Amstrad DDI-1 manual Catch, Error, Pause, Throw

Models: DDI-1

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4.10.16EXCEPTION HANDLING:

catch

Traps errors and special conditions that occur during the execution of the input instruction list.

>catch "error[+[][]] >pr [I am here]

I am here

error

Outputs a list whose elements describe the most recent error.

>catch "error[do.until.error] >show error

pause

Suspends the execution of the current procedure to allow interaction with the interpreter or editor.

>if :size>5 [pause]

throw

Executes the line identified by the input name in a previous catch expression.

?throw "TOPLEVEL

4.10.17 SYSTEM PRIMITIVES

.contents Displays the contents of Dr. LOGO symbol space

.deposit Puts second input number into the absolute memory location specified by the first input number

.examine Displays the contents of the absolute memory location specified.

4.10.18SYSTEM VARIABLES ERRACT

When TRUE causes a pause when an error occurs, then returns to TOPLEVEL.

FALSE

System value

REDEFP

When TRUE allows redefinition of primitives.

Chapter 4.23

AMSTRAD Disc Drive & Interface DDI-1 Manual

Page 81
Image 81
Amstrad DDI-1 manual Catch, Error, Pause, Throw