Nim/web/question.txt

===========================================
         Questions and Answers
===========================================


General FAQ
===========


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  What is Nim?
  ------------

  Nim (formerly known as "Nimrod") is a statically typed, imperative programming
  language that tries to give the programmer ultimate power without compromises
  on runtime efficiency.
  This means it focuses on compile-time mechanisms in all their
  various forms. Beneath a nice infix/indentation based syntax with a 
  powerful (AST based, hygienic) macro system lies a semantic model that supports 
  a soft realtime GC on thread local heaps. Asynchronous message passing is used 
  between threads, so no "stop the world" mechanism is necessary. An unsafe 
  shared memory heap is also provided for the increased efficiency that results 
  from that model.


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  Why yet another programming language?
  -------------------------------------

  Nim is one of the very few *programmable* statically typed languages, and 
  one of the even fewer that produces native binaries that require no 
  runtime or interpreter.


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  What have been the major influences in the language's design?
  -------------------------------------------------------------

  The language borrows heavily from (in order of impact): Modula 3, Delphi, Ada,
  C++, Python, Lisp, Oberon.


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  What is Nim's take on concurrency?
  ----------------------------------

  Nim primarily focusses on thread local (and garbage collected) heaps and 
  message passing between threads. Each thread has its own GC, so no 
  "stop the world" mechanism is necessary. An unsafe shared memory heap is also
  provided.

  Future versions will additionally include a GC "per thread group" 
  and Nim's type system will be enhanced to accurately model this shared
  memory heap.


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  How is Nim licensed?
  --------------------

  The Nim compiler and the library are MIT licensed.
  This means that you can use any license for your own programs developed with
  Nim.


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  How stable is Nim?
  ------------------

  The compiler is in development and some important features are still missing.
  However, the compiler is quite stable already: It is able to compile itself 
  and a substantial body of other code. Until version 1.0.0 is released,
  minor incompatibilities with older versions of the compiler will be introduced.


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  How fast is Nim?
  ----------------
  Benchmarks show it to be comparable to C. Some language features (methods, 
  closures, message passing) are not yet as optimized as they could and will be.
  The only overhead Nim has over C is the GC which has been tuned 
  for years but still needs some work.


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  What about JVM/CLR backends?
  ----------------------------

  A JVM backend is almost impossible. The JVM is not expressive enough. It has
  never been designed as a general purpose VM anyway. A CLR backend is possible
  but would require much work. 


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  What about editor support?
  --------------------------

  - Nim IDE: https://github.com/nim-lang/Aporia
  - Emacs: https://github.com/reactormonk/nim-mode
  - Vim: https://github.com/zah/nimrod.vim/
  - Scite: Included
  - Gedit: The `Aporia .lang file <https://github.com/nim-lang/Aporia/blob/master/share/gtksourceview-2.0/language-specs/nim.lang>`_
  - jEdit: https://github.com/exhu/nimrod-misc/tree/master/jedit
  - TextMate: Available in bundle installer (`Repository <https://github.com/textmate/nim.tmbundle>`_)
  - Sublime Text: Available via Package Control (`Repository <https://github.com/Varriount/NimLime>`_)


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  Why is it named ``proc``?
  -------------------------

  *Procedure* used to be the common term as opposed to a *function* which is a
  mathematical entity that has no side effects. It is planned to have ``func``
  as syntactic sugar for ``proc {.noSideEffect.}`` and ``func`` is already a
  keyword.


Compilation FAQ
===============

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  Which option to use for the fastest executable?
  -----------------------------------------------

  For the standard configuration file, ``-d:release`` does the trick.

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  Which option to use for the smallest executable?
  ------------------------------------------------

  For the standard configuration file, ``-d:quick --opt:size`` does the trick.

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  How do I use a different C compiler than the default one?
  ---------------------------------------------------------

  Edit the ``config/nim.cfg`` file.
  Change the value of the ``cc`` variable to one of the following:

  ================  ============================================
  **Abbreviation**  **C/C++ Compiler**
  ================  ============================================
  ``vcc``           Microsoft's Visual C++
  ``gcc``           Gnu C
  ``llvm_gcc``      LLVM-GCC compiler
  ``icc``           Intel C++ compiler
  ``clang``         Clang compiler
  ``ucc``           Generic UNIX C compiler
  ================  ============================================

  Other C compilers are not officially supported, but might work too.

  If your C compiler is not in the above list, try using the
  *generic UNIX C compiler* (``ucc``). If the C compiler needs
  different command line arguments try the ``--passc`` and ``--passl`` switches.