Updated some documentation.

src/lay/doc/about/about_libraries.xml

@@ -59,8 +59,10 @@
   </ul>
 
   <p>
-  Libraries are loaded on startup and reside in memory while KLayout is running. Therefore, in 
-  order to update a library when the content has changed, KLayout must be restarted.
+  Starting with version 0.25, libraries can be provides through packages. This means, they can be downloaded from some
+  repository and can be managed within the package manager. Library installation is very simple
+  this way. Library deinstallation too. See <link href="/about/packages.xml"/> for details
+  about packages.
   </p>
 
 </doc>

src/lay/doc/about/about_pcells.xml

@@ -60,11 +60,15 @@
   <p>
   PCell's are usually packed in libraries. PCell libraries can be provided as
   shared objects/DLL's (in C++) or as Ruby scripts. Because PCell code is only executed if
-  required, performance is not absolutely mandatory. A Ruby implementation
+  required, performance usally is not the main objective. A Ruby implementation
   will therefore be sufficient in most cases and
-  is a much easier to provide. The Ruby approach also benefits from KLayout's integrated development
+  is a much easier to maintain. The Ruby approach also benefits from KLayout's integrated development
   environment.
   </p>
 
+  <p>
+  For an introduction into PCell programming with Ruby, see <link href="/programming/ruby_pcells.xml"/>.
+  </p>
+
 </doc>
 

src/lay/doc/about/index.xml

@@ -24,6 +24,7 @@
     <topic href="/about/about_libraries.xml"/>
     <topic href="/about/about_pcells.xml"/>
     <topic href="/about/basic_lib.xml"/>
+    <topic href="/about/packages.xml"/>
     <topic href="/about/technology_manager.xml"/>
     <topic href="/about/custom_queries.xml"/>
     <topic href="/about/rba_notation.xml"/>

src/lay/doc/about/macro_editor.xml

@@ -30,6 +30,12 @@
   menu extension. 
   </p>
 
+  <p>
+  Macros can be technology specific. This means, they are packaged with a technology and are associated
+  with the technology in the user interface: if they provide a menu item, this item will only become 
+  visible when the respective technology is active.
+  </p>
+
   <p>
   KLayout also offers an integrated development environment (IDE) that allows editing 
   and debugging of Ruby and Python scripts. It offers a simple debugger with the ability to set breakpoints and 
@@ -70,17 +76,31 @@
       The "macros" or "pymacros" folders in KLayout's user specific application folder. On Unix that is "~/.klayout/macros".
       This is the "local" repository. Any user can store his or her own macros here.
     </li>
+    <li>
+      Plain Ruby or Python files can be kept inside "ruby" and "python" directories next to "macros" and "pymacros". In 
+      contrast to "macros" and "pymacros", the locations of "ruby" and "python" paths are added to the Ruby or Python
+      search paths. This makes those folders useful for keeping plain Ruby or Python libraries. Generic ".lym" files cannot 
+      reside there and those locations are not scanned for autorun macros.
+    </li>
     <li>
       In addition, further repositories can be given on the command line with the "-j" option. This allows
       adding development repositories which are under configuration management and contain the latest code
       for the macros. Those repositories are called "project" repositories.
     </li>
+    <li>
+      Technology folders: each technology folder can carry a "macros" or "pymacros" subfolder where technology-specific
+      macros are kept. See <link href="/about/technology-manager.xml"/> for details about technologies.
+    </li>
+    <li>
+      Macros can be kept in packages and installed from a remote repository. See <link href="/about/packages.xml"/> for 
+      details about packages.
+    </li>
   </ul>
 
   <p>
   The macro IDE will store Python and Ruby macros separately in "macros" and "pymacros" for easier management, 
   but technically these folders are equivalent. KLayout will automatically derive the interpreter 
-  from the context stored in ".lym" files or the file extension (".rb" or ".py").
+  from the context stored in ".lym" files or the file extension (".rb" or ".py"). 
   </p>
 
   <p>

src/lay/doc/about/packages.xml

@@ -0,0 +1,105 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE language SYSTEM "klayout_doc.dtd">
+
+<doc>
+
+  <title>About Packages</title>
+  <keyword>Packages Manager</keyword>
+  <keyword>Packages</keyword>
+  <keyword>Salt</keyword>
+
+  <p>
+  "Salt" is KLayout's package manager which allows selecting and installing packages from a global repository. 
+  Packages make KLayout more tasty. Packages (the "grains") may cover a variety of features:
+  </p>
+
+  <ul>
+    <li>Ruby or Python macros</li>
+    <li>DRC runsets</li>
+    <li>Technologies</li>
+    <li>Fonts for the Basic.TEXT PCell</li>
+    <li>Static layout libraries</li>
+    <li>PCell libraries</li>
+    <li>Code libraries for Ruby and Python</li>
+    <li>Binary extensions</li>
+  </ul>
+
+  <p>
+  Packages can depend on other packages - these are installed automatically if a package requires them and they are not installed yet.
+  </p>
+
+  <p>
+  Packages are identified by name. A package name needs to be unique in the package universe. 
+  You can use a prefixed name like "www.mydomain.org/nameofpackage" to create a non-ambiguous name. 
+  The choice of the prefix is entirely up to you. You can use a domain name that is owned by 
+  yourself for example.
+  </p>
+
+  <p>
+  Packages also come with version information, so KLayout can check for updates and install 
+  them if required. KLayout will assume strict upward compatibility. This specifically 
+  applies to packages that other packages are depending on (such as code libraries). 
+  If you need to change them in a non-backward compatible way, you'd need to provide 
+  a new package with a different name.
+  </p>
+
+  <p>
+  Packages come with some meta data such as authoring information, an optional icon and 
+  screen shot image, license information and more. The more information you provide, the 
+  more useful a package will become.
+  </p>
+
+  <p>
+  The key component for the package repository is the "Salt.Mine" package repository 
+  service (sami.klayout.org). It is a web service that maintains a package list. It 
+  does not host the packages, but stores links to the actual hosting site. In order 
+  to author a package, you need to upload the package to one of the supported host 
+  sites and register your package on the Salt.Mine page. Registration is a simple 
+  process and the only information required is the link to your host site and a mail 
+  account for confirmation.
+  </p>
+
+  <p>
+  Currently, GitHub is supported as a host site. As a package author you'll need a GitHub 
+  account and open a project for your package there. GitHub acts both as a code repository 
+  for your development and as a deployment platform. KLayout can download packages directly 
+  from your GitHub project's master or a release tag.
+  </p>
+
+  <h2>The DNA</h2>
+
+  <p>
+  Technically, packages are folders stored below the "salt" folder within KLayout's home 
+  path. Prefixed packages are kept in sub-folders named after the prefix. Each package 
+  directory contains a description file called "grain.xml" and the files that make up the 
+  package. For Ruby macros, for example, the package folder will contain a "macros" 
+  sub-folder. Basically, packages do not require to be of a specific kind - they can 
+  provide technology information, DRC scripts and macros in the same package. In this 
+  example, the will be a "tech", "drc" and "macros" sub-folder with the corresponding 
+  files. KLayout will scan the package folders for useful files and load them automatically.
+  </p>
+
+  <p>
+  Packages are published on the Salt.Mine server. This is a web service that delivers a 
+  complete list of packages plus a little meta data such as current version, the icon 
+  and a brief description. KLayout will download this list from 
+  "http://sami.klayout.org/repository.xml" by default. You can set the KLAYOUT_SALT_MINE 
+  environment variable to a different URL which makes KLayout use another repository 
+  service, i.e. one inside your own organisation. This service can be any HTTP server 
+  that delivers a package list in the same format than the Salt.Mine package service.
+  </p>
+
+  <p>
+  When installing a package, KLayout will simply download the files from the URL given 
+  in the package list. KLayout employs the WebDAV protocol to download the files. 
+  This protocol is spoken by Subversion and GitHub with the subversion bridge. The 
+  latter requires a simple translation of the original Git URL's to obtain the 
+  subversion equivalent.
+  </p>
+
+  <p>
+  For package development you utilize KLayout to initialize and edit the files inside 
+  the package folder or populate the folder manually.
+  </p>
+
+</doc>

src/lay/doc/about/technology_manager.xml

@@ -94,9 +94,8 @@
   </p>
 
   <p>
-  Macros and DRC scripts associated with a technology are shown in the technology manager, but
-  cannot be edited there. The right place to edit, run or debug macros or DRC script is the 
-  macro development environment. To open the macro development environment choose "Macros/Macro Development".
+  Macros and DRC scripts associated with a technology are shown in the technology manager. To edit
+  or debug scripts of macros, use the macro development environment ("Macros/Macro Development").
   If a technology has a macros or DRC scripts folder, the macro or DRC scripts tree in the
   development environment will show a corresponding top-level branch for that technology.
   </p>

src/lay/layHelpResources.qrc

@@ -134,6 +134,7 @@
         <file alias="drc_ref_layer.xml">doc/about/drc_ref_layer.xml</file>
         <file alias="drc_ref_source.xml">doc/about/drc_ref_source.xml</file>
         <file alias="drc_ref_global.xml">doc/about/drc_ref_global.xml</file>
+        <file alias="packages.xml">doc/about/packages.xml</file>
     </qresource>
     <qresource prefix="/help/manual">
         <file alias="adjust_origin.xml">doc/manual/adjust_origin.xml</file>