theory Intro
imports Base

begin


chapter {* Introduction *}

text {*
  If your next project requires you to program on the ML-level of Isabelle,
  then this tutorial is for you. It will guide you through the first steps of
  Isabelle programming, and also explain tricks of the trade. The best way to
  get to know the ML-level of Isabelle is by experimenting with the many code
  examples included in the tutorial. The code is as far as possible checked
  against recent versions of Isabelle.  If something does not work, then
  please let us know. If you have comments, criticism or like to add to the
  tutorial, feel free---you are most welcome!
*}

section {* Intended Audience and Prior Knowledge *}

text {* 
  This tutorial targets readers who already know how to use Isabelle for
  writing theories and proofs. We also assume that readers are familiar with
  the functional programming language ML, the language in which most of
  Isabelle is implemented. If you are unfamiliar with either of these two
  subjects, you should first work through the Isabelle/HOL tutorial
  \cite{isa-tutorial} or Paulson's book on ML \cite{paulson-ml2}.

*}

section {* Existing Documentation *}

text {*
  
  The following documentation about Isabelle programming already exists (and is
  part of the distribution of Isabelle):

  \begin{description}
  \item[The Implementation Manual] describes Isabelle
  from a high-level perspective, documenting both the underlying
  concepts and some of the interfaces. 

  \item[The Isabelle Reference Manual] is an older document that used
  to be the main reference of Isabelle at a time when all proof scripts 
  were written on the ML-level. Many parts of this manual are outdated 
  now, but some  parts, particularly the chapters on tactics, are still 
  useful.

  \item[The Isar Reference Manual] is also an older document that provides
  material about Isar and its implementation. Some material in it
  is still useful.
  \end{description}

  Then of course there is:

  \begin{description}
  \item[The code] is of course the ultimate reference for how
  things really work. Therefore you should not hesitate to look at the
  way things are actually implemented. More importantly, it is often
  good to look at code that does similar things as you want to do and
  to learn from other people's code.
  \end{description}

*}

section {* Typographic Conventions *}

text {*

  All ML-code in this tutorial is typeset in highlighted boxes, like the following 
  ML-expression:

  \begin{isabelle}
  \begin{graybox}
  \isacommand{ML}~@{text "\<verbopen>"}\isanewline
  \hspace{5mm}@{ML "3 + 4"}\isanewline
  @{text "\<verbclose>"}
  \end{graybox}
  \end{isabelle}
  
  These boxes corresponds to how code can be processed inside the interactive
  environment of Isabelle. It is therefore easy to experiment with what is 
  displayed. However, for better readability we will drop the enclosing 
  \isacommand{ML}~@{text "\<verbopen> \<dots> \<verbclose>"} and just write:


  @{ML [display,gray] "3 + 4"}
  
  Whenever appropriate we also show the response the code 
  generates when evaluated. This response is prefixed with a 
  @{text [quotes] ">"} like:

  @{ML_response [display,gray] "3 + 4" "7"}

  The usual user-level commands of Isabelle are written in bold, for 
  example \isacommand{lemma}, \isacommand{foobar} and so on.  
  We use @{text "$"} to indicate that a command  needs to be run 
  in a Unix-shell, for example

  @{text [display] "$ ls -la"}

  Pointers to further information and Isabelle files are typeset in 
  italic and highlighted as follows:

  \begin{readmore}
  Further information or pointers to files.
  \end{readmore}

*}


end