From f8c029f6c9837d37ca1a668546ea5272bc746fbb Mon Sep 17 00:00:00 2001
From: rillig <rillig@pkgsrc.org>
Date: Tue, 23 May 2006 08:10:37 +0000
Subject: The "future directions" chapter gives a vision of what pkglint may do
 if I find too much time.

---
 pkgtools/pkglint/files/doc/Makefile        |  3 +-
 pkgtools/pkglint/files/doc/chap.future.xml | 48 ++++++++++++++++++++++++++++++
 pkgtools/pkglint/files/doc/pkglint.xml     |  4 ++-
 3 files changed, 53 insertions(+), 2 deletions(-)
 create mode 100644 pkgtools/pkglint/files/doc/chap.future.xml

(limited to 'pkgtools')

diff --git a/pkgtools/pkglint/files/doc/Makefile b/pkgtools/pkglint/files/doc/Makefile
index 3c8a67267a7..d36715f890d 100644
--- a/pkgtools/pkglint/files/doc/Makefile
+++ b/pkgtools/pkglint/files/doc/Makefile
@@ -1,4 +1,4 @@
-# $NetBSD: Makefile,v 1.2 2006/02/27 02:01:04 rillig Exp $
+# $NetBSD: Makefile,v 1.3 2006/05/23 08:10:37 rillig Exp $
 #
 
 XMLDOCS+=	pkglint.xml
@@ -7,6 +7,7 @@ XMLDOCS+=	chap.defs.xml
 XMLDOCS+=	chap.types.xml
 XMLDOCS+=	chap.code.xml
 XMLDOCS+=	chap.statemachines.xml
+XMLDOCS+=	chap.future.xml
 
 IMAGES+=	statemachine.patch.png
 IMAGES+=	statemachine.shellcmd.png
diff --git a/pkgtools/pkglint/files/doc/chap.future.xml b/pkgtools/pkglint/files/doc/chap.future.xml
new file mode 100644
index 00000000000..8700a4395da
--- /dev/null
+++ b/pkgtools/pkglint/files/doc/chap.future.xml
@@ -0,0 +1,48 @@
+<!-- $NetBSD: chap.future.xml,v 1.1 2006/05/23 08:10:37 rillig Exp $ -->
+
+<chapter id="future">
+<title>Future directions</title>
+
+<sect1 id="future.tokenize">
+<title>Tokenizing the input</title>
+
+	<para>For providing more exact diagnostics, it would be nice if
+	&pkglint; could point the user to the exact character position
+	of the smallest problematic text in a file. To do this, the
+	file's contents has to be splitted into tokens.</para>
+
+	<para>Doing this is nontrivial, since the tokenizing scheme
+	depends on the context in which the tokens are used. For
+	example, the <varname>COMMENT</varname> variable may contain
+	arbitrary characters (including <literal>'</literal> and
+	<literal>"</literal>), whereas in many other contexts these are
+	parts of quoted shell words.</para>
+
+</sect1>
+<sect1 id="future.ast">
+<title>Working on abstract syntax trees (AST)</title>
+
+	<para>When the tokenizing above is done, the tokens could be
+	parsed by a grammar to form abstract syntax trees. These would
+	consist mainly of function application so that pkglint can infer
+	types and valid values over these trees. The following functions
+	are likely to appear.</para>
+
+	<table id="future.ast.func">
+	<title>Functions in the abstract syntax trees</title>
+	<tgroup cols="2">
+	<thead><row><entry>Function</entry><entry>Purpose</entry></row></thead>
+	<tbody>
+	<row><entry><function>quote</function>(Val)</entry><entry>The <literal>:Q</literal> modifier</entry></row>
+	<row><entry><function>append</function>(Val, Val)</entry><entry>The <literal>+=</literal> operator</entry></row>
+	<row><entry><function>concat</function>(Val, Val)</entry><entry>The direct concatenation of two values</entry></row>
+	<row><entry><function>subst</function>(Val, Subst)</entry><entry>The <literal>:S</literal> and <literal>:C</literal> modifiers</entry></row>
+	<row><entry><function>shell</function>(Val)</entry><entry>The <literal>!=</literal> operator and the <literal>:sh</literal> modifier</entry></row>
+	<row><entry><function>literal</function>(Val)</entry><entry>Introduces literal values</entry></row>
+	</tbody>
+	</tgroup>
+	</table>
+
+</sect1>
+
+</chapter>
diff --git a/pkgtools/pkglint/files/doc/pkglint.xml b/pkgtools/pkglint/files/doc/pkglint.xml
index f036b5d3503..f0a1a512668 100644
--- a/pkgtools/pkglint/files/doc/pkglint.xml
+++ b/pkgtools/pkglint/files/doc/pkglint.xml
@@ -11,9 +11,10 @@
 	<!ENTITY chap.types SYSTEM "chap.types.xml">
 	<!ENTITY chap.code SYSTEM "chap.code.xml">
 	<!ENTITY chap.statemachines SYSTEM "chap.statemachines.xml">
+	<!ENTITY chap.future SYSTEM "chap.future.xml">
 ]>
 
-<!-- $NetBSD: pkglint.xml,v 1.2 2006/02/28 11:40:15 rillig Exp $ -->
+<!-- $NetBSD: pkglint.xml,v 1.3 2006/05/23 08:10:37 rillig Exp $ -->
 
 <book>
 <title>Design and implementation of &pkglint;</title>
@@ -32,5 +33,6 @@
 &chap.types;
 &chap.code;
 &chap.statemachines;
+&chap.future;
 
 </book>
-- 
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