CDSequencer.mesa (A ChipNDale module)
Copyright © 1983, 1985 by Xerox Corporation. All rights reserved.
by Christian Jacobi, June 29, 1983 2:34 pm
last edited by Christian Jacobi, July 8, 1985 4:24:50 pm PDT
Executing and queueing commands
DIRECTORY
CD,
Rope USING [ROPE];
CDSequencer: CEDAR DEFINITIONS =
BEGIN
Command: TYPE = REF CommandRec;
CommandRec:
TYPE =
RECORD [
a: ATOM ← NIL,
design: CD.Design ← NIL,
l: CD.Layer ← CD.combined,
n: CD.Number ← 0,
pos: CD.Position ← [0, 0], -- final position of command
sPos: CD.Position ← [0, 0], -- special position, start position, (exceptional: size)
orient: CD.Orientation ← CD.original,
b: BOOLEAN ← FALSE,
ref: REF ← NIL, --typically describes who issued the command (viewers data field)
data: REF ← NIL, --reserved for command implementor
fetched: --PRIVATE-- REF READONLY CommDescriptor ← NIL --private for CDSequencerImpl
];
CommandProc: TYPE = PROC[Command];
QueueMethod:
TYPE = {doQueueAndMark, doQueue, dontQueue, useDefault};
--doQueueAndMark: mark the design as changed
--the queued executions are also forked
CommDescriptor: TYPE = RECORD [p: CommandProc, qm: QueueMethod];
ExecuteProc:
PROC [comm: CDSequencer.Command ←
NIL, design:
CD.Design ←
NIL, proc: CommandProc, queue: QueueMethod ← doQueue];
--if design#NIL replaces comm.design
--proc must be global
--To transfer data to proc use: "comm: NEW[CommandRec ← [data: ..]]"
ExecuteCommand:
PROC [comm: CDSequencer.Command ←
NIL, design:
CD.Design ←
NIL, command:
ATOM ←
NIL, queue: QueueMethod ← useDefault];
--if command#NIL replaces comm.a
--if design#NIL replaces comm.design
ImplementCommand:
PROC [a:
ATOM, p: CommandProc, technology:
CD.Technology←
NIL, queue: QueueMethod ← doQueueAndMark];
--If technology is NIL implement for all technologies.
--Reimplementing the same atom in a technology overwrites the command;
--If the same atom is specified for a particular technology and all technologies,
--the more specific implementation wins independent of order.
--There is a (finite, short) list of atoms you can NOT use.
FetchCommand:
PROC [a:
ATOM, technology:
CD.Technology]
RETURNS [
REF
READONLY CommDescriptor];
--NIL if not defined
MarkChanged:
PROC [design:
CD.Design];
--the design has been changed; it should be saved some time again...
QuitCommand:
PROC [message: Rope.
ROPE];
--write message and terminates execution of the command of this process
--never returns
AbortTheCommand:
PROC [design:
CD.Design];
--called from any process
Aborted:
PROC [design:
CD.Design]
RETURNS [
BOOL];
--checks if the current command on design has been aborted
CheckAborted:
PROC [design:
CD.Design];
--IF Aborted[design] THEN SIGNAL TerminalIO.UserAbort
END.