Lexical Elements of the DEC Text Processing Utility Language 4.4 Identifiers

4.4 Identifiers

In DECTPU, identifiers are used to name programs, procedures, keywords, and variables. An identifier is a combination of alphabetic characters, digits, dollar signs, and underscores, and it must conform to the following restrictions:

•An identifier cannot contain any spaces or symbols except the dollar sign and the underscore.

•Identifiers cannot be more than 132 characters long.

DECTPU identifiers for built-in procedures, constants, keywords, and global variables are reserved words.

You can create your own identifiers to name programs, procedures, constants, and variables. Any symbol that is neither declared nor used as the target of an assignment statement is assumed to be an undefined procedure.

4.5 Variables

Variables are names given to DECTPU storage locations that hold values. A variable name can be any valid DECTPU identifier that is not a DECTPU reserved word or the name of a DECTPU procedure. You assign a value to a variable by using a valid identifier as the left-hand side of an assignment statement. Following is an example of a variable assignment:

new_buffer := CREATE_BUFFER ("new_buffer_name");

Compaq suggests that you establish some convention for naming variables so that you can distinguish your variables from the variables in the section file that you are using.

DECTPU allows two kinds of variables: global and local. Global variables are in effect throughout a DECTPU environment. Local variables are evaluated only within the procedure or unbound code in which they are declared. A variable is implicitly global unless you use the LOCAL declaration. You can also declare global variables with the VARIABLE declaration.

Example 4–1 shows a global variable declaration and a procedure that contains a local variable declaration.

Example 4–1 Global and Local Variable Declarations

VARIABLE user_tab_char;

!Tab key procedure. Always inserts a tab, even if current mode

!is overstrike.

PROCEDURE user_tab

LOCAL this_mode; ! Local variable for current mode

this_mode := GET_INFO (CURRENT_BUFFER, "mode"); ! Save current mode

SET (INSERT, CURRENT_BUFFER);

! Set mode to insert

user_tab_char := ASCII (9);

! Define the tab char

COPY_TEXT (user_tab_char);

! Insert tab

SET (this_mode, CURRENT_BUFFER);

! Reset original mode

ENDPROCEDURE;

 

Lexical Elements of the DEC Text Processing Utility Language 4–5

Page 70 Page 72
Page 71
Image 71
Compaq AA-PWCBD-TE manual Identifiers, Variables, Example 4-1 Global and Local Variable Declarations
Page 70 Page 72

AA-PWCBD-TE specifications

The Compaq AA-PWCBD-TE is a highly regarded laptop battery designed to provide reliable power to a range of Compaq laptop models. As technology continues to evolve, the necessity for efficient and long-lasting batteries becomes increasingly important, especially for students, professionals, and anyone reliant on portable computing.

One of the standout features of the AA-PWCBD-TE is its impressive capacity, designed to enhance the performance of your device. With a power capacity of around 5200 mAh, this battery is engineered to provide extended usage times, allowing users to work on the go without frequent interruptions for recharging. The battery supports efficient energy management, contributing to the overall longevity of the device.

Additionally, the AA-PWCBD-TE integrates advanced lithium-ion technology, which is favored for its reliability and minimal memory effect. Lithium-ion batteries typically offer a higher energy density compared to older technologies, meaning they can store more energy in a smaller size. This technology also supports faster charging times, making it a convenient solution for busy users.

Safety is another vital characteristic of the AA-PWCBD-TE. It features built-in protection against overcharging, overheating, and short-circuit conditions, which helps ensure the safety of both the battery and the device itself. This level of protection is crucial, especially in professional environments where equipment failure can lead to productivity losses.

Compatibility is also a key aspect of the AA-PWCBD-TE, as it is designed to fit a variety of Compaq laptop models. Users can easily determine whether this battery is suitable for their specific model, simplifying the buying process and ensuring optimal performance.

In terms of weight and dimensions, the AA-PWCBD-TE is designed to be lightweight and compact, adding minimal bulk to the laptop while still delivering powerful performance. Users can enjoy the balance of efficiency and portability, making it an ideal choice for those who travel frequently or require a battery that doesn't compromise on power.

Overall, the Compaq AA-PWCBD-TE stands out as a dependable and efficient laptop battery that enhances the user experience. With its impressive capacity, cutting-edge technology, and safety features, it is a valuable accessory for anyone looking to improve their mobile computing capabilities.
Top Page Image Contents