"

 COPYRIGHT (c) 1989 by Claus Gittinger

              All Rights Reserved

 This software is furnished under a license and may be used

 only in accordance with the terms of that license and with the

 inclusion of the above copyright notice.   This software may not

 be provided or otherwise made available to, or used by, any

 other person.  No title to or ownership of the software is

 hereby transferred.

"

                              sourcePos initialPC

                              selfValue method'

       classVariableNames:'InvalidNewSignal'

       poolDictionaries:''

       category:'Kernel-Methods'

!

Block comment:'

COPYRIGHT (c) 1989 by Claus Gittinger

              All Rights Reserved

written spring 89 by claus

'!

!Block class methodsFor:'documentation'!

documentation

"

    Blocks are pieces of executable code which can be evaluated by sending

    them a value-message (''value'', ''value:'', ''value:value:'' etc).

    Blocks with arguments need a message of type ''value:arg1 ... value:argn''

    for evaluation; the number of arguments passed when evaluating must match

    the number of arguments the block was declared with otherwise an error is

    raised. Blocks without args need a ''value'' message for evaluation.

    Blocks keep a reference to the method context where the block was declared -

    this allows blocks to access the methods arguments and/or variables.

    This is also true when the method has already returned - since the

    block keeps this reference, the methods context will NOT die in this case.

    A return (via ^-statement) out of a block will force a return from the

    blocks method context (if it is still living) - this make the implementation

    of long-jumps and control structures possible.

    (If the method is not alive (i.e. has already returned), a return out of the block 

    is ignored and a simple return from the block is performed).

    Long-jump is done by defining a catchBlock as ''[^ self]''

    somewhere up in the calling-tree. Then, to do the long-jump from out of some 

    deeply nested method, simply do: ''catchBlock value''.

    Instance variables:

    code        <not_an_object>   the function pointer if its a compiled block

    flags       <SmallInteger>    special flag bits coded in a number

    byteCode    <ByteArray>       bytecode of home method if its an interpreted block

    home        <Context>         the context where this block was created (i.e. defined)

                                  this may be a BlockContext or a methodContext

    nargs       <SmallInteger>    the number of arguments the block expects

    sourcePos   <SmallInteger>    the character poistion of its source, in chars

                                  relative to methods source beginning

    initialPC   <SmallInteger>    the start position within the byteCode

                                  for compiled blocks, this is nil.

    literals    <Array>           the blocks literal array

    selfValue   <Object>          value to use for self if its a copying block

    method      <Method>          method where block was created (cheap blocks only)

    NOTICE: layout known by runtime system and compiler - do not change

"

! !

!Block class methodsFor:'initialization' !

initialize

    "setup the signals"

    InvalidNewSignal isNil ifTrue:[

        InvalidNewSignal := (Signal new).

        InvalidNewSignal mayProceed:false.

        InvalidNewSignal notifierString:'blocks are only created by the system'.

    ]

! !

!Block class methodsFor:'queries'!

isBuiltInClass

    "this class is known by the run-time-system"

    ^ true

! !

!Block class methodsFor:'instance creation'!

code:codeAddress byteCode:bCode nargs:numArgs sourcePosition:sourcePos initialPC:initialPC literals:literals dynamic:dynamic

    "create a new cheap (homeless) block.

     Not for public use - special hook for the compiler."

    |newBlock|

    newBlock := super basicNew code:codeAddress 

                           byteCode:bCode

                              nargs:numArgs

                     sourcePosition:sourcePos

                          initialPC:initialPC

                           literals:literals

                            dynamic:dynamic.

    ^ newBlock

!

new

    "catch creation of blocks - only the system creates blocks"

    InvalidNewSignal raise.

    ^ nil

!

new:size

    "catch creation of blocks - only the system creates blocks"

    InvalidNewSignal raise.

    ^ nil

! !

!Block methodsFor:'testing'!

isBlock

    "return true, if this is a block - yes I am"

    ^ true

! !

!Block methodsFor:'accessing'!

nargs

    "return the number of arguments I expect for evaluation"

    ^ nargs

!

selfValue

    "return the copied self"

    ^ selfValue

! !

!Block methodsFor:'private accessing'!

code:codeAddress byteCode:bCode nargs:numArgs sourcePosition:srcPos initialPC:iPC literals:lits dynamic:dynamic

    "set all relevant internals"

    self code:codeAddress.

    byteCode := bCode.

    nargs := numArgs.

    sourcePos := srcPos.

    initialPC := iPC.

    literals := lits.

    self dynamic:dynamic

!

nargs:numArgs

    "set the number of arguments I expect for evaluation - DANGER ALERT"

    nargs := numArgs

!

sourcePosition:position 

    "set the position of the source within my method"

    sourcePos := position

!

initialPC:initial 

    "set the initial pc for evaluation - DANGER ALERT"

    initialPC := initial

! !

!Block methodsFor:'error handling'!

argumentCountError:numberGiven

    "report that the number of arguments given does not match the number expected"

    self error:('Block got ' , numberGiven printString ,

                ' args while ' , nargs printString , ' where expected')

!

invalidMethod

    "this error is triggered by the interpreter when a non-Block object

     is about to be executed.

     In this case, the VM sends this to the bad method (the receiver).

     Can only happen when the Compiler/runtime system is broken or

     someone played around."

    self error:'invalid block - not executable'

!

tooManySendArguments

    "this error is triggered, when a method tries to perform a send with

     more arguments than supported by the interpreter - this can only

     happen, if the compiler has been changed without updating the VM."

    self error:'too many send args - should not happen'

!

tooManyArguments

    "this error is triggered, when a method is called with more arguments

     than supported by the interpreter - this can only happen, if the

     compiler has been changed without updating the VM."

    self error:'block has too many args - should not happen'

! !

!Block methodsFor:'evaluation'!

value

    "evaluate the receiver with no block args. The receiver must be a block without arguments."

%{  /* NOCONTEXT */

    REGISTER OBJFUNC thecode;

    OBJ home;

    extern OBJ interpret();

    if (_INST(nargs) == _MKSMALLINT(0)) {

#if defined(THIS_CONTEXT)

        if (1 /* _intVal(__pilc->ilc_lineNo) > 0 */)

            _ContextInstPtr(__thisContext)->c_lineno = __pilc->ilc_lineNo;

#endif

        thecode = _BlockInstPtr(self)->b_code;

#ifdef NEW_BLOCK_CALL

        if (thecode != (OBJFUNC)nil) {

            /* compiled machine code */

            RETURN ( (*thecode)(self, COMMA_SND) );

        }

        /* interpreted code */

        RETURN ( interpret(self, 0, nil, nil COMMA_SND, nil) );

#else

        home = _BlockInstPtr(self)->b_home;

        if (thecode != (OBJFUNC)nil) {

            /* compiled machine code */

            RETURN ( (*thecode)(home COMMA_SND) );

        }

        /* interpreted code */

        RETURN ( interpret(self, 0, nil, home COMMA_SND, nil) );

#endif

    }

%}

.

    ^ self argumentCountError:0

!

value:arg

    "evaluate the receiver with one argument. The receiver must be a 1-arg block."

%{  /* NOCONTEXT */

    REGISTER OBJFUNC thecode;

    OBJ home;

    extern OBJ interpret();

    if (_INST(nargs) == _MKSMALLINT(1)) {

#if defined(THIS_CONTEXT)

        if (1 /* _intVal(__pilc->ilc_lineNo) > 0 */)

            _ContextInstPtr(__thisContext)->c_lineno = __pilc->ilc_lineNo;

#endif

        thecode = _BlockInstPtr(self)->b_code;

#ifdef NEW_BLOCK_CALL

        if (thecode != (OBJFUNC)nil) {

            RETURN ( (*thecode)(self COMMA_SND, arg) );

        }

        /* interpreted code */

        RETURN ( interpret(self, 1, nil, nil COMMA_SND, nil, arg) );

#else

        home = _BlockInstPtr(self)->b_home;

        if (thecode != (OBJFUNC)nil) {

            RETURN ( (*thecode)(home COMMA_SND, arg) );

        }

        /* interpreted code */

        RETURN ( interpret(self, 1, nil, home COMMA_SND, nil, arg) );

#endif

    }

%}

.

    ^ self argumentCountError:1

!

value:arg1 value:arg2

    "evaluate the receiver with two arguments. The receiver must be a 2-arg block."

%{  /* NOCONTEXT */

    REGISTER OBJFUNC thecode;

    OBJ home;

    extern OBJ interpret();

    if (_INST(nargs) == _MKSMALLINT(2)) {

#if defined(THIS_CONTEXT)

        if (1 /* _intVal(__pilc->ilc_lineNo) > 0 */)

            _ContextInstPtr(__thisContext)->c_lineno = __pilc->ilc_lineNo;

#endif

        thecode = _BlockInstPtr(self)->b_code;

#ifdef NEW_BLOCK_CALL

        if (thecode != (OBJFUNC)nil) {

            RETURN ( (*thecode)(self COMMA_SND, arg1, arg2) );

        }

        RETURN ( interpret(self, 2, nil, nil COMMA_SND, nil, arg1, arg2) );

#else

        home = _BlockInstPtr(self)->b_home;

        if (thecode != (OBJFUNC)nil) {

            RETURN ( (*thecode)(home COMMA_SND, arg1, arg2) );

        }

        RETURN ( interpret(self, 2, nil, home COMMA_SND, nil, arg1, arg2) );

#endif

    }

%}

.

    ^ self argumentCountError:2

!

value:arg1 value:arg2 value:arg3

    "evaluate the receiver with three arguments. The receiver must be a 3-arg block."

%{  /* NOCONTEXT */

    REGISTER OBJFUNC thecode;

    OBJ home;

    extern OBJ interpret();

    if (_INST(nargs) == _MKSMALLINT(3)) {

#if defined(THIS_CONTEXT)

        if (1 /* _intVal(__pilc->ilc_lineNo) > 0 */)

            _ContextInstPtr(__thisContext)->c_lineno = __pilc->ilc_lineNo;

#endif

        thecode = _BlockInstPtr(self)->b_code;

#ifdef NEW_BLOCK_CALL

        if (thecode != (OBJFUNC)nil) {

            RETURN ( (*thecode)(self COMMA_SND, arg1, arg2, arg3) );

        }

        RETURN ( interpret(self, 3, nil, nil COMMA_SND, nil, arg1, arg2, arg3) );

#else

        home = _BlockInstPtr(self)->b_home;

        if (thecode != (OBJFUNC)nil) {

            RETURN ( (*thecode)(home COMMA_SND, arg1, arg2, arg3) );

        }

        RETURN ( interpret(self, 3, nil, home COMMA_SND, nil, arg1, arg2, arg3) );

#endif

    }

%}

.

    ^ self argumentCountError:3

!

value:arg1 value:arg2 value:arg3 value:arg4

    "evaluate the receiver with four arguments. The receiver must be a 4-arg block."

%{  /* NOCONTEXT */

    REGISTER OBJFUNC thecode;

    OBJ home;

    extern OBJ interpret();

    if (_INST(nargs) == _MKSMALLINT(4)) {

#if defined(THIS_CONTEXT)

        if (1 /* _intVal(__pilc->ilc_lineNo) > 0 */)

            _ContextInstPtr(__thisContext)->c_lineno = __pilc->ilc_lineNo;

#endif

        thecode = _BlockInstPtr(self)->b_code;

#ifdef NEW_BLOCK_CALL

        if (thecode != (OBJFUNC)nil) {

            RETURN ( (*thecode)(self COMMA_SND, arg1, arg2, arg3, arg4) );

        }

        RETURN ( interpret(self, 4, nil, nil COMMA_SND, nil, arg1, arg2, arg3, arg4) );

#else

        home = _BlockInstPtr(self)->b_home;

        if (thecode != (OBJFUNC)nil) {

            RETURN ( (*thecode)(home COMMA_SND, arg1, arg2, arg3, arg4) );

        }

        RETURN ( interpret(self, 4, nil, home COMMA_SND, nil, arg1, arg2, arg3, arg4) );

#endif

    }

%}

.

    ^ self argumentCountError:4

!

value:arg1 value:arg2 value:arg3 value:arg4 value:arg5

    "evaluate the receiver with four arguments. The receiver must be a 5-arg block."

%{  /* NOCONTEXT */

    REGISTER OBJFUNC thecode;

    OBJ home;

    extern OBJ interpret();

    if (_INST(nargs) == _MKSMALLINT(5)) {

#if defined(THIS_CONTEXT)

        if (1 /* _intVal(__pilc->ilc_lineNo) > 0 */)

            _ContextInstPtr(__thisContext)->c_lineno = __pilc->ilc_lineNo;

#endif

        thecode = _BlockInstPtr(self)->b_code;

#ifdef NEW_BLOCK_CALL

        if (thecode != (OBJFUNC)nil) {

            RETURN ( (*thecode)(self COMMA_SND, arg1, arg2, arg3, arg4, arg5) );

        }

        RETURN ( interpret(self, 5, nil, nil COMMA_SND, nil, arg1, arg2, arg3, arg4, arg5) );

#else

        home = _BlockInstPtr(self)->b_home;

        if (thecode != (OBJFUNC)nil) {

            RETURN ( (*thecode)(home COMMA_SND, arg1, arg2, arg3, arg4, arg5) );

        }

        RETURN ( interpret(self, 5, nil, home COMMA_SND, nil, arg1, arg2, arg3, arg4, arg5) );

#endif

    }

%}

.

    ^ self argumentCountError:5

!

value:arg1 value:arg2 value:arg3 value:arg4 value:arg5 value:arg6

    "evaluate the receiver with four arguments. The receiver must be a 6-arg block."

%{  /* NOCONTEXT */

    REGISTER OBJFUNC thecode;

    OBJ home;

    extern OBJ interpret();

    if (_INST(nargs) == _MKSMALLINT(6)) {

#if defined(THIS_CONTEXT)

        if (1 /* _intVal(__pilc->ilc_lineNo) > 0 */)

            _ContextInstPtr(__thisContext)->c_lineno = __pilc->ilc_lineNo;

#endif

        thecode = _BlockInstPtr(self)->b_code;

#ifdef NEW_BLOCK_CALL

        if (thecode != (OBJFUNC)nil) {

            RETURN ( (*thecode)(self COMMA_SND, arg1, arg2, arg3, arg4, arg5, arg6) );

        }

        RETURN ( interpret(self, 6, nil, nil COMMA_SND, nil, arg1, arg2, arg3, arg4, arg5, arg6) );

#else

        home = _BlockInstPtr(self)->b_home;

        if (thecode != (OBJFUNC)nil) {

            RETURN ( (*thecode)(home COMMA_SND, arg1, arg2, arg3, arg4, arg5, arg6) );

        }

        RETURN ( interpret(self, 6, nil, home COMMA_SND, nil, arg1, arg2, arg3, arg4, arg5, arg6) );

#endif

    }

%}

.

    ^ self argumentCountError:6

!

valueWithArguments:argArray

    "evaluate the receiver with arguments taken from argArray.

     The size of the argArray must match the number of arguments the receiver expects."

    |a1 a2 a3 a4 a5 a6 a7|

    (argArray class == Array) ifFalse:[

        ^ self error:'argument must be an array'

    ].

    (argArray size == nargs) ifFalse:[

        ^ self argumentCountError:(argArray size)

    ].

%{

    REGISTER OBJFUNC thecode;

    OBJ home;

    extern OBJ interpret();

    REGISTER OBJ *ap;

#if defined(THIS_CONTEXT)

    if (1 /* _intVal(__pilc->ilc_lineNo) > 0 */)

        _ContextInstPtr(__thisContext)->c_lineno = __pilc->ilc_lineNo;

#endif

    switch (_intVal(_INST(nargs))) {

        default:

            goto error;

        case 7:

            a7 = _ArrayInstPtr(argArray)->a_element[6];

        case 6:

            a6 = _ArrayInstPtr(argArray)->a_element[5];

        case 5:

            a5 = _ArrayInstPtr(argArray)->a_element[4];

        case 4:

            a4 = _ArrayInstPtr(argArray)->a_element[3];

        case 3:

            a3 = _ArrayInstPtr(argArray)->a_element[2];

        case 2:

            a2 = _ArrayInstPtr(argArray)->a_element[1];

        case 1:

            a1 = _ArrayInstPtr(argArray)->a_element[0];

        case 0:

            break;

    }

    thecode = _BlockInstPtr(self)->b_code;

#ifdef NEW_BLOCK_CALL

    if (thecode != (OBJFUNC)nil) {

        RETURN ( (*thecode)(self COMMA_SND, a1, a2, a3, a4, a5, a6, a7) );

    }

    RETURN ( interpret(self, _intVal(_INST(nargs)), nil, nil COMMA_SND, nil, 

                       a1, a2, a3, a4, a5, a6, a7) );

#else

    home = _BlockInstPtr(self)->b_home;

    if (thecode != (OBJFUNC)nil) {