A Computer Person Journey
lsort is a command to return a sorted list based on option. Default option is to sort alphabetically (-ascii) and ascending (-increasing). lsort can also sort numerically using -integer or -real option. lsort can also sort based on a element on sub list using -index option.
There are more options available. Here we will see some examples of lsort in action.
Octalogue is eight rules that describe Tcl language as found from https://wiki.tcl-lang.org/page/Dodekalogue.
All in tcl is string, so expr exist as command to evaluate numeric value. On other language like ruby if we write 1+2 <enter> on the irb console will print 3, but thats not the case with tcl.
To get numeric calculation on Tcl we need to use expr command.
Evaluating logical also work with expr command. Examples below.
By remembering Tcl rule : “All is string”, we can conclude that expr result will be string as well.
To add new element to tcl list there are 2 command linsert and lappend.
Lappend is command to append new elements to the end of variable containing list.
Linsert is command to return new list with new elements inserted before index of passed to the command.
Some examples : Continue reading “Tcl list operation : lappend & linsert”
Here i try to use fossil to create a new repository file named bprs.fossil that will contain files from a java project. After doing fossil init to create the repository file then im opening the repo on a directory named bprs_checkout. Continue reading “Creating fossil repository and commit some files”
Recently bitbucket accounce that they will discontinue mercurial support on their hosting by 2020. This event make me move my existing mercurial repo on bitbucket to git which they also support.
Recently i also learning some about Tcl and come across that Tcl project use fossil as their version control. But fossil is more than version control ! Its also unique by using sqlite database as its repository storage. No wonder because fossil is created to support sqlite project by its creator D Richard Hipp.
So i came to study fossil SCM on its website and installing it on my linux, openbsd, and windows laptop. Installing on openbsd is done by pkg_add fossil. Fossil website also provide fossil as a precompiled binary file and all you do to install is by copying it to your path. Its simple and powerful.
Go to fossil website :
https://www.fossil-scm.org/home
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.