Language/OS - Multiplatform Resource Library/LANGUAGE OS.iso/a_utils/flex/aflexx-a/aflex.lha/aflex/src/genB.a

Text File | 1992-12-29 | 18.3 KB | 679 lines

-- Copyright (c) 1990 Regents of the University of California.
-- All rights reserved.
--
-- This software was developed by John Self of the Arcadia project
-- at the University of California, Irvine.
--
-- Redistribution and use in source and binary forms are permitted
-- provided that the above copyright notice and this paragraph are
-- duplicated in all such forms and that any documentation,
-- advertising materials, and other materials related to such
-- distribution and use acknowledge that the software was developed
-- by the University of California, Irvine.  The name of the
-- University may not be used to endorse or promote products derived
-- from this software without specific prior written permission.
-- THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
-- IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
-- WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.

-- TITLE scanner generation
-- AUTHOR: John Self (UCI)
-- DESCRIPTION
-- NOTES does actual generation (writing) of output aflex scanners
-- $Header: /dc/uc/self/arcadia/aflex/ada/src/RCS/genB.a,v 1.25 1992/10/02 23:08:41 self Exp self $

with MISC_DEFS, TEXT_IO, MISC, INT_IO, TSTRING, PARSE_TOKENS;
with SCANNER, SKELETON_MANAGER, EXTERNAL_FILE_MANAGER; use MISC_DEFS, TEXT_IO,
  TSTRING, PARSE_TOKENS, EXTERNAL_FILE_MANAGER;

package body GEN is
  INDENT_LEVEL : INTEGER := 0;  -- each level is 4 spaces

  MAX_SHORT    : constant INTEGER := 32767;
  procedure INDENT_UP is
  begin
    INDENT_LEVEL := INDENT_LEVEL + 1;
  end INDENT_UP;
  pragma INLINE(INDENT_UP);
  procedure INDENT_DOWN is
  begin
    INDENT_LEVEL := INDENT_LEVEL - 1;
  end INDENT_DOWN;
  pragma INLINE(INDENT_DOWN);

  procedure SET_INDENT(INDENT_VAL : in INTEGER) is
  begin
    INDENT_LEVEL := INDENT_VAL;
  end SET_INDENT;


  -- indent to the current level

  procedure DO_INDENT is
    I : INTEGER := INDENT_LEVEL*4;
  begin
    while (I >= 8) loop
      TEXT_IO.PUT(ASCII.HT);
      I := I - 8;
    end loop;

    while (I > 0) loop
      TEXT_IO.PUT(' ');
      I := I - 1;
    end loop;
  end DO_INDENT;

  -- generate the code to keep backtracking information

  procedure GEN_BACKTRACKING is
  begin
    if (NUM_BACKTRACKING = 0) then
      return;
    end if;

    INDENT_PUTS("if ( yy_accept(yy_current_state) /= 0 ) then");

    INDENT_UP;
    INDENT_PUTS("yy_last_accepting_state := yy_current_state;");
    INDENT_PUTS("yy_last_accepting_cpos := yy_cp;");
    INDENT_DOWN;
    INDENT_PUTS("end if;");
  end GEN_BACKTRACKING;

  -- generate the code to perform the backtrack

  procedure GEN_BT_ACTION is
  begin
    if (NUM_BACKTRACKING = 0) then
      return;
    end if;

    SET_INDENT(4);

    INDENT_PUTS("when 0 => -- must backtrack");
    INDENT_PUTS("-- undo the effects of YY_DO_BEFORE_ACTION");
    INDENT_PUTS("yy_ch_buf(yy_cp) := yy_hold_char;");

    if (FULLTBL) then
      INDENT_PUTS("yy_cp := yy_last_accepting_cpos + 1;");
    else

      -- backtracking info for compressed tables is taken \after/
      -- yy_cp has been incremented for the next state
      INDENT_PUTS("yy_cp := yy_last_accepting_cpos;");
    end if;

    INDENT_PUTS("yy_current_state := yy_last_accepting_state;");
    INDENT_PUTS("goto next_action;");
    TEXT_IO.NEW_LINE;

    SET_INDENT(0);
  end GEN_BT_ACTION;

  -- generate equivalence-class table

  procedure GENECS is
    I       : INTEGER;
    NUMROWS : INTEGER;
    use TEXT_IO;
  begin
    TEXT_IO.PUT("yy_ec : constant array(CHARACTER'FIRST..");
    TEXT_IO.PUT_LINE("CHARACTER'LAST) of short :=");
    TEXT_IO.PUT_LINE("    (   0,");

    for CHAR_COUNT in 1 .. CSIZE loop
      if (CASEINS and ((CHAR_COUNT >= CHARACTER'POS('A')) and (CHAR_COUNT <=
        CHARACTER'POS('Z')))) then
        ECGROUP(CHAR_COUNT) := ECGROUP(MISC.CLOWER(CHAR_COUNT));
      end if;

      ECGROUP(CHAR_COUNT) := abs(ECGROUP(CHAR_COUNT));
      MISC.MKDATA(ECGROUP(CHAR_COUNT));
    end loop;

    MISC.DATAEND;

    if (TRACE) then
      TEXT_IO.NEW_LINE(STANDARD_ERROR);
      TEXT_IO.NEW_LINE(STANDARD_ERROR);
      TEXT_IO.PUT(STANDARD_ERROR, "Equivalence Classes:");
      TEXT_IO.NEW_LINE(STANDARD_ERROR);
      TEXT_IO.NEW_LINE(STANDARD_ERROR);
      NUMROWS := (CSIZE + 1)/8;

      for J in 1 .. NUMROWS loop
        I := J;
        while (I <= CSIZE) loop
          TSTRING.PUT(STANDARD_ERROR, MISC.READABLE_FORM(CHARACTER'VAL(I)));
          TEXT_IO.PUT(STANDARD_ERROR, " = ");
          INT_IO.PUT(STANDARD_ERROR, ECGROUP(I), 1);
          TEXT_IO.PUT(STANDARD_ERROR, "   ");
          I := I + NUMROWS;
        end loop;
        TEXT_IO.NEW_LINE(STANDARD_ERROR);
      end loop;
    end if;
  end GENECS;

  -- generate the code to find the action number

  procedure GEN_FIND_ACTION is
  begin
    INDENT_PUTS("yy_act := yy_accept(yy_current_state);");
  end GEN_FIND_ACTION;

  -- genftbl - generates full transition table

  procedure GENFTBL is
    END_OF_BUFFER_ACTION : INTEGER := NUM_RULES + 1;
    -- *everything* is done in terms of arrays starting at 1, so provide
    -- a null entry for the zero element of all C arrays
    use TEXT_IO;
  begin
    TEXT_IO.PUT("yy_accept : constant array(0..");
    INT_IO.PUT(LASTDFA, 1);
    TEXT_IO.PUT_LINE(") of short :=");
    TEXT_IO.PUT_LINE("    (   0,");

    DFAACC(END_OF_BUFFER_STATE).DFAACC_STATE := END_OF_BUFFER_ACTION;

    for I in 1 .. LASTDFA loop
      declare
        ANUM : INTEGER := DFAACC(I).DFAACC_STATE;
      begin
        MISC.MKDATA(ANUM);

        if (TRACE and (ANUM /= 0)) then
          TEXT_IO.PUT(STANDARD_ERROR, "state # ");
          INT_IO.PUT(STANDARD_ERROR, I, 1);
          TEXT_IO.PUT(STANDARD_ERROR, " accepts: [");
          INT_IO.PUT(STANDARD_ERROR, ANUM, 1);
          TEXT_IO.PUT(STANDARD_ERROR, "]");
          TEXT_IO.NEW_LINE(STANDARD_ERROR);
        end if;
      end;
    end loop;

    MISC.DATAEND;

    if (USEECS) then
      GENECS;
    end if;

  -- don't have to dump the actual full table entries - they were created
  -- on-the-fly
  end GENFTBL;

  -- generate the code to find the next compressed-table state

  procedure GEN_NEXT_COMPRESSED_STATE is
  begin
    if (USEECS) then
      INDENT_PUTS("yy_c := yy_ec(yy_ch_buf(yy_cp));");
    else
      INDENT_PUTS("yy_c := yy_ch_buf(yy_cp);");
    end if;

    -- save the backtracking info \before/ computing the next state
    -- because we always compute one more state than needed - we
    -- always proceed until we reach a jam state
    GEN_BACKTRACKING;

    INDENT_PUTS(
      "while ( yy_chk(yy_base(yy_current_state) + yy_c) /= yy_current_state ) loop"
      );
    INDENT_UP;
    INDENT_PUTS("yy_current_state := yy_def(yy_current_state);");

    if (USEMECS) then

      -- we've arrange it so that templates are never chained
      -- to one another.  This means we can afford make a
      -- very simple test to see if we need to convert to
      -- yy_c's meta-equivalence class without worrying
      -- about erroneously looking up the meta-equivalence
      -- class twice
      DO_INDENT;

      -- lastdfa + 2 is the beginning of the templates
      TEXT_IO.PUT("if ( yy_current_state >= ");
      INT_IO.PUT(LASTDFA + 2, 1);
      TEXT_IO.PUT_LINE(" ) then");

      INDENT_UP;
      INDENT_PUTS("yy_c := yy_meta(yy_c);");
      INDENT_DOWN;
      INDENT_PUTS("end if;");
    end if;

    INDENT_DOWN;
    INDENT_PUTS("end loop;");

    INDENT_PUTS("yy_current_state := yy_nxt(yy_base(yy_current_state) + yy_c);")
      ;
    INDENT_DOWN;
  end GEN_NEXT_COMPRESSED_STATE;

  -- generate the code to find the next match

  procedure GEN_NEXT_MATCH is
  -- note - changes in here should be reflected in get_next_state
  begin
    if (FULLTBL) then
      INDENT_PUTS(
        "yy_current_state := yy_nxt(yy_current_state, yy_ch_buf(yy_cp));");
      INDENT_PUTS("while ( yy_current_state > 0 ) loop");
      INDENT_UP;
      INDENT_PUTS("yy_cp := yy_cp + 1;");
      INDENT_PUTS(
        "yy_current_state := yy_nxt(yy_current_state, yy_ch_buf(yy_cp));");
      INDENT_DOWN;
      INDENT_PUTS("end loop;");

      if (NUM_BACKTRACKING > 0) then
        GEN_BACKTRACKING;
        TEXT_IO.NEW_LINE;
      end if;

      TEXT_IO.NEW_LINE;
      INDENT_PUTS("yy_current_state := -yy_current_state;");
    else

      -- compressed
      INDENT_PUTS("loop");

      INDENT_UP;

      GEN_NEXT_STATE;

      INDENT_PUTS("yy_cp := yy_cp + 1;");

      if (INTERACTIVE) then
        TEXT_IO.PUT("if ( yy_base(yy_current_state) = ");
        INT_IO.PUT(JAMBASE, 1);
      else
        TEXT_IO.PUT("if ( yy_current_state = ");
        INT_IO.PUT(JAMSTATE, 1);
      end if;

      TEXT_IO.PUT_LINE(" ) then");
      TEXT_IO.PUT_LINE("    exit;");
      TEXT_IO.PUT_LINE("end if;");

      INDENT_DOWN;

      DO_INDENT;

      TEXT_IO.PUT_LINE("end loop;");

      if (not INTERACTIVE) then
        INDENT_PUTS("yy_cp := yy_last_accepting_cpos;");
        INDENT_PUTS("yy_current_state := yy_last_accepting_state;");
      end if;
    end if;
  end GEN_NEXT_MATCH;

  -- generate the code to find the next state

  procedure GEN_NEXT_STATE is
  -- note - changes in here should be reflected in get_next_match
  begin
    INDENT_UP;
    if (FULLTBL) then
      INDENT_PUTS("yy_current_state := yy_nxt(yy_current_state,");
      INDENT_PUTS("                    yy_ch_buf(yy_cp));");
      GEN_BACKTRACKING;
    else
      GEN_NEXT_COMPRESSED_STATE;
    end if;
  end GEN_NEXT_STATE;

  -- generate the code to find the start state

  procedure GEN_START_STATE is
  begin
    INDENT_PUTS("yy_current_state := yy_start;");

    if (BOL_NEEDED) then
      INDENT_PUTS("if ( yy_ch_buf(yy_bp-1) = ASCII.LF ) then");
      INDENT_UP;
      INDENT_PUTS("yy_current_state := yy_current_state + 1;");
      INDENT_DOWN;
      INDENT_PUTS("end if;");
    end if;

  end GEN_START_STATE;

  -- gentabs - generate data statements for the transition tables

  procedure GENTABS is
    I, J, K, NACC, TOTAL_STATES : INTEGER;
    ACCSET, ACC_ARRAY           : INT_PTR;
    ACCNUM                      : INTEGER;
    END_OF_BUFFER_ACTION        : INTEGER := NUM_RULES + 1;
    -- *everything* is done in terms of arrays starting at 1, so provide
    -- a null entry for the zero element of all C arrays

    C_LONG_DECL                 : STRING(1 .. 44) :=
      "static const long int %s[%d] =\n    {   0,\n";
    C_SHORT_DECL                : STRING(1 .. 45) :=
      "static const short int %s[%d] =\n    {   0,\n";
    C_CHAR_DECL                 : STRING(1 .. 40) :=
      "static const char %s[%d] =\n    {   0,\n";
  begin
    ACC_ARRAY := ALLOCATE_INTEGER_ARRAY(CURRENT_MAX_DFAS);
    NUMMT := 0;

    -- the compressed table format jams by entering the "jam state",
    -- losing information about the previous state in the process.
    -- In order to recover the previous state, we effectively need
    -- to keep backtracking information.
    NUM_BACKTRACKING := NUM_BACKTRACKING + 1;

    DFAACC(END_OF_BUFFER_STATE).DFAACC_STATE := END_OF_BUFFER_ACTION;

    for CNT in 1 .. LASTDFA loop
      ACC_ARRAY(CNT) := DFAACC(CNT).DFAACC_STATE;
    end loop;


    ACC_ARRAY(LASTDFA + 1) := 0;

    -- add accepting number for the jam state

    -- spit out ALIST array, dumping the accepting numbers.

    -- "lastdfa + 2" is the size of ALIST; includes room for arrays
    -- beginning at 0 and for "jam" state
    K := LASTDFA + 2;

    TEXT_IO.PUT("yy_accept : constant array(0..");
    INT_IO.PUT(K - 1, 1);
    TEXT_IO.PUT_LINE(") of short :=");
    TEXT_IO.PUT_LINE("    (   0,");
    for CNT in 1 .. LASTDFA loop
      MISC.MKDATA(ACC_ARRAY(CNT));

      if (TRACE and (ACC_ARRAY(CNT) /= 0)) then
        TEXT_IO.PUT(STANDARD_ERROR, "state # ");
        INT_IO.PUT(STANDARD_ERROR, CNT, 1);
        TEXT_IO.PUT(STANDARD_ERROR, " accepts: [");
        INT_IO.PUT(STANDARD_ERROR, ACC_ARRAY(CNT), 1);
        TEXT_IO.PUT(STANDARD_ERROR, ']');
        TEXT_IO.NEW_LINE(STANDARD_ERROR);
      end if;
    end loop;

    -- add entry for "jam" state
    MISC.MKDATA(ACC_ARRAY(LASTDFA + 1));

    MISC.DATAEND;

    if (USEECS) then
      GENECS;
    end if;

    if (USEMECS) then

      -- write out meta-equivalence classes (used to index templates with)
      if (TRACE) then
        TEXT_IO.NEW_LINE(STANDARD_ERROR);
        TEXT_IO.NEW_LINE(STANDARD_ERROR);
        TEXT_IO.PUT_LINE(STANDARD_ERROR, "Meta-Equivalence Classes:");
      end if;

      TEXT_IO.PUT("yy_meta : constant array(0..");
      INT_IO.PUT(NUMECS, 1);
      TEXT_IO.PUT_LINE(") of short :=");
      TEXT_IO.PUT_LINE("    (   0,");
      for CNT in 1 .. NUMECS loop
        if (TRACE) then
          INT_IO.PUT(STANDARD_ERROR, CNT, 1);
          TEXT_IO.PUT(STANDARD_ERROR, " = ");
          INT_IO.PUT(STANDARD_ERROR, abs(TECBCK(CNT)), 1);
          TEXT_IO.NEW_LINE(STANDARD_ERROR);
        end if;
        MISC.MKDATA(abs(TECBCK(CNT)));
      end loop;

      MISC.DATAEND;
    end if;

    TOTAL_STATES := LASTDFA + NUMTEMPS;

    TEXT_IO.PUT("yy_base : constant array(0..");
    INT_IO.PUT(TOTAL_STATES, 1);
    if (TBLEND > MAX_SHORT) then
      TEXT_IO.PUT_LINE(") of integer :=");
    else
      TEXT_IO.PUT_LINE(") of short :=");
    end if;
    TEXT_IO.PUT_LINE("    (   0,");

    for CNT in 1 .. LASTDFA loop
      declare
        D : INTEGER := DEF(CNT);
      begin
        if (BASE(CNT) = JAMSTATE_CONST) then
          BASE(CNT) := JAMBASE;
        end if;

        if (D = JAMSTATE_CONST) then
          DEF(CNT) := JAMSTATE;
        else
          if (D < 0) then

            -- template reference
            TMPUSES := TMPUSES + 1;
            DEF(CNT) := LASTDFA - D + 1;
          end if;
        end if;
        MISC.MKDATA(BASE(CNT));
      end;
    end loop;

    -- generate jam state's base index
    I := LASTDFA + 1;
    MISC.MKDATA(BASE(I));

    -- skip jam state
    I := I + 1;

    for CNT in I .. TOTAL_STATES loop
      MISC.MKDATA(BASE(CNT));
      DEF(CNT) := JAMSTATE;
    end loop;

    MISC.DATAEND;

    TEXT_IO.PUT("yy_def : constant array(0..");
    INT_IO.PUT(TOTAL_STATES, 1);
    if (TBLEND > MAX_SHORT) then
      TEXT_IO.PUT_LINE(") of integer :=");
    else
      TEXT_IO.PUT_LINE(") of short :=");
    end if;
    TEXT_IO.PUT_LINE("    (   0,");

    for CNT in 1 .. TOTAL_STATES loop
      MISC.MKDATA(DEF(CNT));
    end loop;

    MISC.DATAEND;
    TEXT_IO.PUT("yy_nxt : constant array(0..");
    INT_IO.PUT(TBLEND, 1);
    if (LASTDFA > MAX_SHORT) then
      TEXT_IO.PUT_LINE(") of integer :=");
    else
      TEXT_IO.PUT_LINE(") of short :=");
    end if;
    TEXT_IO.PUT_LINE("    (   0,");

    for CNT in 1 .. TBLEND loop
      if ((NXT(CNT) = 0) or (CHK(CNT) = 0)) then
        NXT(CNT) := JAMSTATE;

      -- new state is the JAM state
      end if;
      MISC.MKDATA(NXT(CNT));
    end loop;

    MISC.DATAEND;

    TEXT_IO.PUT("yy_chk : constant array(0..");
    INT_IO.PUT(TBLEND, 1);
    if (LASTDFA > MAX_SHORT) then
      TEXT_IO.PUT_LINE(") of integer :=");
    else
      TEXT_IO.PUT_LINE(") of short :=");
    end if;
    TEXT_IO.PUT_LINE("    (   0,");

    for CNT in 1 .. TBLEND loop
      if (CHK(CNT) = 0) then
        NUMMT := NUMMT + 1;
      end if;

      MISC.MKDATA(CHK(CNT));
    end loop;

    MISC.DATAEND;
  exception
    when STORAGE_ERROR =>
      MISC.AFLEXFATAL("dynamic memory failure in gentabs()");
  end GENTABS;

  -- write out a string at the current indentation level, adding a final
  -- newline

  procedure INDENT_PUTS(STR : in STRING) is
  begin
    DO_INDENT;
    TEXT_IO.PUT_LINE(STR);
  end INDENT_PUTS;

  -- do_sect3_out - dumps section 3.

  procedure DO_SECT3_OUT is
    GARBAGE : TOKEN;
  begin
    SCANNER.CALL_YYLEX := TRUE;
    GARBAGE := SCANNER.GET_TOKEN;
  end DO_SECT3_OUT;

  -- make_tables - generate transition tables
  --
  --
  -- Generates transition tables and finishes generating output file

  procedure MAKE_TABLES is
    DID_EOF_RULE      : BOOLEAN := FALSE;
    TRANS_OFFSET_TYPE : STRING(1 .. 7);
    TOTAL_TABLE_SIZE  : INTEGER := TBLEND + NUMECS + 1;
    BUF               : VSTRING;
  begin
    if (not FULLTBL) then

      -- if we used full tables this is already output
      DO_SECT3_OUT;

      -- intent of this call is to get everything up to ##
      SKELETON_MANAGER.SKELOUT;

    -- output YYLex code up to part about tables.
    end if;

    TEXT_IO.PUT("YY_END_OF_BUFFER : constant := ");
    INT_IO.PUT(NUM_RULES + 1, 1);
    TEXT_IO.PUT_LINE(";");

    INDENT_PUTS("subtype yy_state_type is integer;");
    INDENT_PUTS("yy_current_state : yy_state_type;");

    -- now output the constants for the various start conditions
    RESET(DEF_FILE, IN_FILE);

    while (not TEXT_IO.END_OF_FILE(DEF_FILE)) loop
      TSTRING.GET_LINE(DEF_FILE, BUF);
      TSTRING.PUT_LINE(BUF);
    end loop;

    if (FULLTBL) then
      GENFTBL;
    else
      GENTABS;
    end if;

    RESET(TEMP_ACTION_FILE, IN_FILE);

    -- generate code for yy_get_previous_state
    SET_INDENT(1);
    SKELETON_MANAGER.SKELOUT;

    if (BOL_NEEDED) then
      INDENT_PUTS("yy_bp : integer := yytext_ptr;");
    end if;
    SKELETON_MANAGER.SKELOUT;

    GEN_START_STATE;
    SKELETON_MANAGER.SKELOUT;
    GEN_NEXT_STATE;
    SKELETON_MANAGER.SKELOUT;

    SET_INDENT(2);

    INDENT_PUTS("yy_bp := yy_cp;");

    GEN_START_STATE;
    GEN_NEXT_MATCH;

    SKELETON_MANAGER.SKELOUT;

    SET_INDENT(3);
    GEN_FIND_ACTION;

    SET_INDENT(1);
    SKELETON_MANAGER.SKELOUT;

    INDENT_UP;
    GEN_BT_ACTION;

    MISC.ACTION_OUT;
    MISC.ACTION_OUT;

    -- generate cases for any missing EOF rules
    for I in 1 .. LASTSC loop
      if (not SCEOF(I)) then
        DO_INDENT;
        if (not DID_EOF_RULE) then
          TEXT_IO.PUT("when ");
        else
          TEXT_IO.PUT_LINE("|");
        end if;
        TEXT_IO.PUT("YY_END_OF_BUFFER + ");
        TSTRING.PUT(SCNAME(I));
        TEXT_IO.PUT(" + 1 ");
        DID_EOF_RULE := TRUE;
      end if;
    end loop;
    if (DID_EOF_RULE) then
      TEXT_IO.PUT_LINE("=> ");
    end if;

    if (DID_EOF_RULE) then
      INDENT_UP;
      INDENT_PUTS("return End_Of_Input;");
      INDENT_DOWN;
    end if;

    SKELETON_MANAGER.SKELOUT;

    -- copy remainder of input to output
    MISC.LINE_DIRECTIVE_OUT;
    DO_SECT3_OUT;

  -- copy remainder of input, after ##, to the scanner file.
  end MAKE_TABLES;

end GEN;