<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html> <head> <title></title> <link rel="stylesheet" media="screen" type="text/css" href="./style.css" /> <link rel="stylesheet" media="screen" type="text/css" href="./design.css" /> <link rel="stylesheet" media="print" type="text/css" href="./print.css" /> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> </head> <body> <div class="table sectionedit629"><table class="inline"> <tr class="row0"> <td class="col0 leftalign"> « <a href="geda-gschem_ug-stroke.html" class="wikilink1" title="geda-gschem_ug-stroke.html">Mouse gesture support</a> </td><td class="col1 centeralign"> <strong><a href="geda-gschem_ug.html" class="wikilink1" title="geda-gschem_ug.html">gEDA gschem User Guide</a></strong> </td><td class="col2 rightalign"> <a href="geda-gschem_ug.html" class="wikilink1" title="geda-gschem_ug.html">Contents</a> » </td> </tr> </table></div> <!-- EDIT629 TABLE [1-125] --> <h2 class="sectionedit630"><a name="extending_gschem" id="extending_gschem">Extending gschem</a></h2> <div class="level2"> <p> Since the gschem <a href="geda-gschem_ug-config.html" class="wikilink1" title="geda-gschem_ug-config.html">configuration files</a> are Scheme scripts, they provide a way to load additional capabilities into gschem by defining new functions that manipulate objects and pages. </p> <p> gschem (and other gEDA/gaf tools such as <a href="geda-gnetlist_ug.html" class="wikilink1" title="geda-gnetlist_ug.html">gnetlist</a>) use <a href="http://www.gnu.org/s/guile/" class="urlextern" title="http://www.gnu.org/s/guile/" rel="nofollow">Guile Scheme</a> to provide Scheme scripting capabilities, and all of the features of Guile are available to use. The <em>Guile Reference Manual</em> is available as an Info manual (<code>info guile</code> on most systems), or <a href="http://www.gnu.org/software/guile/docs/docs.html" class="urlextern" title="http://www.gnu.org/software/guile/docs/docs.html" rel="nofollow">on the Guile website</a>. </p> <p> A collection of modules is provided for accessing and modifying gEDA objects and pages, called the gEDA Scheme <acronym title="Application Programming Interface">API</acronym>. The <em>gEDA Scheme Reference Manual</em> is also available as an Info manual (<code>info geda-scheme</code>). </p> </div> <!-- EDIT630 SECTION "Extending gschem" [127-998] --> <h3 class="sectionedit631"><a name="adding_an_action" id="adding_an_action">Adding an action</a></h3> <div class="level3"> <p> Actions are thunks, i.e. Scheme procedures that take no arguments. For gschem to be able to find them, they must be defined in the top-level <a href="http://www.gnu.org/software/guile/manual/html_node/Modules.html" class="urlextern" title="http://www.gnu.org/software/guile/manual/html_node/Modules.html" rel="nofollow">module</a>, so you must do one of the following: </p> <ul> <li class="level1"><div class="li"> define the procedure directly in one of your configuration files;</div> </li> <li class="level1"><div class="li"> define the procedure in a Scheme file loaded (using <code>load</code>) from one of your configuration files;</div> </li> <li class="level1"><div class="li"> or export the procedure in a Guile module which you load (with <code>use-modules</code>) from your configuration files.</div> </li> </ul> <p> You can then bind the procedure to a keystroke as normal with <code>global-set-key</code>. </p> </div> <!-- EDIT631 SECTION "Adding an action" [999-1655] --> <h3 class="sectionedit632"><a name="hooking_into_built-in_actions" id="hooking_into_built-in_actions">Hooking into built-in actions</a></h3> <div class="level3"> <p> gschem allows you to register functions, called <em>hooks</em>, to be executed when a user executes a built-in function. These are provided by the <code>(gschem hook)</code> Guile module. For more information, see the <em>Hooks</em> page in the <em>gEDA Scheme Reference Manual</em>. </p> </div> <!-- EDIT632 SECTION "Hooking into built-in actions" [1656-1958] --> <h3 class="sectionedit633"><a name="procedures_for_extension_writers" id="procedures_for_extension_writers">Procedures for extension writers</a></h3> <div class="level3"> <p> In addition to the gEDA Scheme <acronym title="Application Programming Interface">API</acronym> functions, gschem provides some utility procedures for extension writers. </p> <p> <p><div class="noteimportant">The functions described in this section are not guaranteed to remain stable from one release of gEDA/gaf to another. For longer-term stability, use only the gEDA Scheme <acronym title="Application Programming Interface">API</acronym>. </div></p> </p> <div class="table sectionedit634"><table class="inline"> <tr class="row0"> <th class="col0 leftalign"> Function </th><th class="col1 leftalign"> Description </th> </tr> <tr class="row1"> <td class="col0"> <code>gschem-print</code> </td><td class="col1 leftalign"> Export PostScript (see <a href="geda-gschem_ug-printing.html" class="wikilink1" title="geda-gschem_ug-printing.html">Printing</a>) to the output filename specified with the <code>-o</code> <a href="geda-gschem_ug-command_line.html" class="wikilink1" title="geda-gschem_ug-command_line.html">command-line option</a>, or the default PostScript filename if no option was given. </td> </tr> <tr class="row2"> <td class="col0"> <code>gschem-postscript FILENAME</code> </td><td class="col1 leftalign"> Export PostScript to <code>FILENAME</code>. </td> </tr> <tr class="row3"> <td class="col0"> <code>gschem-image FILENAME</code> </td><td class="col1 leftalign"> Export an image (see <a href="geda-gschem_ug-exporting.html" class="wikilink1" title="geda-gschem_ug-exporting.html">Exporting images</a>) to the output filename specified with the <code>-o</code> command-line option, or to <code>FILENAME</code> if no option was given. </td> </tr> <tr class="row4"> <td class="col0 leftalign"> <code>gschem-exit</code> </td><td class="col1 leftalign"> Exit gschem immediately. <strong>Warning:</strong> if the user has unsaved changes, he will not be given the opportunity to save them. </td> </tr> <tr class="row5"> <td class="col0 leftalign"> <code>gschem-log MSG</code> </td><td class="col1 leftalign"> Write <code>MSG</code> to the gschem log. </td> </tr> <tr class="row6"> <td class="col0 leftalign"> <code>gschem-msg MSG</code> </td><td class="col1 leftalign"> Display a message dialog to the user with the text <code>MSG</code>. </td> </tr> <tr class="row7"> <td class="col0 leftalign"> <code>gschem-confirm MSG</code> </td><td class="col1 leftalign"> Display a confirmation dialog to the user, with “Yes” and “No” buttons and the text <code>MSG</code>. Return <code>#t</code> if the user selects “Yes”, and <code>#f</code> otherwise. </td> </tr> <tr class="row8"> <td class="col0 leftalign"> <code>gschem-filesel MSG TEMPL FLAGS</code> </td><td class="col1"> Display a file selector dialog, with <code>MSG</code> in the title and the default filename <code>TEMPL</code>. The <code>FLAGS</code> control the file selector behavior, and should be a list of strings. The following strings can be provided in the <code>FLAGS</code>: <code>“may_exist”</code> if the file selected is permitted to already exist; <code>“must_exist”</code> if the file selected must already exist; <code>“must_not_exist”</code> if the file selected must <em>not</em> already exist; <code>“save”</code> to show a “Save file…” dialog; <code>“open”</code> to show an “Open file…” dialog. </td> </tr> </table></div> <!-- EDIT634 TABLE [2312-3885] --> </div> <!-- EDIT633 SECTION "Procedures for extension writers" [1959-] --></body> </html>
