iX Computer Systems - Edition 1 (32715-90001)

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Chapter 1 Introductions

HP Business BASIC/XL is a high level programming language implemented on

the 900 Series HP 3000. The BASIC language was developed to teach

beginners about computer programming. HP Business BASIC/XL takes

advantage of that ease of use, yet also provides a full interface to the

powerful MPE XL operating system.

HP Business BASIC/XL contains built-in interfaces to the IMAGE database

management system, VPLUS screen handler, and terminal softkeys. It also

features a report generator, sophisticated error handling capabilities,

and a static analyzer in the interpreter.

HP Business BASIC/XL has an interpreter and a compiler. Programs can be

developed with the interpreter, which has the features of an editor,

debugger, and calculator. Working programs can be compiled to increase

their speed and decrease their required storage space.

The interpreter checks the syntax of each line as it is entered, provides

immediate feedback about syntax errors and the effect of program

modifications, and allows quick transition between editing and running a

program.

HP Business BASIC/XL provides many statements and commands that

facilitate debugging. The interpreter's HELP command provides immediate

information about the syntax and function of any HP Business BASIC/XL

keyword or statement. Used as a calculator, the interpreter returns the

value of any expression. TRACE statements print messages when one line

transfers control to another line or when variables are assigned a val-

ue.The PAUSE statement suspends program execution, during which time

variable values and program lines can be displayed and modified. Pro-

gram execution can then be continued, and the effect of any changes can

be examined.