, both more
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compatible with Haskell, and itself written in Haskell so that it
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2005-02-18 23:49:00 -05:00
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can be distributed with compilers. This version of the C pre-processor
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is pretty-much feature-complete, and compatible with the -traditional
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style.
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