Subversion Repositories Kolibri OS

(*

    BSD 2-Clause License

    Copyright (c) 2018, 2019, Anton Krotov

    All rights reserved.

*)

MODULE SCAN;

IMPORT TXT := TEXTDRV, AVL := AVLTREES, ARITH, S := STRINGS;

CONST

    LEXLEN = 1024;

    lxUNDEF*   =  0;  lxIDENT*   =  1;  lxINTEGER*   =  2;  lxHEX*     =  3;

    lxCHAR*    =  4;  lxFLOAT*   =  5;  lxSTRING*    =  6;  lxCOMMENT* =  7;

    lxEOF*     =  8;

    lxPLUS*    = 21;  lxMINUS*   = 22;  lxMUL*       = 23;  lxSLASH*   = 24;

    lxNOT*     = 25;  lxAND*     = 26;  lxPOINT*     = 27;  lxCOMMA*   = 28;

    lxSEMI*    = 29;  lxBAR*     = 30;  lxLROUND*    = 31;  lxLSQUARE* = 32;

    lxLCURLY*  = 33;  lxCARET*   = 34;  lxEQ*        = 35;  lxNE*      = 36;

    lxLT*      = 37;  lxGT*      = 38;  lxCOLON*     = 39;  lxRROUND*  = 40;

    lxRSQUARE* = 41;  lxRCURLY*  = 42;  lxLE*        = 43;  lxGE*      = 44;

    lxASSIGN*  = 45;  lxRANGE*   = 46;

    lxKW       = 51;

    lxARRAY*   = 51;  lxBEGIN*   = 52;  lxBY*        = 53;  lxCASE*    = 54;

    lxCONST*   = 55;  lxDIV*     = 56;  lxDO*        = 57;  lxELSE*    = 58;

    lxELSIF*   = 59;  lxEND*     = 60;  lxFALSE*     = 61;  lxFOR*     = 62;

    lxIF*      = 63;  lxIMPORT*  = 64;  lxIN*        = 65;  lxIS*      = 66;

    lxMOD*     = 67;  lxMODULE*  = 68;  lxNIL*       = 69;  lxOF*      = 70;

    lxOR*      = 71;  lxPOINTER* = 72;  lxPROCEDURE* = 73;  lxRECORD*  = 74;

    lxREPEAT*  = 75;  lxRETURN*  = 76;  lxTHEN*      = 77;  lxTO*      = 78;

    lxTRUE*    = 79;  lxTYPE*    = 80;  lxUNTIL*     = 81;  lxVAR*     = 82;

    lxWHILE*   = 83;

    lxERROR01* =  -1;  lxERROR02* =  -2;  lxERROR03* =  -3;  lxERROR04* =  -4;

    lxERROR05* =  -5;  lxERROR06* =  -6;  lxERROR07* =  -7;  lxERROR08* =  -8;

    lxERROR09* =  -9;  lxERROR10* = -10;  lxERROR11* = -11;  lxERROR12* = -12;

    lxERROR13* = -13;

TYPE

    LEXSTR* = ARRAY LEXLEN OF CHAR;

    IDENT* = POINTER TO RECORD (AVL.DATA)

        s*: LEXSTR;

        offset*, offsetW*: INTEGER

    END;

    POSITION* = RECORD

        line*, col*: INTEGER

    END;

    LEX* = RECORD

        s*:         LEXSTR;

        length*:    INTEGER;

        sym*:       INTEGER;

        pos*:       POSITION;

        ident*:     IDENT;

        string*:    IDENT;

        value*:     ARITH.VALUE;

        error*:     INTEGER;

        over:       BOOLEAN

    END;

    SCANNER* = TXT.TEXT;

    KEYWORD = ARRAY 10 OF CHAR;

VAR

    vocabulary: RECORD

        KW:         ARRAY 33 OF KEYWORD;

        delimiters: ARRAY 256 OF BOOLEAN;

        idents:     AVL.NODE;

        ident:      IDENT

    END;

    upto: BOOLEAN;

PROCEDURE nodecmp (a, b: AVL.DATA): INTEGER;

    RETURN ORD(a(IDENT).s > b(IDENT).s) - ORD(a(IDENT).s < b(IDENT).s)

END nodecmp;

PROCEDURE key (VAR lex: LEX);

VAR

    L, R, M: INTEGER;

    found: BOOLEAN;

BEGIN

    L := 0;

    R := LEN(vocabulary.KW) - 1;

    found := FALSE;

    REPEAT

        M := (L + R) DIV 2;

        IF lex.s # vocabulary.KW[M] THEN

            IF lex.s > vocabulary.KW[M] THEN

                L := M + 1

            ELSE

                R := M - 1

            END

        ELSE

            found := TRUE;

            lex.sym := lxKW + M

        END

    UNTIL found OR (L > R)

END key;

PROCEDURE enterid* (s: LEXSTR): IDENT;

VAR

    newnode: BOOLEAN;

    node:    AVL.NODE;

BEGIN

    vocabulary.ident.s := s;

    vocabulary.idents := AVL.insert(vocabulary.idents, vocabulary.ident, nodecmp, newnode, node);

    IF newnode THEN

        NEW(vocabulary.ident);

        vocabulary.ident.offset  := -1;

        vocabulary.ident.offsetW := -1

    END

    RETURN node.data(IDENT)

END enterid;

PROCEDURE putchar (VAR lex: LEX; c: CHAR);

BEGIN

    IF lex.length < LEXLEN - 1 THEN

        lex.s[lex.length] := c;

        INC(lex.length);

        lex.s[lex.length] := 0X

    ELSE

        lex.over := TRUE

    END

END putchar;

PROCEDURE nextc (text: TXT.TEXT): CHAR;

BEGIN

    TXT.next(text)

    RETURN text.peak

END nextc;

PROCEDURE ident (text: TXT.TEXT; VAR lex: LEX);

VAR

    c: CHAR;

BEGIN

    c := text.peak;

    ASSERT(S.letter(c));

    WHILE S.letter(c) OR S.digit(c) DO

        putchar(lex, c);

        c := nextc(text)

    END;

    IF lex.over THEN

        lex.sym := lxERROR06

    ELSE

        lex.sym := lxIDENT;

        key(lex)

    END;

    IF lex.sym = lxIDENT THEN

        lex.ident := enterid(lex.s)

    END

END ident;

PROCEDURE number (text: TXT.TEXT; VAR lex: LEX);

VAR

    c: CHAR;

    hex: BOOLEAN;

    error: INTEGER;

BEGIN

    c := text.peak;

    ASSERT(S.digit(c));

    error := 0;

    lex.sym := lxINTEGER;

    hex := FALSE;

    WHILE S.digit(c) DO

        putchar(lex, c);

        c := nextc(text)

    END;

    WHILE S.hexdigit(c) DO

        putchar(lex, c);

        c := nextc(text);

        hex := TRUE

    END;

    IF c = "H" THEN

        putchar(lex, c);

        TXT.next(text);

        lex.sym := lxHEX

    ELSIF c = "X" THEN

        putchar(lex, c);

        TXT.next(text);

        lex.sym := lxCHAR

    ELSIF c = "." THEN

        IF hex THEN

            lex.sym := lxERROR01

        ELSE

            c := nextc(text);

            IF c # "." THEN

                putchar(lex, ".");

                lex.sym := lxFLOAT

            ELSE

                lex.sym := lxINTEGER;

                text.peak := 7FX;

                upto := TRUE

            END;

            WHILE S.digit(c) DO

                putchar(lex, c);

                c := nextc(text)

            END;

            IF c = "E" THEN

                putchar(lex, c);

                c := nextc(text);

                IF (c = "+") OR (c = "-") THEN

                    putchar(lex, c);

                    c := nextc(text)

                END;

                IF S.digit(c) THEN

                    WHILE S.digit(c) DO

                        putchar(lex, c);

                        c := nextc(text)

                    END

                ELSE

                    lex.sym := lxERROR02

                END

            END

        END

    ELSIF hex THEN

        lex.sym := lxERROR01

    END;

    IF lex.over & (lex.sym >= 0) THEN

        lex.sym := lxERROR07

    END;

    IF lex.sym = lxINTEGER THEN

        ARITH.iconv(lex.s, lex.value, error)

    ELSIF (lex.sym = lxHEX) OR (lex.sym = lxCHAR) THEN

        ARITH.hconv(lex.s, lex.value, error)

    ELSIF lex.sym = lxFLOAT THEN

        ARITH.fconv(lex.s, lex.value, error)

    END;

    CASE error OF

    |0:

    |1: lex.sym := lxERROR08

    |2: lex.sym := lxERROR09

    |3: lex.sym := lxERROR10

    |4: lex.sym := lxERROR11

    |5: lex.sym := lxERROR12

    END

END number;

PROCEDURE string (text: TXT.TEXT; VAR lex: LEX; quot: CHAR);

VAR

    c: CHAR;

    n: INTEGER;

BEGIN

    c  := nextc(text);

    n  := 0;

    WHILE (c # quot) & (c # 0X) & ~text.eol & ~text.eof DO

        putchar(lex, c);

        c := nextc(text);

        INC(n)

    END;

    IF c = quot THEN

        TXT.next(text);

        IF lex.over THEN

            lex.sym := lxERROR05

        ELSE

            IF n # 1 THEN

                lex.sym := lxSTRING

            ELSE

                lex.sym := lxCHAR;

                ARITH.setChar(lex.value, ORD(lex.s[0]))

            END

        END

    ELSE

        lex.sym := lxERROR03

    END;

    IF lex.sym = lxSTRING THEN

        lex.string := enterid(lex.s);

        lex.value.typ := ARITH.tSTRING;

        lex.value.string := lex.string

    END

END string;

PROCEDURE comment (text: TXT.TEXT);

VAR

    c: CHAR;

    cond, depth: INTEGER;

BEGIN

    cond  := 0;

    depth := 1;

    REPEAT

        c := text.peak;

        TXT.next(text);

        IF c = "*" THEN

            IF cond = 1 THEN

                cond := 0;

                INC(depth)

            ELSE

               cond := 2

            END

        ELSIF c = ")" THEN

            IF cond = 2 THEN

                DEC(depth)

            END;

            cond := 0

        ELSIF c = "(" THEN

            cond := 1

        ELSE

            cond := 0

        END

    UNTIL (depth = 0) OR text.eof

END comment;

PROCEDURE delimiter (text: TXT.TEXT; VAR lex: LEX; c: CHAR);

BEGIN

    putchar(lex, c);

    c := nextc(text);

    CASE lex.s[0] OF

    |"+":

        lex.sym := lxPLUS

    |"-":

        lex.sym := lxMINUS

    |"*":

        lex.sym := lxMUL

    |"/":

        lex.sym := lxSLASH;

        IF c = "/" THEN

            lex.sym := lxCOMMENT;

            REPEAT

                TXT.next(text)

            UNTIL text.eol OR text.eof

        END

    |"~":

        lex.sym := lxNOT

    |"&":

        lex.sym := lxAND

    |".":

        lex.sym := lxPOINT;

        IF c = "." THEN

            lex.sym := lxRANGE;

            putchar(lex, c);

            TXT.next(text)

        END

    |",":

        lex.sym := lxCOMMA

    |";":

        lex.sym := lxSEMI

    |"|":

        lex.sym := lxBAR

    |"(":

        lex.sym := lxLROUND;

        IF c = "*" THEN

            lex.sym := lxCOMMENT;

            TXT.next(text);

            comment(text)

        END

    |"[":

        lex.sym := lxLSQUARE

    |"{":

        lex.sym := lxLCURLY

    |"^":

        lex.sym := lxCARET

    |"=":

        lex.sym := lxEQ

    |"#":

        lex.sym := lxNE

    |"<":

        lex.sym := lxLT;

        IF c = "=" THEN

            lex.sym := lxLE;

            putchar(lex, c);

            TXT.next(text)

        END

    |">":

        lex.sym := lxGT;

        IF c = "=" THEN

            lex.sym := lxGE;

            putchar(lex, c);

            TXT.next(text)

        END

    |":":

        lex.sym := lxCOLON;

        IF c = "=" THEN

            lex.sym := lxASSIGN;

            putchar(lex, c);

            TXT.next(text)

        END

    |")":

        lex.sym := lxRROUND

    |"]":

        lex.sym := lxRSQUARE

    |"}":

        lex.sym := lxRCURLY

    END

END delimiter;

PROCEDURE Next* (text: SCANNER; VAR lex: LEX);

VAR

    c: CHAR;

BEGIN

    REPEAT

        c := text.peak;

        WHILE S.space(c) DO

            c := nextc(text)

        END;

        lex.s[0]     := 0X;

        lex.length   := 0;

        lex.pos.line := text.line;

        lex.pos.col  := text.col;

        lex.ident    := NIL;

        lex.over     := FALSE;

        IF S.letter(c) THEN

            ident(text, lex)

        ELSIF S.digit(c) THEN

            number(text, lex)

        ELSIF (c = '"') OR (c = "'") THEN

            string(text, lex, c)

        ELSIF vocabulary.delimiters[ORD(c)] THEN

            delimiter(text, lex, c)

        ELSIF c = 0X THEN

            lex.sym := lxEOF;

            IF text.eof THEN

                INC(lex.pos.col)

            END

        ELSIF (c = 7FX) & upto THEN

            upto := FALSE;

            lex.sym := lxRANGE;

            putchar(lex, ".");

            putchar(lex, ".");

            DEC(lex.pos.col);

            TXT.next(text)

        ELSE

            putchar(lex, c);

            TXT.next(text);

            lex.sym := lxERROR04

        END;

        IF lex.sym < 0 THEN

            lex.error := -lex.sym

        ELSE

            lex.error := 0

        END

    UNTIL lex.sym # lxCOMMENT

END Next;

PROCEDURE open* (name: ARRAY OF CHAR): SCANNER;

    RETURN TXT.open(name)

END open;

PROCEDURE close* (VAR scanner: SCANNER);

BEGIN

    TXT.close(scanner)

END close;

PROCEDURE init;

VAR

    i: INTEGER;

    delim: ARRAY 23 OF CHAR;

    PROCEDURE enterkw (VAR i: INTEGER; kw: KEYWORD);

    BEGIN

        vocabulary.KW[i] := kw;

        INC(i)

    END enterkw;

BEGIN

    upto := FALSE;

    FOR i := 0 TO 255 DO

        vocabulary.delimiters[i] := FALSE

    END;

    delim := "+-*/~&.,;|([{^=#<>:)]}";

    FOR i := 0 TO LEN(delim) - 2 DO

        vocabulary.delimiters[ORD(delim[i])] := TRUE

    END;

    i := 0;

    enterkw(i, "ARRAY");

    enterkw(i, "BEGIN");

    enterkw(i, "BY");

    enterkw(i, "CASE");

    enterkw(i, "CONST");

    enterkw(i, "DIV");

    enterkw(i, "DO");

    enterkw(i, "ELSE");

    enterkw(i, "ELSIF");

    enterkw(i, "END");

    enterkw(i, "FALSE");

    enterkw(i, "FOR");

    enterkw(i, "IF");

    enterkw(i, "IMPORT");

    enterkw(i, "IN");

    enterkw(i, "IS");

    enterkw(i, "MOD");

    enterkw(i, "MODULE");

    enterkw(i, "NIL");

    enterkw(i, "OF");

    enterkw(i, "OR");

    enterkw(i, "POINTER");

    enterkw(i, "PROCEDURE");

    enterkw(i, "RECORD");

    enterkw(i, "REPEAT");

    enterkw(i, "RETURN");

    enterkw(i, "THEN");

    enterkw(i, "TO");

    enterkw(i, "TRUE");

    enterkw(i, "TYPE");

    enterkw(i, "UNTIL");

    enterkw(i, "VAR");

    enterkw(i, "WHILE");

    NEW(vocabulary.ident);

    vocabulary.ident.s       := "";

    vocabulary.ident.offset  := -1;

    vocabulary.ident.offsetW := -1;

    vocabulary.idents := NIL

END init;

BEGIN

    init

END SCAN.