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TBASIC.7
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1984-04-29
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* DROP <numeric expression>,<numeric expression>
Drops the assignment of the logical device selected by the first
expression to the physical device selected by the second expression.
Examples: DROP 1,1 DROP LOGICAL,PHYSICAL DROP PRINTD,TTY
END
Puts BASIC back in command mode. Normally the last statement in
a program. Not required. Example: END
FOR <variable name> = <expr1> TO <expr2> [STEP <expr3>]
Execution sets <variable name> = <expr1>. The program then proceeds
until a "NEXT" statement is encountered. <expr3> (or 1 if STEP <expr3>
is omitted) is then added to <variable name>. If <expr3> < 0 and
<variable name> >= <expr2>, or if <expr3> >0 and <variable name> <= <expr3>,
then the program continues with the statement following the "FOR" statement.
Otherwise, the program continues after the "NEXT" statement.
Example: FOR N=1 TO 5 Example: FOR IND=START TO FINISH STEP INCR
* GOPROC <line descriptor>[,<variable list>]
Calls the statement <line descriptor>, passing the variables on the
list. Similar to GOSUB, except it allows the subroutine to have
local variables, which are not affected by assignments outside
the procedure. Also allows passing variables to the subroutine.
The subroutine need not contain a PROCEDURE statement.
Example: GOPROC SEARCH,STR1$,STR2$,POSITION
GOSUB <line descriptor>
A subroutine call is made to the line indicated. That is,
execution continues at <line descriptor> until a RETURN statement
is encountered, at which time execution is continued at the
statement following the GOSUB statement.
Examples: GOSUB CALC GOSUB 10570 GOSUB GET+1
GOTO <line descriptor>
An unconditional branch is made to the line indicated. That is,
execution continues at <line descriptor> instead of the next
statement. Examples: GOTO 100 GOTO LOOP+2 GOTO LAST-5
* IF <logical expression> GOTO <line descriptor>
If the value of <logical expression> = -1, then execution
continues at the line indicated. Otherwise, execution continues
with the line following the IF statement. The logical connectives
allowed in <logical expression> are: AND, OR, NOT, >, <, = .
See Appendix B for explanation of logical expressions.
Examples: IF X<128 AND X>31 GOTO EXTRA IF STR$<>"NO" GOTO 100
* IF <logical expression> THEN <statement> [ELSE <statement>]
If the value of <logical expression> = -1 (true), then the first
<statement> is executed. Otherwise, it is not. If the ELSE option is
used, the second statement is executed if the value of <logical
expression> is false. See Appendix B for def. of logical expression.
Examples: IF ANS$="YES" THEN GOSUB INSTR IF 3*Y=4 THEN PRINT "OK"
IF ARRAY(N)=0 THEN GOTO LOOP ELSE STOP
INPUT <variable list>
Assigns entries from the console device to the variables on the list.
Prompts may be included by enclosing a string expression in quotes,
separated from the variables by semicolons. Prompts are printed in
the order they appear on the list. With no prompt, a "?" is printed.
A carriage return must be used to terminate string input.
Examples: INPUT A,B$ INPUT "FILENAME";NAM$
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