src/HOL/Library/README.html
author wenzelm
Thu Feb 11 23:00:22 2010 +0100 (2010-02-11)
changeset 35115 446c5063e4fd
parent 31975 366ad09d39ef
child 42062 9fe5daa2e705
permissions -rw-r--r--
modernized translations;
formal markup of @{syntax_const} and @{const_syntax};
minor tuning;
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     7   <title>HOL-Library/README</title>
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    10 <body>
    11 
    12 <h1>HOL-Library: supplemental theories for main Isabelle/HOL</h1>
    13 
    14 This is a collection of generic theories that may be used together
    15 with main Isabelle/HOL.  Note that theory loader path already includes
    16 this directory by default.
    17 
    18 <p>
    19 
    20 Addition of new theories should be done with some care, as the
    21 ``module system'' of Isabelle is rather simplistic.  The following
    22 guidelines may be helpful to achieve maximum re-usability and minimum
    23 clashes with existing developments.
    24 
    25 <dl>
    26 
    27 <dt><strong>Files</strong>
    28 
    29 <dd>Avoid unnecessary scattering of theories over several files.  Use
    30 new-style theories only, as old ones tend to clutter the file space
    31 with separate <tt>.thy</tt> and <tt>.ML</tt> files.
    32 
    33 <dt><strong>Examples</strong>
    34 
    35 <dd>Theories should be as ``generic'' as is sensible.  Unused (or
    36 rather unusable?) theories should be avoided; common applications
    37 should actually refer to the present theory.  Small example uses may
    38 be included in the library as well, but should be put in a separate
    39 theory, such as <tt>Foobar</tt> accompanied by
    40 <tt>Foobar_Examples</tt>.
    41 
    42 <dt><strong>Theory names</strong>
    43 
    44 <dd>The theory loader name space is <em>flat</em>, so use sufficiently
    45 long and descriptive names to reduce the danger of clashes with the
    46 user's own theories.  The convention for theory names is as follows:
    47 <tt>Foobar_Doobar</tt> (this looks best in LaTeX output).
    48 
    49 <dt><strong>Names of logical items</strong>
    50 
    51 <dd>There are separate hierarchically structured name spaces for
    52 types, constants, theorems etc.  Nevertheless, some care should be
    53 taken, as the name spaces are always ``open''.  Use adequate names;
    54 avoid unreadable abbreviations.  The general naming convention is to
    55 separate word constituents by underscores, as in <tt>foo_bar</tt> or
    56 <tt>Foo_Bar</tt> (this looks best in LaTeX output).
    57 
    58 <p>
    59 
    60 Note that syntax is <em>global</em>; qualified names lose syntax on
    61 output.  Do not use ``exotic'' symbols for syntax (such as
    62 <tt>\&lt;oplus&gt;</tt>), but leave these for user applications.
    63 
    64 <dt><strong>Global context declarations</strong>
    65 
    66 <dd>Only items introduced in the present theory should be declared
    67 globally (e.g. as Simplifier rules).  Note that adding and deleting
    68 rules from parent theories may result in strange behavior later,
    69 depending on the user's arrangement of import lists.
    70 
    71 <dt><strong>Mathematical symbols</strong>
    72 
    73 <dd>Non-ASCII symbols should be used as appropriate, with some
    74 care. In particular, avoid unreadable arrows: <tt>==&gt;</tt> should
    75 be preferred over <tt>\&lt;Longrightarrow&gt;</tt>. Use <tt>isabelle
    76 unsymbolize</tt> to clean up the sources.
    77 
    78 <p>
    79 
    80 The following ASCII symbols of HOL should be generally avoided:
    81 <tt>@</tt>, <tt>!</tt>, <tt>?</tt>, <tt>?!</tt>, <tt>%</tt>, better
    82 use <tt>SOME</tt>, <tt>ALL</tt> (or <tt>\&lt;forall&gt;</tt>),
    83 <tt>EX</tt> (or <tt>\&lt;exists&gt;</tt>), <tt>EX!</tt> (or
    84 <tt>\&lt;exists&gt;!</tt>), <tt>\&lt;lambda&gt;</tt>, respectively.
    85 Note that bracket notation <tt>[|&nbsp;|]</tt> looks bad in LaTeX
    86 output.
    87 
    88 <p>
    89 
    90 Some additional mathematical symbols are quite suitable for both
    91 readable sources and the output document:
    92 <tt>\&lt;Inter&gt;</tt>,
    93 <tt>\&lt;Union&gt;</tt>,
    94 <tt>\&lt;and&gt;</tt>,
    95 <tt>\&lt;in&gt;</tt>,
    96 <tt>\&lt;inter&gt;</tt>,
    97 <tt>\&lt;le&gt;</tt>,
    98 <tt>\&lt;not&gt;</tt>,
    99 <tt>\&lt;noteq&gt;</tt>,
   100 <tt>\&lt;notin&gt;</tt>,
   101 <tt>\&lt;or&gt;</tt>,
   102 <tt>\&lt;subset&gt;</tt>,
   103 <tt>\&lt;subseteq&gt;</tt>,
   104 <tt>\&lt;times&gt;</tt>,
   105 <tt>\&lt;union&gt;</tt>.
   106 
   107 <dt><strong>Spacing</strong>
   108 
   109 <dd>Isabelle is able to produce a high-quality LaTeX document from the
   110 theory sources, provided some minor issues are taken care of.  In
   111 particular, spacing and line breaks are directly taken from source
   112 text.  Incidentally, output looks very good if common type-setting
   113 conventions are observed: put a single space <em>after</em> each
   114 punctuation character ("<tt>,</tt>", "<tt>.</tt>", etc.), but none
   115 before it; do not extra spaces inside of parentheses, unless the
   116 delimiters are composed of multiple symbols (as in
   117 <tt>[|&nbsp;|]</tt>); do not attempt to simulate table markup with
   118 spaces, avoid ``hanging'' indentations.
   119 
   120 </dl>
   121 
   122 </body>
   123 </html>