variable

variable

NAME
SYNOPSIS
DESCRIPTION
EXAMPLES
SEE ALSO
KEYWORDS

---

___________________________

NAME

variable − create and initialize a namespace variable

SYNOPSIS

variable name

variable ?name value...? ___________________________

DESCRIPTION

This command is normally used within a namespace eval command to create one or more variables within a namespace. Each variable name is initialized with value. The value for the last variable is optional.

If a variable name does not exist, it is created. In this case, if value is specified, it is assigned to the newly created variable. If no value is specified, the new variable is left undefined. If the variable already exists, it is set to value if value is specified or left unchanged if no value is given. Normally, name is unqualified (does not include the names of any containing namespaces), and the variable is created in the current namespace. If name includes any namespace qualifiers, the variable is created in the specified namespace. If the variable is not defined, it will be visible to the namespace which command, but not to the info exists command.

If the variable command is executed inside a Tcl procedure, it creates local variables linked to the corresponding namespace variables (and therefore these variables are listed by info vars.) In this way the variable command resembles the global command, although the global command only links to variables in the global namespace. If any values are given, they are used to modify the values of the associated namespace variables. If a namespace variable does not exist, it is created and optionally initialized.

A name argument cannot reference an element within an array. Instead, name should reference the entire array, and the initialization value should be left off. After the variable has been declared, elements within the array can be set using ordinary set or array commands.

EXAMPLES

Create a variable in a namespace:

namespace eval foo {
variable bar 12345
}

Create an array in a namespace:

namespace eval someNS {
variable someAry
array set someAry {
someName someValue
otherName otherValue
}
}

Access variables in namespaces from a procedure:

namespace eval foo {
proc spong {} {
# Variable in this namespace
variable bar
puts "bar is $bar"

# Variable in another namespace
variable ::someNS::someAry
parray someAry
}
}

SEE ALSO

global(n), namespace.conf(5), upvar(n)

KEYWORDS

global, namespace, procedure, variable

---

---

---

Opportunity

Personal Opportunity - Free software gives you access to billions of dollars of software at no cost. Use this software for your business, personal use or to develop a profitable skill. Access to source code provides access to a level of capabilities/information that companies protect though copyrights. Open source is a core component of the Internet and it is available to you. Leverage the billions of dollars in resources and capabilities to build a career, establish a business or change the world. The potential is endless for those who understand the opportunity.

Business Opportunity - Goldman Sachs, IBM and countless large corporations are leveraging open source to reduce costs, develop products and increase their bottom lines. Learn what these companies know about open source and how open source can give you the advantage.

---

---

Free Software

Free Software provides computer programs and capabilities at no cost but more importantly, it provides the freedom to run, edit, contribute to, and share the software. The importance of free software is a matter of access, not price. Software at no cost is a benefit but ownership rights to the software and source code is far more significant.

---

Free Office Software - The Libre Office suite provides top desktop productivity tools for free. This includes, a word processor, spreadsheet, presentation engine, drawing and flowcharting, database and math applications. Libre Office is available for Linux or Windows.

---

---

Free Books

The Free Books Library is a collection of thousands of the most popular public domain books in an online readable format. The collection includes great classical literature and more recent works where the U.S. copyright has expired. These books are yours to read and use without restrictions.

---

Source Code - Want to change a program or know how it works? Open Source provides the source code for its programs so that anyone can use, modify or learn how to write those programs themselves. Visit the GNU source code repositories to download the source.

---

---

Education

Study at Harvard, Stanford or MIT - Open edX provides free online courses from Harvard, MIT, Columbia, UC Berkeley and other top Universities. Hundreds of courses for almost all major subjects and course levels. Open edx also offers some paid courses and selected certifications.

---

Linux Manual Pages - A man or manual page is a form of software documentation found on Linux/Unix operating systems. Topics covered include computer programs (including library and system calls), formal standards and conventions, and even abstract concepts.

---