/usr/lib/swi-prolog/doc/Manual/extensions.html

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<h1 id="sec:extensions"><a id="sec:5"><span class="sec-nr">5</span> <span class="sec-title">SWI-Prolog 
extensions</span></a></h1>

<a id="sec:extensions"></a>

<p>This chapter describes extensions to the Prolog language introduced 
with SWI-Prolog version&nbsp;7. The changes bring more modern 
syntactical conventions to Prolog such as key-value maps, called <em>dicts</em> 
as primary citizens and a restricted form of <em>functional notation</em>. 
They also extend Prolog basic types with strings, providing a natural 
notation to textual material as opposed to identifiers (atoms) and 
lists.

<p>These extensions make the syntax more intuitive to new users, 
simplify the integration of domain specific languages (DSLs) and 
facilitate a more natural Prolog representation for popular exchange 
languages such as XML and JSON.

<p>While many programs run unmodified in SWI-Prolog version&nbsp;7, 
especially those that pass double quoted strings to general purpose list 
processing predicates require modifications. We provide a tool (<a id="idx:liststrings0:1443"></a><a class="pred" href="strings.html#list_strings/0">list_strings/0</a>) 
that we used to port a huge code base in half a day.

<p>
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<h2>Section Index</h2>

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<hr>
<div class="toc">
<div class="toc-h2"><a class="sec" href="ext-lists.html"><span class="sec-nr">5.1</span> <span class="sec-title">Lists 
are special</span></a></div>
<div class="toc-h3"><a class="sec" href="ext-lists.html#sec:5.1.1"><span class="sec-nr">5.1.1</span> <span class="sec-title">Motivating 
' ' and[]for lists</span></a></div>
<div class="toc-h2"><a class="sec" href="strings.html"><span class="sec-nr">5.2</span> <span class="sec-title">The 
string type and its double quoted syntax</span></a></div>
<div class="toc-h3"><a class="sec" href="strings.html#sec:5.2.1"><span class="sec-nr">5.2.1</span> <span class="sec-title">Predicates 
that operate on strings</span></a></div>
<div class="toc-h3"><a class="sec" href="strings.html#sec:5.2.2"><span class="sec-nr">5.2.2</span> <span class="sec-title">Representing 
text: strings, atoms and code lists</span></a></div>
<div class="toc-h3"><a class="sec" href="strings.html#sec:5.2.3"><span class="sec-nr">5.2.3</span> <span class="sec-title">Adapting 
code for double quoted strings</span></a></div>
<div class="toc-h3"><a class="sec" href="strings.html#sec:5.2.4"><span class="sec-nr">5.2.4</span> <span class="sec-title">Why 
has the representation of double quoted text changed?</span></a></div>
<div class="toc-h2"><a class="sec" href="ext-syntax.html"><span class="sec-nr">5.3</span> <span class="sec-title">Syntax 
changes</span></a></div>
<div class="toc-h3"><a class="sec" href="ext-syntax.html#sec:5.3.1"><span class="sec-nr">5.3.1</span> <span class="sec-title">Operators 
and quoted atoms</span></a></div>
<div class="toc-h3"><a class="sec" href="ext-syntax.html#sec:5.3.2"><span class="sec-nr">5.3.2</span> <span class="sec-title">Compound 
terms with zero arguments</span></a></div>
<div class="toc-h3"><a class="sec" href="ext-syntax.html#sec:5.3.3"><span class="sec-nr">5.3.3</span> <span class="sec-title">Block 
operators</span></a></div>
<div class="toc-h2"><a class="sec" href="dicts.html"><span class="sec-nr">5.4</span> <span class="sec-title">Dicts: 
structures with named arguments</span></a></div>
<div class="toc-h3"><a class="sec" href="dicts.html#sec:5.4.1"><span class="sec-nr">5.4.1</span> <span class="sec-title">Functions 
on dicts</span></a></div>
<div class="toc-h4"><a class="sec" href="dicts.html#sec:5.4.1.1"><span class="sec-nr">5.4.1.1</span> <span class="sec-title">User 
defined functions on dicts</span></a></div>
<div class="toc-h4"><a class="sec" href="dicts.html#sec:5.4.1.2"><span class="sec-nr">5.4.1.2</span> <span class="sec-title">Predefined 
functions on dicts</span></a></div>
<div class="toc-h3"><a class="sec" href="dicts.html#sec:5.4.2"><span class="sec-nr">5.4.2</span> <span class="sec-title">Predicates 
for managing dicts</span></a></div>
<div class="toc-h4"><a class="sec" href="dicts.html#sec:5.4.2.1"><span class="sec-nr">5.4.2.1</span> <span class="sec-title">Destructive 
assignment in dicts</span></a></div>
<div class="toc-h3"><a class="sec" href="dicts.html#sec:5.4.3"><span class="sec-nr">5.4.3</span> <span class="sec-title">When 
to use dicts?</span></a></div>
<div class="toc-h3"><a class="sec" href="dicts.html#sec:5.4.4"><span class="sec-nr">5.4.4</span> <span class="sec-title">A 
motivation for dicts as primary citizens</span></a></div>
<div class="toc-h3"><a class="sec" href="dicts.html#sec:5.4.5"><span class="sec-nr">5.4.5</span> <span class="sec-title">Implementation 
notes about dicts</span></a></div>
<div class="toc-h2"><a class="sec" href="ext-integration.html"><span class="sec-nr">5.5</span> <span class="sec-title">Integration 
of strings and dicts in the libraries</span></a></div>
<div class="toc-h3"><a class="sec" href="ext-integration.html#sec:5.5.1"><span class="sec-nr">5.5.1</span> <span class="sec-title">Dicts 
and option processing</span></a></div>
<div class="toc-h3"><a class="sec" href="ext-integration.html#sec:5.5.2"><span class="sec-nr">5.5.2</span> <span class="sec-title">Dicts 
in core data structures</span></a></div>
<div class="toc-h3"><a class="sec" href="ext-integration.html#sec:5.5.3"><span class="sec-nr">5.5.3</span> <span class="sec-title">Dicts, 
strings and XML</span></a></div>
<div class="toc-h3"><a class="sec" href="ext-integration.html#sec:5.5.4"><span class="sec-nr">5.5.4</span> <span class="sec-title">Dicts, 
strings and JSON</span></a></div>
<div class="toc-h3"><a class="sec" href="ext-integration.html#sec:5.5.5"><span class="sec-nr">5.5.5</span> <span class="sec-title">Dicts, 
strings and HTTP</span></a></div>
<div class="toc-h2"><a class="sec" href="ext-issues.html"><span class="sec-nr">5.6</span> <span class="sec-title">Remaining 
issues</span></a></div>
</div>
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swi-prolog-nox 7.2.3-2 / usr / lib / swi-prolog / doc / Manual / extensions.html
