OpenCores
URL https://opencores.org/ocsvn/openrisc/openrisc/trunk

Subversion Repositories openrisc

[/] [openrisc/] [trunk/] [rtos/] [ecos-2.0/] [doc/] [html/] [cdl-guide/] [language.html] - Blame information for rev 174

Details | Compare with Previous | View Log

Line No. Rev Author Line
1 28 unneback 
<!-- Copyright (C) 2003 Red Hat, Inc.                                -->
2 
<!-- This material may be distributed only subject to the terms      -->
3 
<!-- and conditions set forth in the Open Publication License, v1.0  -->
4 
<!-- or later (the latest version is presently available at          -->
5 
<!-- http://www.opencontent.org/openpub/).                           -->
6 
<!-- Distribution of the work or derivative of the work in any       -->
7 
<!-- standard (paper) book form is prohibited unless prior           -->
8 
<!-- permission is obtained from the copyright holder.               -->
9 
<HTML
10 
><HEAD
11 
><TITLE
12 
>The CDL Language</TITLE
13 
><meta name="MSSmartTagsPreventParsing" content="TRUE">
14 
<META
15 
NAME="GENERATOR"
16 
CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+
17 
"><LINK
18 
REL="HOME"
19 
TITLE="The eCos Component Writer's Guide"
20 
HREF="cdl-guide.html"><LINK
21 
REL="PREVIOUS"
22 
TITLE="Making a Package Distribution"
23 
HREF="package.distrib.html"><LINK
24 
REL="NEXT"
25 
TITLE="CDL Commands"
26 
HREF="language.commands.html"></HEAD
27 
><BODY
28 
CLASS="CHAPTER"
29 
BGCOLOR="#FFFFFF"
30 
TEXT="#000000"
31 
LINK="#0000FF"
32 
VLINK="#840084"
33 
ALINK="#0000FF"
34 
><DIV
35 
CLASS="NAVHEADER"
36 
><TABLE
37 
SUMMARY="Header navigation table"
38 
WIDTH="100%"
39 
BORDER="0"
40 
CELLPADDING="0"
41 
CELLSPACING="0"
42 
><TR
43 
><TH
44 
COLSPAN="3"
45 
ALIGN="center"
46 
>The <SPAN
47 
CLASS="APPLICATION"
48 
>eCos</SPAN
49 
> Component Writer's Guide</TH
50 
></TR
51 
><TR
52 
><TD
53 
WIDTH="10%"
54 
ALIGN="left"
55 
VALIGN="bottom"
56 
><A
57 
HREF="package.distrib.html"
58 
ACCESSKEY="P"
59 
>Prev</A
60 
></TD
61 
><TD
62 
WIDTH="80%"
63 
ALIGN="center"
64 
VALIGN="bottom"
65 
></TD
66 
><TD
67 
WIDTH="10%"
68 
ALIGN="right"
69 
VALIGN="bottom"
70 
><A
71 
HREF="language.commands.html"
72 
ACCESSKEY="N"
73 
>Next</A
74 
></TD
75 
></TR
76 
></TABLE
77 
><HR
78 
ALIGN="LEFT"
79 
WIDTH="100%"></DIV
80 
><DIV
81 
CLASS="CHAPTER"
82 
><H1
83 
><A
84 
NAME="LANGUAGE">Chapter 3. The CDL Language</H1
85 
><DIV
86 
CLASS="TOC"
87 
><DL
88 
><DT
89 
><B
90 
>Table of Contents</B
91 
></DT
92 
><DT
93 
><A
94 
HREF="language.html#LANGUAGE.OVERVIEW"
95 
>Language Overview</A
96 
></DT
97 
><DT
98 
><A
99 
HREF="language.commands.html"
100 
>CDL Commands</A
101 
></DT
102 
><DT
103 
><A
104 
HREF="language.properties.html"
105 
>CDL Properties</A
106 
></DT
107 
><DT
108 
><A
109 
HREF="language.naming.html"
110 
>Option Naming Convention</A
111 
></DT
112 
><DT
113 
><A
114 
HREF="language.tcl.html"
115 
>An Introduction to Tcl</A
116 
></DT
117 
><DT
118 
><A
119 
HREF="language.values.html"
120 
>Values and Expressions</A
121 
></DT
122 
><DT
123 
><A
124 
HREF="language.interface.html"
125 
>Interfaces</A
126 
></DT
127 
><DT
128 
><A
129 
HREF="language.database.html"
130 
>Updating the <SPAN
131 
CLASS="DATABASE"
132 
>ecos.db</SPAN
133 
> database</A
134 
></DT
135 
></DL
136 
></DIV
137 
><P
138 
>The <SPAN
139 
CLASS="APPLICATION"
140 
>CDL</SPAN
141 
> language is a key part of the <SPAN
142 
CLASS="APPLICATION"
143 
>eCos</SPAN
144 
> component framework.
145 
All packages must come with at least one <SPAN
146 
CLASS="APPLICATION"
147 
>CDL</SPAN
148 
> script, to describe
149 
that package to the framework. The information in that script includes
150 
details of all the configuration options and how to build the package.
151 
Implementing a new component or turning some existing code into an
152 
<SPAN
153 
CLASS="APPLICATION"
154 
>eCos</SPAN
155 
> component always involves writing corresponding <SPAN
156 
CLASS="APPLICATION"
157 
>CDL</SPAN
158 
>. This
159 
chapter provides a description of the <SPAN
160 
CLASS="APPLICATION"
161 
>CDL</SPAN
162 
> language. Detailed
163 
information on specific parts of the language can be found in <A
164 
HREF="reference.html"
165 
>Chapter 5</A
166 
>.</P
167 
><DIV
168 
CLASS="SECT1"
169 
><H1
170 
CLASS="SECT1"
171 
><A
172 
NAME="LANGUAGE.OVERVIEW">Language Overview</H1
173 
><P
174 
>A very simple <SPAN
175 
CLASS="APPLICATION"
176 
>CDL</SPAN
177 
> script would look like this:</P
178 
><TABLE
179 
BORDER="5"
180 
BGCOLOR="#E0E0F0"
181 
WIDTH="70%"
182 
><TR
183 
><TD
184 
><PRE
185 
CLASS="PROGRAMLISTING"
186 
>cdl_package CYGPKG_ERROR {
187 
    display       "Common error code support"
188 
    compile       strerror.cxx
189 
    include_dir   cyg/error
190 
    description   "
191 
        This package contains the common list of error and
192 
        status codes. It is held centrally to allow
193 
        packages to interchange error codes and status
194 
        codes in a common way, rather than each package
195 
        having its own conventions for error/status
196 
        reporting. The error codes are modelled on the
197 
        POSIX style naming e.g. EINVAL etc. This package
198 
        also provides the standard strerror() function to
199 
        convert error codes to textual representation."
200 
}</PRE
201 
></TD
202 
></TR
203 
></TABLE
204 
><P
205 
>This describes a single package, the error code package, which does
206 
not have any sub-components or configuration options. The package has
207 
an internal name, <TT
208 
CLASS="VARNAME"
209 
>CYGPKG_ERROR</TT
210 
>, which can be
211 
referenced in other <SPAN
212 
CLASS="APPLICATION"
213 
>CDL</SPAN
214 
> scripts using e.g.
215 
<TT
216 
CLASS="LITERAL"
217 
>requires&nbsp;CYGPKG_ERROR</TT
218 
>. There will also be a
219 
<TT
220 
CLASS="LITERAL"
221 
>#define</TT
222 
> for this symbol in a configuration header
223 
file. In addition to the package name, this script provides a number
224 
of properties for the package as a whole. The <SPAN
225 
CLASS="PROPERTY"
226 
>display</SPAN
227 
> property
228 
provides a short description. The <SPAN
229 
CLASS="PROPERTY"
230 
>description</SPAN
231 
> property involves a
232 
rather longer one, for when users need a bit more information. The
233 
<SPAN
234 
CLASS="PROPERTY"
235 
>compile</SPAN
236 
> and <SPAN
237 
CLASS="PROPERTY"
238 
>include_dir</SPAN
239 
> properties list the consequences of this
240 
package at build-time. The package appears to lack any on-line
241 
documentation. </P
242 
><P
243 
>Packages could be even simpler than this. If the package only provides
244 
an interface and there are no files to be compiled then there is no
245 
need for a <SPAN
246 
CLASS="PROPERTY"
247 
>compile</SPAN
248 
> property. Alternatively if there are no exported
249 
header files, or if the exported header files should go to the
250 
top-level of the <TT
251 
CLASS="FILENAME"
252 
>install/include</TT
253 
> directory, then there is
254 
no need for an <SPAN
255 
CLASS="PROPERTY"
256 
>include_dir</SPAN
257 
> property. Strictly speaking the
258 
<SPAN
259 
CLASS="PROPERTY"
260 
>description</SPAN
261 
> and <SPAN
262 
CLASS="PROPERTY"
263 
>display</SPAN
264 
> properties are optional as well, although
265 
application developers would not appreciate the resulting lack of
266 
information about what the package is supposed to do.</P
267 
><P
268 
>However many packages tend to be a bit more complicated than the error
269 
package, containing various sub-components and configuration options.
270 
These are also defined in the <SPAN
271 
CLASS="APPLICATION"
272 
>CDL</SPAN
273 
> scripts and in much the same way
274 
as the package. For example, the following excerpt comes from the
275 
infrastructure package:</P
276 
><TABLE
277 
BORDER="5"
278 
BGCOLOR="#E0E0F0"
279 
WIDTH="70%"
280 
><TR
281 
><TD
282 
><PRE
283 
CLASS="PROGRAMLISTING"
284 
>cdl_component CYGDBG_INFRA_DEBUG_TRACE_ASSERT_BUFFER {
285 
    display       "Buffered tracing"
286 
    default_value 1
287 
    active_if     CYGDBG_USE_TRACING
288 
    description   "
289 
        An output module which buffers output from tracing and
290 
        assertion events. The stored messages are output when an
291 
        assert fires, or CYG_TRACE_PRINT() (defined in
292 
        &lt;cyg/infra/cyg_trac.h&gt;) is called. Of course, there will
293 
        only be stored messages if tracing per se (CYGDBG_USE_TRACING)
294 
        is enabled above."
295 
 
296 
    cdl_option CYGDBG_INFRA_DEBUG_TRACE_BUFFER_SIZE {
297 
        display       "Trace buffer size"
298 
        flavor        data
299 
        default_value 32
300 
        legal_values  5 to 65535
301 
        description   "
302 
            The size of the trace buffer. This counts the number of
303 
            trace records stored. When the buffer fills it either
304 
            wraps, stops recording, or generates output."
305 
    }
306 
 
307 
    &#8230;
308 
}</PRE
309 
></TD
310 
></TR
311 
></TABLE
312 
><P
313 
>Like a <TT
314 
CLASS="LITERAL"
315 
>cdl_package</TT
316 
>, a <TT
317 
CLASS="LITERAL"
318 
>cdl_component</TT
319 
> has a name and a body. The
320 
body contains various properties for that component, and may also
321 
contain sub-components or options. Similarly a <TT
322 
CLASS="LITERAL"
323 
>cdl_option</TT
324 
> has a
325 
name and a body of properties. This example lists a number of
326 
new properties: <SPAN
327 
CLASS="PROPERTY"
328 
>default_value</SPAN
329 
>, <SPAN
330 
CLASS="PROPERTY"
331 
>active_if</SPAN
332 
>, <SPAN
333 
CLASS="PROPERTY"
334 
>flavor</SPAN
335 
> and
336 
<SPAN
337 
CLASS="PROPERTY"
338 
>legal_values</SPAN
339 
>. The meaning of most of these should be fairly obvious.
340 
The next sections describe the various <SPAN
341 
CLASS="APPLICATION"
342 
>CDL</SPAN
343 
> commands and properties. </P
344 
><P
345 
>There is one additional and very important point: <SPAN
346 
CLASS="APPLICATION"
347 
>CDL</SPAN
348 
> is not a
349 
completely new language; instead it is implemented as an extension of
350 
the existing <SPAN
351 
CLASS="APPLICATION"
352 
>Tcl</SPAN
353 
> scripting language. The syntax of a <SPAN
354 
CLASS="APPLICATION"
355 
>CDL</SPAN
356 
> script is
357 
<SPAN
358 
CLASS="APPLICATION"
359 
>Tcl</SPAN
360 
> syntax, which is described below. In addition some of the more
361 
advanced facilities of <SPAN
362 
CLASS="APPLICATION"
363 
>CDL</SPAN
364 
> involve embedded fragments of <SPAN
365 
CLASS="APPLICATION"
366 
>Tcl</SPAN
367 
> code,
368 
for example there is a <SPAN
369 
CLASS="PROPERTY"
370 
>define_proc</SPAN
371 
> property which specifies some
372 
code that needs to be executed when the component framework generates
373 
the configuration header files.</P
374 
></DIV
375 
></DIV
376 
><DIV
377 
CLASS="NAVFOOTER"
378 
><HR
379 
ALIGN="LEFT"
380 
WIDTH="100%"><TABLE
381 
SUMMARY="Footer navigation table"
382 
WIDTH="100%"
383 
BORDER="0"
384 
CELLPADDING="0"
385 
CELLSPACING="0"
386 
><TR
387 
><TD
388 
WIDTH="33%"
389 
ALIGN="left"
390 
VALIGN="top"
391 
><A
392 
HREF="package.distrib.html"
393 
ACCESSKEY="P"
394 
>Prev</A
395 
></TD
396 
><TD
397 
WIDTH="34%"
398 
ALIGN="center"
399 
VALIGN="top"
400 
><A
401 
HREF="cdl-guide.html"
402 
ACCESSKEY="H"
403 
>Home</A
404 
></TD
405 
><TD
406 
WIDTH="33%"
407 
ALIGN="right"
408 
VALIGN="top"
409 
><A
410 
HREF="language.commands.html"
411 
ACCESSKEY="N"
412 
>Next</A
413 
></TD
414 
></TR
415 
><TR
416 
><TD
417 
WIDTH="33%"
418 
ALIGN="left"
419 
VALIGN="top"
420 
>Making a Package Distribution</TD
421 
><TD
422 
WIDTH="34%"
423 
ALIGN="center"
424 
VALIGN="top"
425 
>&nbsp;</TD
426 
><TD
427 
WIDTH="33%"
428 
ALIGN="right"
429 
VALIGN="top"
430 
>CDL Commands</TD
431 
></TR
432 
></TABLE
433 
></DIV
434 
></BODY
435 
></HTML
436 
>

powered by: WebSVN 2.1.0

© copyright 1999-2024 OpenCores.org, equivalent to Oliscience, all rights reserved. OpenCores®, registered trademark.