! PATBLSEXT.REQ
! IDENT('EV1-40')
!
!<BLF/REQUIRE'PATBLF_INI'>

!++
! FACILITY:	PAT Parser
!
! ABSTRACT:
!
!	PATBLSEXT.REQ is the specification for BLISS
!	extentions used by the parser.
!
!	It also defines the conditionals used for conditional
!	compilation tests.
!
!	This file is generally language independent although
!	some applications may wish to change the manner in
!	which the conditionals for conditional compilation are
!	implemented.
!
! ENVIRONMENT:	VAX/VMS user mode
!
! AUTHOR:  H. Alcabes, CREATION DATE:  17-Feb-81
!
! MODIFIED BY:
!
!	Charlie Mitchell, 26-Oct-1981, VERSION X2.0-001
! 001 -	Add macros PATBLSEXT_DEBUGGING and PATBLSEXT_LOCAL_RECOVERY.
!	Modify enumeration macro so that can have zero enumeration
!	values.  Incorporate various modifications for SD_ definitions
!	from Brian Hetrick and Becky Will (BASIC).
!
!--

macro
    PATBLSEXT_DEBUGGING =

	!+
	! Debugging code is generated if this macro has the value
	! TRUE.  Normally debugging code is generated if running
	! BLISS-32 with /DEB unless /VARIANT=1.  The /VARIANT option
	! permits compilation with Debug symbol table records but without
	! the parser debugger.
	!-

	(%bliss (bliss32) and (%variant neq 1)) %;

macro
    PATBLSEXT_LOCAL_RECOVERY =

	!+
	! Code is generated to do local error recovery if this
	! macro has value TRUE.
	!-

	(%bliss (bliss32)) %;

macro
    PATBLSEXT_EXTRA_STACK_FIELD =

	!+
	! If this macro has value TRUE, an additional field is
	! allocated in each element of the parse stack to permit
	! application specific information in lexical tokens to be 
	! associated with particular items in the stack.
	!
	! Ada uses this field to associate comments with the parse
	! stack.  A macro in PAT_LANGSP_LIBRARY called LS_LEX_EXTRA_INFO
	! returns information from a lexical token that is placed
	! this field.  See PATPARSER.REQ for information on how
	! to access the stacked extra info.
	!-

	(%bliss (bliss32)) %;


literal
    NULL = 0;

literal
    TRUE = 1,
    FALSE = 0;

macro
    ZEROBYTE (CNT, DST) =
	ch$fill (0, (CNT), (DST)) %;

!<BLF/PAGE>

!
!   Declarations for manipulations of string descriptors
!

%if %bliss (bliss16)
%then

field
    SD_BASE =
    [0, 0, 16, 0],
    SD_LENGTH =
    [4, 0, 16, 0],
    SD_TEXT =
    [0, 0, 16, 0];

literal
    SD_SIZE = 4;

%else

field
    SD_BASE =
    [0, 0, 32, 0],
    SD_LENGTH =
    [0, 0, 32, 0],
    SD_TEXT =
    [4, 0, 32, 0];

literal
    SD_SIZE = 8;

%fi

macro
    SD_FIELDS =
	SD_BASE, SD_LENGTH, SD_TEXT %;

macro
    SD_STR =
	block [SD_SIZE, byte]

	field
	(SD_FIELDS) %;

macro
    SD_VAL (ST) =
	! Create string descriptor for string literal ST

	%if %bliss (bliss16)
	%then
	    uplit byte(%string (ST, %remaining)), %charcount (ST, %remaining)
	%else
	    %charcount(ST, %remaining), uplit byte(%string (ST, %remaining))
%fi

    %;

macro
    SD_NULL_STRING =
	! String descriptor for a null string
	0, 0 %;

macro
    SD_REF (ST) =
	! Create a pointer to a string descriptor for string literal ST
	uplit (SD_VAL (ST, %remaining))
    %;

macro
    SD_STRING_EQUAL (S1, S2) =
	begin

	local
	    D1 : ref SD_STR,
	    D2 : ref SD_STR;

	D1 = S1;
	D2 = S2;
	ch$eql (.D1 [SD_LENGTH], .D1 [SD_TEXT], .D2 [SD_LENGTH], .D2 [SD_TEXT])
	end
    %;

!<BLF/PAGE>

!
!	Macro to define enumeration types:
!
!	Example:
!
!		ENUMERATION('ARITY',0,NULLARY,UNARY,BINARY,TERNARY,LIST);
!
!	Generates:
!
!		LITERAL
!			FIRST_ARITY	=0,
!			NULLARY		=0,
!			UNARY		=1,
!			BINARY		=2,
!			TERNARY		=3,
!			LIST		=4,
!			LAST_ARITY	=4;

macro
    ENUMERATION (TYPE, STARTVAL) [] =

	compiletime
	    %name (TYPE) = (STARTVAL);

	%if %null (%remaining)
	%then

	    literal
		%name ('FIRST_', TYPE) = (STARTVAL),
		%name ('LAST_', TYPE) = (STARTVAL) - 1;

	%else

	    literal
		%name ('FIRST_', TYPE) = (STARTVAL),
		ENUM1 (%name (TYPE), %remaining),
		%name ('LAST_', TYPE) = %name (TYPE) - 1;

	%fi

    %;

macro
    ENUM1 (COUNTER) [ENUMLIT] =
	%name (ENUMLIT) = COUNTER %assign(COUNTER, COUNTER + 1) %;

! End of PATBLSEXT.REQ