Manual copied from ANSTO branch and committed to RELEASE-3_0 branch.
This directory was accidentally omitted from the merge-release branch during the PSI code merge.
This commit is contained in:
Nick Hauser
209
site_ansto/manual/dbSICSch10_tcl_commands.xml
Normal file
209
site_ansto/manual/dbSICSch10_tcl_commands.xml
Normal file
@@ -0,0 +1,209 @@
|
||||
<?xml version="1.0" encoding="UTF-8"?>
|
||||
<?oxygen RNGSchema="http://www.oasis-open.org/docbook/xml/5.0/rng/docbook.rng" type="xml"?>
|
||||
<chapter xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink"
|
||||
version="5.0">
|
||||
<info><title>TCL command language interface</title><author><personname>Ferdi
|
||||
Franceschini</personname></author>
|
||||
<date>2006-08-17 14:01</date></info>
|
||||
<sect1>
|
||||
<title>Common commands & exclusions</title>
|
||||
<para>From the PSI SANS documentation by Dr. Joachim Kohlbrecher and Dr. Mark Könnecke with
|
||||
slight modifications.</para>
|
||||
<para>The macro language implemented in the SICS server is <uri
|
||||
xlink:href="http://home.pacbell.net/ouster/">John Ousterhout</uri> Tool Command
|
||||
Language <uri xlink:href="http://www.tcl.tk/">TCL</uri> . Tcl has control constructs,
|
||||
variables of its own, loop constructs, associative arrays and procedures. Tcl is well
|
||||
<uri xlink:href="http://www.tcl.tk/doc/">documented</uri> by several books, online
|
||||
tutorials and manuals. All SICS commands are available in the macro language. </para>
|
||||
<para>Some potentially harmful Tcl commands have been deleted from the standard Tcl
|
||||
interpreter. These are: </para>
|
||||
<para>
|
||||
<command>exec</command></para>
|
||||
<para><command>source</command></para>
|
||||
<para><command>puts</command></para>
|
||||
<para><command>vwait</command></para>
|
||||
<para><command>exit</command></para>
|
||||
<para><command>gets</command></para>
|
||||
<para><command>socket</command></para>
|
||||
<para>Below only a small subset of the most important Tcl commands like assigning variables,
|
||||
evaluating expressions, control and loop constructs are described. For complete
|
||||
description of Tcl commands have a look on the <uri
|
||||
xlink:href="http://www.tcl.tk/man/tcl8.4/">manual pages</uri> or on one of the many
|
||||
books about Tcl/Tk.</para>
|
||||
<variablelist>
|
||||
<varlistentry>
|
||||
<term><command>set </command><replaceable> varName value</replaceable>
|
||||
<command>set </command><replaceable>arrName(index) value</replaceable></term>
|
||||
<listitem>
|
||||
<para>Set/get scalar variables or array elements. Arrays in Tcl are actually
|
||||
associative arrays, this means that their indices are not restricted to
|
||||
integers. The following examples demonstrate setting a scalar variable and
|
||||
a couple of array elements. Note the third array example which shows that
|
||||
the same array can have mixed indices (the number 1 and 'one') as well as
|
||||
mixed data types (the number 10 and 'ten') in the same array.</para>
|
||||
<programlisting>set a 3
|
||||
set arr(1) 10
|
||||
set arr(one) ten</programlisting>
|
||||
</listitem>
|
||||
</varlistentry>
|
||||
<varlistentry>
|
||||
<term><command>expr </command><replaceable>arg arg arg</replaceable></term>
|
||||
<listitem>
|
||||
<para>Concatenates arg’s (adding separator spaces between them), evaluates the
|
||||
result as a Tcl expression, and returns the value. The operators permitted
|
||||
in Tcl expressions are a subset of the operators permitted in C expressions,
|
||||
and they have the same meaning and precedence as the corresponding C
|
||||
operators. Expressions almost always yield numeric results (integer or
|
||||
floating-point values). For example, the expression </para>
|
||||
<programlisting>expr 8.2 + 6</programlisting>
|
||||
<para>evaluates to 14.2. For some examples of simple expressions, suppose the
|
||||
variable a = 3 and b = 6. Then the commands shown below will produce the
|
||||
value after the ->
|
||||
</para>
|
||||
<programlisting>set a 3
|
||||
set b 6
|
||||
expr 3.1 + $a -> 6.1
|
||||
expr 2 + "$a.$b" -> 5.6
|
||||
expr [ splitreply [omega] ] / 2.0 ->
|
||||
omega axis position / 2.0</programlisting>
|
||||
<para>Note the use of square brackets [] for command substitution.</para>
|
||||
</listitem>
|
||||
</varlistentry>
|
||||
</variablelist>
|
||||
</sect1>
|
||||
<sect1>
|
||||
<title>Math functions</title>
|
||||
<para>Tcl supports the following mathematical functions in
|
||||
expressions:<?db2html element="br"?></para>
|
||||
<para><informaltable>
|
||||
<tgroup cols="4">
|
||||
<tbody>
|
||||
<row>
|
||||
<entry>acos</entry>
|
||||
<entry>cos </entry>
|
||||
<entry>hypot </entry>
|
||||
<entry>sinh </entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry>asin </entry>
|
||||
<entry>cosh </entry>
|
||||
<entry>log </entry>
|
||||
<entry>sqrt </entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry>atan </entry>
|
||||
<entry>exp </entry>
|
||||
<entry>log10 </entry>
|
||||
<entry>tan </entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry>atan2 </entry>
|
||||
<entry>floor </entry>
|
||||
<entry>pow </entry>
|
||||
<entry>tanh </entry>
|
||||
</row>
|
||||
<row>
|
||||
<entry>ceil </entry>
|
||||
<entry>fmod </entry>
|
||||
<entry>sin </entry>
|
||||
<entry> </entry>
|
||||
</row>
|
||||
</tbody>
|
||||
</tgroup>
|
||||
</informaltable>Note you must use the <command>expr</command> command to invoke these
|
||||
functions eg,</para>
|
||||
<programlisting>expr cos(0)
|
||||
set pi [expr acos(-1)]
|
||||
expr sin($pi)</programlisting>
|
||||
<para>Each of these functions invokes the math library function of the same name; see the
|
||||
manual entries for the library functions for details on what they do. Tcl also
|
||||
implements the following functions for conversion between integers and floating-point
|
||||
numbers and the generation of random numbers: </para>
|
||||
<para><command>abs</command>(<replaceable>arg</replaceable>),
|
||||
<command>double</command>(<replaceable>arg</replaceable>) ,
|
||||
<command>int</command>(<replaceable>arg</replaceable>),
|
||||
<command>rand</command>(<replaceable>arg</replaceable>),
|
||||
<command>round</command>(<replaceable>arg</replaceable>),
|
||||
<command>srand</command>(<replaceable>arg</replaceable>). </para>
|
||||
</sect1>
|
||||
<sect1>
|
||||
<title>if - execute scripts conditionally</title>
|
||||
<programlisting><command>if</command> <replaceable>expr1 </replaceable><command>then </command>
|
||||
<replaceable>body1</replaceable>
|
||||
<command>elseif </command><replaceable>expr2 </replaceable><command>then</command>
|
||||
<replaceable>body2</replaceable>
|
||||
<command>elseif</command>...
|
||||
<command>else</command>
|
||||
<replaceable>bodyN</replaceable>
|
||||
</programlisting>
|
||||
<para>The <command>if</command> command evaluates <replaceable>expr1</replaceable> as an
|
||||
expression (in the same way that <command>expr</command> evaluates its argument). The
|
||||
value of the expression must be a boolean (a numeric value, where 0 is false and
|
||||
anything is true, or a string value such as "true" or "yes" for true and "false" or "no"
|
||||
for false); if it is true then <replaceable>body1</replaceable> is executed by passing
|
||||
it to the Tcl interpreter. Otherwise <replaceable>expr2</replaceable> is evaluated as an
|
||||
expression and if it is true then <replaceable>body2</replaceable> is executed, and so
|
||||
on. If none of the expressions evaluates to true then <replaceable>bodyN</replaceable>
|
||||
is executed. The <command>then</command> and <command>else</command> arguments are
|
||||
optional "noise words" to make the command easier to read. There may be any number of
|
||||
<command>elseif</command> clauses, including zero. <replaceable>BodyN</replaceable>
|
||||
may also be omitted as long as <command>else</command> is omitted too. The return value
|
||||
from the command is the result of the body script that was executed, or an empty string
|
||||
if none of the expressions was non-zero and there was no
|
||||
<replaceable>bodyN</replaceable>. </para>
|
||||
<example>
|
||||
<title>"if"</title>
|
||||
<programlisting>set a 3
|
||||
if {$a == 3} {puts "a equals three"} </programlisting>
|
||||
</example>
|
||||
</sect1>
|
||||
<sect1>
|
||||
<title>for - "for" loop</title>
|
||||
<programlisting><command>for </command><replaceable>start test
|
||||
next
|
||||
body</replaceable>
|
||||
</programlisting>
|
||||
<para><command>for</command> is a looping command, similar in structure to the C
|
||||
<command>for</command> statement. The <replaceable>start, next</replaceable>, and
|
||||
<replaceable>body</replaceable> arguments must be Tcl command strings, and
|
||||
<replaceable>test</replaceable> is an expression string. If a
|
||||
<command>continue</command> command is invoked within <replaceable>body</replaceable>
|
||||
then any remaining commands in the current execution of <replaceable>body</replaceable>
|
||||
are skipped; processing continues by invoking the Tcl interpreter on
|
||||
<replaceable>next</replaceable>, then evaluating <replaceable>test</replaceable> , and
|
||||
so on. If a <command>break</command> command is invoked within
|
||||
<replaceable>body</replaceable> or <replaceable>next</replaceable> , then the
|
||||
<command>for</command> command will return immediately. The operation of
|
||||
<command>break</command> and <command>continue</command> are similar to the
|
||||
corresponding statements in C. <command>for</command> returns an empty string. </para>
|
||||
<example>
|
||||
<title>"for"</title>
|
||||
<programlisting>for {set x 0} {$x<10} {incr x} {puts "x is $x"}</programlisting>
|
||||
</example>
|
||||
</sect1>
|
||||
<sect1>
|
||||
<title>while - execute script repeatedly as long as a condition is met</title>
|
||||
<programlisting><command>while</command> <replaceable>test
|
||||
body </replaceable></programlisting>
|
||||
<para> The <command>while</command> command evaluates <replaceable>test</replaceable> as an
|
||||
expression (in the same way that <command>expr</command> evaluates its argument). The
|
||||
value of the expression must be a proper boolean value; if it is a true value then
|
||||
<replaceable>body</replaceable> is executed by passing it to the Tcl interpreter.
|
||||
Once <replaceable>body</replaceable> has been executed then
|
||||
<replaceable>test</replaceable> is evaluated again, and the process repeats until
|
||||
eventually <replaceable>test</replaceable> evaluates to a false boolean value.
|
||||
<command>continue</command> commands may be executed inside
|
||||
<replaceable>body</replaceable> to terminate the current iteration of the loop, and
|
||||
<command>break</command> commands may be executed inside <command>body</command> to
|
||||
cause immediate termination of the <command>while</command> command. The
|
||||
<command>while</command> command always returns an empty string. </para>
|
||||
<example>
|
||||
<title>"while"</title>
|
||||
<programlisting>set x 0
|
||||
while {$x<10} {
|
||||
puts "x is $x"
|
||||
incr x
|
||||
}</programlisting>
|
||||
</example>
|
||||
</sect1>
|
||||
</chapter>
|
||||
Reference in New Issue
Block a user