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Delta User’s Manual

about it in Chapter 6. We just wanted to illustrate a code that causes Delta to perform a function.

The escape

code

 

 

 

There’s

one particular

ASCII code that we are going to be

-

using more than all the rest. This is ASCII 27, which is called

 

escape. In BASIC it’s CHR$(27). With all of Delta’s advanced fea-

 

tures, there weren’t enough single ASCII codes to go around. So

 

escape is used to start sequences of control codes that open a

-

wider range of functions to us.

 

 

 

While you must call this code CHR$(27) in BASIC, we are

-

going to refer

to it as (ESC)

in this book. This will make

it much -

easier to recognize when we use it.

 

 

A typical

escape code

sequence starts with (ESC)

which is

-

followed by one or more CHR$ codes. As an example, the escape

 

code sequence

to turn on italic print is:

 

-

(ESC)

CHR$(52)

 

 

-

 

 

 

-

In a program, this would look like this:

-

NEW

18LPRINTCHR$(27)CHR$(52); 2$3LPRINT "TESTING"

RUN

-

-

Try this program, it will print the word TESTING in italic.

-

Some of you fast students may have noticed that CHR$(52) is

 

the same as “4”. That’s right, the program will work just as well if

 

line 10 is changed like this:

 

-

-

lpiLPRINTCHR$(27)"4";

That’s just another form of the same ASCII code, and it’s all the same to Delta.

Here’s another shortcut for BASIC programmers: since (ESC) is used so often, assign it to a variable. In a long program, typing ESC$ is much easier than typing CHR$(27) each time! Now

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Image 38
Star Micronics Delta user manual NEW LPRINTCHR$27CHR$52 2$3LPRINT Testing RUN, Escape Code