
DIRECTORY 
Ascii, IO, EditedStream, RefTab, Rope, SafeStorage, SimpleStreams;

SimpleStreamsImpl: CEDAR MONITOR
IMPORTS EditedStream, IO, RefTab, SafeStorage
EXPORTS SimpleStreams =
BEGIN OPEN SimpleStreams; 

TypeReg: TYPE = RECORD [type: SafeStorage.Type, p: CreateProcType];
types: LIST OF TypeReg м NIL;  --there will be only a very small number of registered types 
tab: RefTab.Ref м RefTab.Create[3]; --registered window systems
default: REF м NIL;  --existence checked before assignment

Find: PROC [ws: REF] RETURNS [found: REFмNIL, proc: CreateProcTypeмNIL] = {
WITH RefTab.Fetch[tab, ws].val SELECT FROM
pr: REF CreateProcType => {RETURN[ws, prн]};
ENDCASE => {};
WITH ws SELECT FROM
la: LIST OF ATOM => --recurse on elements of list
FOR l: LIST OF ATOM м la, l.rest WHILE l#NIL DO
[found, proc] м Find[l.first];
IF found#NIL THEN RETURN;
ENDLOOP;
lra: LIST OF REF ANY =>  --recurse on elements of list
FOR l: LIST OF REF ANY м lra, l.rest WHILE l#NIL DO
[found, proc] м Find[l.first];
IF found#NIL THEN RETURN;
ENDLOOP;
a: ATOM => RETURN; --prevent endcase: not worth going through types
ENDCASE => {
IF ws#NIL AND types#NIL THEN {
type: SafeStorage.Type м SafeStorage.GetReferentType[ws];
FOR l: LIST OF TypeReg м types, l.rest WHILE l#NIL DO
IF type=l.first.type THEN RETURN [ws, l.first.p];
ENDLOOP;
FOR l: LIST OF TypeReg м types, l.rest WHILE l#NIL DO
IF SafeStorage.EquivalentTypes[type, l.first.type] THEN RETURN [ws, l.first.p]; 
ENDLOOP;
};
};
};

Create: PUBLIC PROC [header: Rope.ROPE м NIL, echo: BOOL м TRUE, windowSystem: REF м NIL] RETURNS [in, out, err: IO.STREAM, hasEcho: BOOL] = {
ws: REF м NIL; proc: CreateProcType м NIL;
IF windowSystem#NIL THEN [ws, proc] м Find[windowSystem];
IF proc=NIL THEN {
[ws, proc] м Find[default];
IF proc=NIL THEN proc м NoWhereCreate;
};
[in, out, err, hasEcho] м proc[header, echo, ws];  
IF echo AND ~hasEcho THEN 
in м EditedStream.Create[in: in, echoTo: out, deliverWhen: DeliverOnCrOrLf];
IF err=NIL THEN err м out;
};

SetCurrentCreate: PUBLIC PROC [windowSystem: REF, scope: REF м NIL] = {
ws: REF м NIL; proc: CreateProcType м NIL;
[ws, proc] м Find[windowSystem];
IF ws#NIL AND proc#NIL THEN default м ws;
};

ImplementCreate: PUBLIC ENTRY PROC [windowSystem: REF, create: CreateProcType, setCurrent: BOOL м TRUE] = {
ENABLE UNWIND => NULL;
IF create#NIL THEN {
WITH windowSystem SELECT FROM
tr: REF SafeStorage.Type => types м CONS[TypeReg[trн, create], types];
ENDCASE => [] м RefTab.Store[tab, windowSystem, NEW[CreateProcType м create]];
IF setCurrent THEN SetCurrentCreate[windowSystem];
};
};

DeliverOnCrOrLf: EditedStream.DeliverWhenProc = {
IF char = Ascii.DEL THEN {
RETURN [appendChar: FALSE, activate: FALSE];
}; 
RETURN [appendChar: TRUE, activate: char = '\l OR char = '\r] 
};

NoWhereCreate: CreateProcType = {
in м IO.noInputStream; out м err м IO.noWhereStream; hasEcho м echo;
};

ImplementCreate[NIL, NoWhereCreate, TRUE];
END.

  f  
SimpleStreamsImpl.mesa
Copyright ╙ 1988, 1992 by Xerox Corporation.  All rights reserved.
Christian Jacobi, August 26, 1988 11:12:22 am PDT
Christian Jacobi, October 6, 1988 3:08:15 pm PDT
--ENTRY to protect the CONS'ing of type registrations
--prevent raising EditedStream.Rubout 
--(not an allowed error to be raised by streams; Pfui EditedStream)
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