-- JaMExecDefs.mesa
-- Written by John Warnock, January, 1978.
-- Last changed by Doug Wyatt, February 10, 1981  6:53 PM

DIRECTORY
	JaMMasterDefs USING [Object];

JaMExecDefs: DEFINITIONS = {
OPEN JaMMasterDefs;

-- The following routines provide for the control of execution. It is
-- assumed that the current stack is the execution stack.

-- "Execute" executes the undiscriminated object.
Execute: PROCEDURE;

-- "If" is the implementation of the testing instruction.
-- Two operands are required: an Object and a Boolean. If the
-- Boolean is TRUE then the object is executed otherwise the 
-- object is popped.
If: PROCEDURE;

-- "IfElse" is the implementation of the two way conditional execution
-- instruction. Three operands are required: Object1,Object2, and a  Boolean.
-- If the Boolean is TRUE then Object2 is executed otherwise Object1 is 
-- executed.
IfElse: PROCEDURE;

-- "Rept" is the "loop for count" instruction. Two operands are required:
-- an IntegerType and an Object. The Object is executed for the number
-- of times indicated by the Integer. (0 for Negative).
Rept: PROCEDURE;

-- "For" is based on the Algol "for i _ i step j until k do" instruction.
-- Four operands are required: three IntegerTypes and an Object.
-- The Object is executed for each iteration, with the current loop index on
--  the operand stack. 
For: PROCEDURE;

-- "Loop" is the "loop forever" instruction. One operand is required:
-- The Object is executed until an ".exit" command is executed.
Loop: PROCEDURE;

-- "Exit" procedure pops the executionstack until the inner most loop is 
-- terminated. (until a mark is encountered).
Exit: PROCEDURE;

-- "Stop" procedure pops the executionstack and checkpoints the VM.
Stop: PROCEDURE;

-- "JaMError" is an error that is caught by execution control.  The
-- restore parameter is used to indicate to execution control if it 
-- is safe to restore the operand stack. execute is the StringType Object
-- that will be pushed onto the execution stack.
JaMError: ERROR[execute: StringType Object, restore: BOOLEAN];

-- Here are a number of possible error strings

badbcdfile: StringType Object;
badname: StringType Object;
commandovrflw: StringType Object;
dictfull: StringType Object;
longname: StringType Object;
nostream: StringType Object;
overflow: StringType Object;
rangechk: StringType Object;
sizechk: StringType Object;
stkovrflw: StringType Object;
stkundflw: StringType Object;
syntaxerr: StringType Object;
typechk: StringType Object;
undefkey: StringType Object;
unregistered: StringType Object;

SetWakeUp: PROCEDURE[BOOLEAN];
GetWakeUp: PROCEDURE RETURNS[BOOLEAN];

JaMExec: PROGRAM;

}.

DKW  March 27, 1980  6:15 PM
	added JaMExec: PROGRAM;

DKW  September 29, 1980  11:49 AM
	changed WakeUp to SetWakeUp, added GetWakeUp
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