TOPS-20 PASCAL Language Manual - Bitsavers

INPUT AND OUTPUT
For a variable of an enumerated type, PASCAL prints the constant
identifier denoting the variable's value. Because PASCAL ignores any
characters beyond the thirty-first in an identifier, only the first 31
characters of a long identifier appear, for example:
VAR Color :
BEGIN
WRITE ('M~ favorite color is ',Color:35);
(Blue,Yellow,Black,Sli~htl~_Pale_Peach_Summer_Sun5et)~
END;
When the value of Color is Yellow, the following is printed:
M~ favorite color is YELLOW
When the value of Color is Slightly_Pale Peach Summer_Sunset, however,
the following appears:
My favorite color is
Although the field width specified is wide enough for all 33
characters in the identifier, PASCAL ignores the last two characters
and prints two leading blanks. Note that constants of enumerated
types are printed in all uppercase characters.
If you open the predeclared file OUTPUT with the carriage control
option LIST, PASCAL allows you to use the WRITE procedure to prompt
for input at the terminal. Each time you read from INPUT, the system
checks for any output in the terminal record buffer. If the buffer
contains any characters, the system prints them at the terminal, but
suppresses the carriage return at the end of the lin(~. The output
text appears as a prompt, and you can type your input on the same
line, for example:
WRITE ('Name three presidents:');
READ (Pres1, Pres2, Pres3);
When PASCAL executes the READ procedure, it finds the output string
waiting to be printed. PASCAL prints the prompt at the terminal,
leaving the carriage just after the colon (:). You can then begin
typing input on the same line as the prompt.
Prompting works only for the predeclared files INPUT and OUTPUT. For
any other files, no output is written until you fill the record buffer
or start a new line.
Example 1
TYPE Strins = PACKED ARRAY [1 •• 20] OF CHAR;
VAR Names: FILE OF Strins;
Pres String;
BEGIN
WRITE (Names, 'Millard Fillmore " Pres);
END;
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