
    <<TTY.Mesa  Edited by>>
        <<Copyright (C) Xerox Corporation 1982, 1986. All rights reserved.>>
        <<Tim Diebert: December 9, 1986 11:02:39 am PST>>

    DIRECTORY
        Ascii USING [CR],
        Basics USING [UnsafeBlock],
        BasicTime USING [GMT],
        IO USING [STREAM],
        Rope USING [ROPE];

    TTY: CEDAR DEFINITIONS = BEGIN

        <<Types>>

        Handle: TYPE = REF Object;
        Object: TYPE;
        nullHandle: Handle = NIL;

        EchoClass: TYPE = {none, plain, stars};
    DateFormat: TYPE = {dateOnly, noSeconds, dateTime, full, mailDate};
    NetFormat: TYPE = {octal, hex, productSoftware};
        NumberFormat: TYPE = RECORD [
            base: [2..36] _ 10,
            zerofill: BOOLEAN _ FALSE,
            unsigned: BOOLEAN _ TRUE,
            columns: [0..255] _ 0];

        CharStatus: TYPE = {ok, stop, ignore};

        <<Signals>>

        LineOverflow: SIGNAL [s: REF TEXT] RETURNS [ns: REF TEXT];
        Rubout: SIGNAL;
        NoBackingFile: ERROR;  -- raised by BackingStream
        OutOfInstances: ERROR;  -- raised by Create
        NoDefaultInstance: ERROR;  -- raised by Create

        <<Starting and stopping>>

        Create: PROCEDURE [name: Rope.ROPE _ NIL, backingStream, ttyImpl: IO.STREAM _ NIL]
        RETURNS [h: Handle];
        Destroy: PROCEDURE [h: Handle, deleteBackingFile: BOOLEAN _ FALSE];
            <<BackingFile deleted only if subsystem created file>>

        UserAbort: PROCEDURE [h: Handle] RETURNS [yes: BOOLEAN];
        ResetUserAbort: PROCEDURE [h: Handle];
        SetUserAbort: PROCEDURE [h: Handle];

        <<CreateTTYInstance exported by TTY instance implementation>>

        CreateTTYInstance: PROCEDURE [name: Rope.ROPE, backingStream: IO.STREAM, tty: Handle] 
        RETURNS [ttyImpl, backing: IO.STREAM];

        <<Utilities>>

        BackingStream: PROCEDURE [h: Handle] RETURNS [stream: IO.STREAM];
        BlinkDisplay: PROCEDURE [h: Handle];
        CharsAvailable: PROCEDURE [h: Handle] RETURNS [number: CARDINAL];
        GetEcho: PROCEDURE [h: Handle] RETURNS [old: EchoClass];
        NewLine: PROCEDURE [h: Handle] RETURNS [yes: BOOLEAN];
        PopAlternateInputStreams: PROCEDURE [h: Handle, howMany: CARDINAL _ 1];
        PushAlternateInputStream: PROCEDURE [h: Handle, stream: IO.STREAM];
        PutBackChar: PROCEDURE [h: Handle, c: CHARACTER];
        SetBackingSize: PROCEDURE [h: Handle, size: LONG CARDINAL];
        SetEcho: PROCEDURE [h: Handle, new: EchoClass] RETURNS [old: EchoClass];

        <<Read & write procedures>>

        GetChar: PROCEDURE [h: Handle] RETURNS [c: CHARACTER];
        PutChar: PROCEDURE [h: Handle, c: CHARACTER];
        PutCR: PROCEDURE [h: Handle] = INLINE {PutChar[h, Ascii.CR]};
        PutBlank, PutBlanks: PROCEDURE [h: Handle, n: CARDINAL _ 1];
        RemoveCharacter, RemoveCharacters: PROCEDURE [h: Handle, n: CARDINAL _ 1];

        GetString: PROCEDURE [h: Handle, s: REF TEXT,
        t: PROCEDURE [c: CHARACTER] RETURNS [status: CharStatus]];
        GetEditedString: PROCEDURE [h: Handle, s: REF TEXT, 
        t: PROCEDURE [c: CHARACTER] RETURNS [status: CharStatus]]
        RETURNS [c: CHARACTER];
        PutString, PutLongString, PutText: PROCEDURE [h: Handle, s: REF TEXT];


        PutDate: PROCEDURE [h: Handle, gmt: BasicTime.GMT, format: DateFormat _ noSeconds];

        GetID, GetLine, GetPassword: PROCEDURE [h: Handle, s: REF TEXT];
        PutLine: PROCEDURE [h: Handle, s: REF TEXT];

        GetNumber: PROCEDURE [h: Handle, default: UNSPECIFIED, radix: CARDINAL,
        showDefault: BOOLEAN _ TRUE] RETURNS [n: UNSPECIFIED];
        GetLongNumber: PROCEDURE [h: Handle, default: LONG UNSPECIFIED, radix: CARDINAL,
        showDefault: BOOLEAN _ TRUE] RETURNS [n: LONG UNSPECIFIED];

        PutNumber: PROCEDURE [h: Handle, n: UNSPECIFIED, format: NumberFormat];
        PutLongNumber: PROCEDURE [h: Handle, n: LONG UNSPECIFIED, format: NumberFormat];

        GetOctal: PROCEDURE [h: Handle] RETURNS [n: UNSPECIFIED];
        GetLongOctal: PROCEDURE [h: Handle] RETURNS [n: LONG UNSPECIFIED];

        PutOctal: PROCEDURE [h: Handle, n: UNSPECIFIED];
        PutLongOctal: PROCEDURE [h: Handle, n: LONG UNSPECIFIED];

        GetDecimal: PROCEDURE [h: Handle] RETURNS [n: INTEGER];
        GetLongDecimal: PROCEDURE [h: Handle] RETURNS [n: LONG INTEGER];

        PutDecimal: PROCEDURE [h: Handle, n: INTEGER];
        PutLongDecimal: PROCEDURE [h: Handle, n: LONG INTEGER];

        PutBlock: PROCEDURE [h: Handle, block: Basics.UnsafeBlock];


        Narrow: PROC [ra: REF ANY] RETURNS [Handle];
            <<Provides NARROW function for the opaque type of Handle.>>
        END....