Category: tcl

OpenOCD website have good resource for learning Tcl. They used Jim Tcl internally for the project.

http://openocd.org/doc/html/Tcl-Crash-Course.html

Here is Tcl rules according to the course. Continue reading “Tcl Crash Course”

Tcl have lset command to change value of list’s element.

lset varname index newvalue

Some example of lset on variable named a is presented below.

Lset command can set value of nested list too.

Thats all …

Here is various way to create nested list in tcl. Remember that every thing is a string in Tcl.

% set nestedlist1 { 1 2 { a b c } 3 { d e f } 4 5 }

%set nestedlist2 [list 1 2 [list a b c] 3 [list d e f] 4 5]

%set innerlist1 {a b c}

%set innerlist2 [list d e f]

%set nestedlist3 “1 2 $innerlist1 3 $innerlist2 4 5”

Lindex command can also used to extract an element of nested list.

%lindex $nestedlist1 2 1

b

Try it on tclsh by hand ! Bye …

In Tcl everything is a string. List is also a string. The simplest form of list is a string with zero or more space separated words. Lets set a variable with 3 elements list containing 1,2, and 3.

% set var1 “1 2 3”

% set var2 [list 1 2 3]

% set var3 {1 2 3}

Here we set var1,var2, and var3 to a list, with 3 different way.

To return the number of elements in a list we can use llength command.

% llength $var1

3

To extract an element from list we can use lindex command.

% lindex $var1   1

2

As we can see list has zero based index. The first element is at index 0. Lindex command can accept end and end-? as argument.

% lindex $var1   end

3

% lindex $var1  end-1

2

Thats all for now.

Do you need a Tcl tutorial ? Salvatore write one that we can read online here :

http://www.invece.org/tclwise/

Also check out a n interesting Tcl language implementation here :

http://jim.tcl.tk