mirror of
https://github.com/ganelson/inform.git
synced 2024-07-05 08:34:22 +03:00
145 lines
9.7 KiB
HTML
145 lines
9.7 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
|
<html>
|
|
<head>
|
|
<title>What This Module Does</title>
|
|
<link href="../docs-assets/Breadcrumbs.css" rel="stylesheet" rev="stylesheet" type="text/css">
|
|
<meta name="viewport" content="width=device-width initial-scale=1">
|
|
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
|
|
<meta http-equiv="Content-Language" content="en-gb">
|
|
|
|
<link href="../docs-assets/Contents.css" rel="stylesheet" rev="stylesheet" type="text/css">
|
|
<link href="../docs-assets/Progress.css" rel="stylesheet" rev="stylesheet" type="text/css">
|
|
<link href="../docs-assets/Navigation.css" rel="stylesheet" rev="stylesheet" type="text/css">
|
|
<link href="../docs-assets/Fonts.css" rel="stylesheet" rev="stylesheet" type="text/css">
|
|
<link href="../docs-assets/Base.css" rel="stylesheet" rev="stylesheet" type="text/css">
|
|
<link href="../docs-assets/Colours.css" rel="stylesheet" rev="stylesheet" type="text/css">
|
|
|
|
</head>
|
|
<body class="commentary-font">
|
|
<nav role="navigation">
|
|
<h1><a href="../index.html">
|
|
<img src="../docs-assets/Inform.png" height=72">
|
|
</a></h1>
|
|
<ul><li><a href="../compiler.html">compiler tools</a></li>
|
|
<li><a href="../other.html">other tools</a></li>
|
|
<li><a href="../extensions.html">extensions and kits</a></li>
|
|
<li><a href="../units.html">unit test tools</a></li>
|
|
</ul><h2>Compiler Webs</h2><ul>
|
|
<li><a href="../inbuild/index.html">inbuild</a></li>
|
|
<li><a href="../inform7/index.html">inform7</a></li>
|
|
<li><a href="../inter/index.html">inter</a></li>
|
|
</ul><h2>Inbuild Modules</h2><ul>
|
|
<li><a href="../supervisor-module/index.html">supervisor</a></li>
|
|
</ul><h2>Inform7 Modules</h2><ul>
|
|
<li><a href="../core-module/index.html">core</a></li>
|
|
<li><a href="../assertions-module/index.html">assertions</a></li>
|
|
<li><a href="../values-module/index.html">values</a></li>
|
|
<li><a href="../knowledge-module/index.html">knowledge</a></li>
|
|
<li><a href="../imperative-module/index.html">imperative</a></li>
|
|
<li><a href="../runtime-module/index.html">runtime</a></li>
|
|
<li><a href="index.html"><span class="selectedlink">if</span></a></li>
|
|
<li><a href="../multimedia-module/index.html">multimedia</a></li>
|
|
<li><a href="../index-module/index.html">index</a></li>
|
|
</ul><h2>Inter Modules</h2><ul>
|
|
<li><a href="../bytecode-module/index.html">bytecode</a></li>
|
|
<li><a href="../building-module/index.html">building</a></li>
|
|
<li><a href="../codegen-module/index.html">codegen</a></li>
|
|
</ul><h2>Services</h2><ul>
|
|
<li><a href="../arch-module/index.html">arch</a></li>
|
|
<li><a href="../calculus-module/index.html">calculus</a></li>
|
|
<li><a href="../html-module/index.html">html</a></li>
|
|
<li><a href="../inflections-module/index.html">inflections</a></li>
|
|
<li><a href="../kinds-module/index.html">kinds</a></li>
|
|
<li><a href="../linguistics-module/index.html">linguistics</a></li>
|
|
<li><a href="../problems-module/index.html">problems</a></li>
|
|
<li><a href="../syntax-module/index.html">syntax</a></li>
|
|
<li><a href="../words-module/index.html">words</a></li>
|
|
<li><a href="../../../inweb/docs/foundation-module/index.html">foundation</a></li>
|
|
|
|
</ul>
|
|
</nav>
|
|
<main role="main">
|
|
<!--Weave of 'What This Module Does' generated by Inweb-->
|
|
<div class="breadcrumbs">
|
|
<ul class="crumbs"><li><a href="../index.html">Home</a></li><li><a href="../compiler.html">Inform7</a></li><li><a href="index.html">if</a></li><li><a href="index.html#P">Preliminaries</a></li><li><b>What This Module Does</b></li></ul></div>
|
|
<p class="purpose">An overview of the if module's role and abilities.</p>
|
|
|
|
<ul class="toc"><li><a href="P-wtmd.html#SP1">§1. Prerequisites</a></li><li><a href="P-wtmd.html#SP2">§2. So many plugins</a></li></ul><hr class="tocbar">
|
|
|
|
<p class="commentary firstcommentary"><a id="SP1" class="paragraph-anchor"></a><b>§1. Prerequisites. </b>The if module is a part of the Inform compiler toolset. It is presented as a
|
|
literate program or "web". Before diving in:
|
|
</p>
|
|
|
|
<ul class="items"><li>(a) It helps to have some experience of reading webs: see <a href="../../../inweb/docs/index.html" class="internal">inweb</a> for more.
|
|
</li><li>(b) The module is written in C, in fact ANSI C99, but this is disguised by the
|
|
fact that it uses some extension syntaxes provided by the <a href="../../../inweb/docs/index.html" class="internal">inweb</a> literate
|
|
programming tool, making it a dialect of C called InC. See <a href="../../../inweb/docs/index.html" class="internal">inweb</a> for
|
|
full details, but essentially: it's C without predeclarations or header files,
|
|
and where functions have names like <span class="extract"><span class="extract-syntax">Tags::add_by_name</span></span> rather than just <span class="extract"><span class="extract-syntax">add_by_name</span></span>.
|
|
</li><li>(c) This module uses other modules drawn from the <a href="../compiler.html" class="internal">compiler</a>, and also
|
|
uses a module of utility functions called <a href="../../../inweb/docs/foundation-module/index.html" class="internal">foundation</a>.
|
|
For more, see <a href="../../../inweb/docs/foundation-module/P-abgtf.html" class="internal">A Brief Guide to Foundation (in foundation)</a>.
|
|
</li></ul>
|
|
<p class="commentary firstcommentary"><a id="SP2" class="paragraph-anchor"></a><b>§2. So many plugins. </b>This module consists entirely of plugins, and when they are all inactive,
|
|
as for example with a Basic Inform project, it's as if the module does not exist
|
|
at all: it does nothing.
|
|
</p>
|
|
|
|
<p class="commentary">The module is divided into four substantive parts, which form Chapters 2 to 5,
|
|
and are largely independent of each other:
|
|
</p>
|
|
|
|
<ul class="items"><li>● <a href="2-bd.html" class="internal">Chapter 2: Bibliographic Data</a> is a single plugin, "bibliographic data".
|
|
This manages metadata on projects, notably the Interactive Fiction ID, and
|
|
follows a number of Internet standards for such things. <a href="2-ri.html" class="internal">Release Instructions</a>
|
|
collates release details included in the source text, and acts as a bridge to
|
|
the releasing agent <a href="../inblorb/index.html" class="internal">inblorb</a>.
|
|
</li><li>● <a href="3-sm.html" class="internal">Chapter 3: Space and Time</a>, by contrast, is made up of many individual
|
|
plugins, which can independently be active or not: collectively they form the
|
|
usual model world for interactive fiction, but it's possible, for example,
|
|
to remove the concept of a geographical map, or of scenes, and still have
|
|
the rest.
|
|
</li><li>● <a href="4-ap.html" class="internal">Chapter 4: Actions</a> is the single plugin "actions", which provides a
|
|
framework for how agents in the world model can perform simple tasks such as
|
|
picking things up, or going from place to place.
|
|
</li><li>● <a href="5-pp.html" class="internal">Chapter 5: Command Parser</a> is the single plugin "parsing", and
|
|
provides for command parsing. Projects using other mechanisms for having
|
|
the reader interact with them do not need this, and can deactivate the plugin.
|
|
</li></ul>
|
|
<p class="commentary firstcommentary"><a id="SP3" class="paragraph-anchor"></a><b>§3. </b>Grammar is organised in a three-level hierarchy:
|
|
</p>
|
|
|
|
<ul class="items"><li>(a) A command grammar (CG) is a small independent grammar of alternative
|
|
formulations for some concept: for instance, the possible commands beginning
|
|
TAKE, or the possible verbal forms of numbers. Each CG is a list of CGLs, and
|
|
an individual CGL must belong to exactly one CG. There are five different
|
|
types of CG, differentiated mostly by the purpose to which the CG is put:
|
|
<ul class="items"><li>(1) <span class="extract"><span class="extract-syntax">CG_IS_COMMAND</span></span>. An imperative verbal command at run-time.
|
|
</li><li>(2) <span class="extract"><span class="extract-syntax">CG_IS_TOKEN</span></span>. A square-bracketed token in other grammar.
|
|
</li><li>(3) <span class="extract"><span class="extract-syntax">CG_IS_SUBJECT</span></span>. A noun phrase at run time: a name for an object.
|
|
</li><li>(4) <span class="extract"><span class="extract-syntax">CG_IS_VALUE</span></span>. A noun phrase at run time: a name for a value.
|
|
</li><li>(5) <span class="extract"><span class="extract-syntax">CG_IS_CONSULT</span></span>. A pattern to match in part of a command (such as "consult").
|
|
</li><li>(6) <span class="extract"><span class="extract-syntax">CG_IS_PROPERTY_NAME</span></span>. A noun phrase at run time: a name for one
|
|
possibility for an either/or property, say "open" or "fixed in place".
|
|
</li></ul>
|
|
<li>(b) A grammar line (CGL) is a single possibility within a CG: for
|
|
example, the line matching <span class="extract"><span class="extract-syntax">"take [something]"</span></span> in the CG for the TAKE
|
|
command. Each CGL is a list of tokens, and an individual token must belong
|
|
to exactly one CGL.
|
|
</li><li>(c) A grammar token (GTOK) is a single particle of a CGL: for
|
|
example, <span class="extract"><span class="extract-syntax">'take'</span></span> and <span class="extract"><span class="extract-syntax">something</span></span> are tokens.
|
|
</li></ul>
|
|
<p class="commentary">The picture is not quite so hierarchical as it looks, though, because
|
|
a CG naming a token can be used as a token inside other CGs. We need to
|
|
be careful that this does not lead to infinite regress: see below.
|
|
</p>
|
|
|
|
<nav role="progress"><div class="progresscontainer">
|
|
<ul class="progressbar"><li class="progressprevoff">❮</li><li class="progresscurrentchapter">P</li><li class="progresscurrent">wtmd</li><li class="progresschapter"><a href="1-im.html">1</a></li><li class="progresschapter"><a href="2-bd.html">2</a></li><li class="progresschapter"><a href="3-sm.html">3</a></li><li class="progresschapter"><a href="4-ap.html">4</a></li><li class="progresschapter"><a href="5-pp.html">5</a></li><li class="progressnext"><a href="1-im.html">❯</a></li></ul></div>
|
|
</nav><!--End of weave-->
|
|
|
|
</main>
|
|
</body>
|
|
</html>
|
|
|