Catch, Error, Pause, Throw | Amstrad DDI-1 instruction

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

Image 81

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

Contents

Page Amstrad Disc Drive & Interface DDI-1 Amstrad Contents Contents Page Connecting the Mains Lead Foundations 1 Setting Up Connecting the DDI-1 to the Computer Computer Interface Unit Main Disc Drive Drive a Computer Write Protection Foundations 2 About Discs Open Closed When Your Disc Is Eject Button Indicator Lamp Foundations Loading Software/Games Drive a disc missing Retry, Ignore or Cancel?Run rolcave ROLCAVE. not found Syntax error Bad commandDrive a read fail Retry, Ignore or Cancel? Type mismatch Foundations Introducing Amsdos and CP/M Load filename Drive B disc missing Retry, Ignore or CancelDisc Tape.in First Steps Using The CP/M Disc Storing Data Onto DiscCpm CLS? Back to Amsdos BewareSaving a Program in Memory onto Disc Catalog Loading From DiscEXAMPLE.BAS Copying Programs From Disc to Disc Copying Programs From Cassette to DiscCopying Programs From Disc to Cassette Copying Using Disccopy Copying Using the CP/M System Disc Copying started Reading track 0 to Copying Using CopydiscWriting track 0 to Do you want to copy another disc Y/N Aborting Checking DiscsDiscchk Chkdisc Installation Amstrad Disc Drive & Interface DDI-1 Manual Making Working Discs Backup Master Disc Basic only disc Working SYSTEM/UTILITY discTurnkey Amstrad Basic discs DISCCOPY.COM Turnkey CP/M Discs Turnkey Basic using disc suppliedTurnkey Basic onto your Working disc Creating a Turnkey CP/M System disc Configuring a CP/M Program Configuring the Output from the packageAmbiguous filename Confirm individual files Y/N ? Configuring the Input to the package Starting a Turnkey CP/M PackagePayroll Autostarting a Turnkey CP/M Package Introduction Amsdos Primer Disc Directory Amsdos filenames and filetypesConstruction of Filenames Amsdos headers Filenames on two drivesSave PROG.BAS a Save Bprog .BAS Wild cards Examples of Using Amsdos Commands in a programSaving variables and performing a Screen Dump BERT.BAS FRED1.BAS FRED2.BAS FRED3.BAK FRED3.BAS FINISH.BAS Closeout Neat Pre-empting a Garbage Collection Reference guide to Amsdos commandsWhile not EOF Wend Closein Summary of Amsdos external commands Summary of Basic commandsSave OPENOUT, Print #9, Write #9, List #9, Closeout CAT DIR CPMDisc DISC.IN REN ERATape TAPE.IN Copying Files File Copying proceduresAmsdos files with headers Ascii files File has a header Amstrad Reference guide to Amsdos Error Messages Drive Drive disc is write protected Drive Drive disc missingDrive Drive read fail Drive Drive write fail CP/M Primer Operating with CP/MCP/M system tracks Configuration Sector Console control codesLogging in a disc Switching default drives Direct Console CommandsDIR command ERA command REN command Transient commandsType command Peripheral Management Single file copying File and disc copyingWhole disc copiers and checkers Cassette files Stat System Management Do you want to update your system disc Y/N SetupStat SECRET.BAS $DIR Is this correct Y/N Amsdos Disc GenerationFormat Format D Format I Format Advanced programming BootgenMovcpm Sysgen Amstrad Disc Drive & Interface DDI-1 Manual Introduction to Logo What is Logo Getting Started Dr. Logo Repeat 4 fd 60 rt Procedures with parametersTo square Repeat 4 fd 60 rt 90 end To squareanysize side repeat 4 fd side rt 90 end Editing programs and procedures Using Variables to remember valuesCs squareanysize 100 rt 45 squareanysize To triangle Repeat 3 fd edge rt 120 end Summary of Dr. Logo primitives Operating hints Ascii Word and List ProcessingChar Count First EmptypFput List Arithmetic Operations Logical Operations ?= Logo Logo Not Variables Procedures Text Screen EditingSetsplit Show Graphic Screen CleanType Dot Pal SetpalWindow Wrap Turtle Graphics Setpc Seth Setpos Workspace ManagementErn Nodes Glist RecycleGprop Plist Load Disc Files DirSave KEYBOARD, Joystick buttonp ?paddle 0 Paddle?make key rc ?key Env SoundEnt Release Repeat LabelRun Stop Catch ErrorPause Throw System Properties Headers Technical information for the user Firmware Store requirements Changing Discs Error Messages Bios messagesAmsdos messages Failed to load boot sector Common to ALL Formats Disc Organisation Jump Block Interception by Amsdos Jump Block Re-Interception by the UserReturn Parameters Intercepted Firmware Calls 132 #BC8C 133 #BC8F 134 #BC92 135 #BC95 #BC98137 #BC9B Page Appendix Glossary of Terms CP/M Dr.Logo Primitives TPA Amstrad Disc Drive & Interface DDI-1 Manual Appendix Term Limitations of Remedies Amstrad Disc Drive & Interface DDI-1 Manual Appendix Index ERA Setpos