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Overview
Comment:Change the coverage measurement logic in the lemon-generated parser so that it only checks for coverage of state/lookahead pairs that are valid syntax. It turns out that some states are unreachable if the lookahead is not valid syntax, because the states are only reachable through a shift following a reduce, and the reduce does not happen if the lookahead is a syntax error.
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SHA3-256: 9dce46508772bd0f9e940c4d44933154044bb58c1b3511dd0143287bf795dd6b
User & Date: drh 2017-12-27 17:14:50.938
Context
2017-12-27
17:36
The previous check-in had an error in the coverage reporting logic. (Closed-Leaf check-in: ec9b19eb65 user: drh tags: lemon-improvements)
17:14
Change the coverage measurement logic in the lemon-generated parser so that it only checks for coverage of state/lookahead pairs that are valid syntax. It turns out that some states are unreachable if the lookahead is not valid syntax, because the states are only reachable through a shift following a reduce, and the reduce does not happen if the lookahead is a syntax error. (check-in: 9dce465087 user: drh tags: lemon-improvements)
16:13
In the lemon-generated parser, do not report the End-of-input character and the wildcard character as missed coverage. (check-in: 3fe964873d user: drh tags: lemon-improvements)
Changes
Unified Diff Ignore Whitespace Patch
Changes to tool/lempar.c.
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*/
#if defined(YYCOVERAGE)
static unsigned char yycoverage[YYNSTATE][YYNTOKEN];
#endif

/*
** Write into out a description of every state/lookahead combination that

** has not previously been seen by the parser.  Return the number of 


** missed state/lookahead combinations.
*/
#if defined(YYCOVERAGE)
int ParseCoverage(FILE *out){
  int i, j;
  int nMissed = 0;
  for(i=0; i<YYNSTATE; i++){

    for(j=1; j<YYNTOKEN; j++){
      if( j==YYWILDCARD ) continue;
      if( !yycoverage[i][j] ) nMissed++;
      if( out ){
        fprintf(out,"State %d lookahead %s %s\n",

           i, yyTokenName[j], yycoverage[i][j] ? "ok" : "missed");
      }
    }
  }
  return nMissed;
}
#endif









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*/
#if defined(YYCOVERAGE)
static unsigned char yycoverage[YYNSTATE][YYNTOKEN];
#endif

/*
** Write into out a description of every state/lookahead combination that
**
**   (1)  has not been used by the parser, and
**   (2)  is not a syntax error.
**
** Return the number of missed state/lookahead combinations.
*/
#if defined(YYCOVERAGE)
int ParseCoverage(FILE *out){
  int stateno, iLookAhead, i;
  int nMissed = 0;
  for(stateno=0; stateno<YYNSTATE; stateno++){
    i = yy_shift_ofst[stateno];
    for(iLookAhead=0; iLookAhead<YYNTOKEN; iLookAhead++){
      if( yy_lookahead[i]!=iLookAhead ) continue;
      if( yycoverage[stateno][iLookAhead]==0 ) nMissed++;
      if( out ){
        fprintf(out,"State %d lookahead %s %s\n", stateno,
                yyTokenName[iLookAhead],
                yycoverage[stateno][iLookAhead] ? "ok" : "missed");
      }
    }
  }
  return nMissed;
}
#endif
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  if( stateno>YY_MAX_SHIFT ) return stateno;
  assert( stateno <= YY_SHIFT_COUNT );
#if defined(YYCOVERAGE)
  yycoverage[stateno][iLookAhead] = 1;
#endif
  do{
    i = yy_shift_ofst[stateno];

    assert( iLookAhead!=YYNOCODE );

    i += iLookAhead;
    assert( i>=0 && i<sizeof(yy_lookahead)/sizeof(yy_lookahead[0]) );
    if( yy_lookahead[i]!=iLookAhead ){
#ifdef YYFALLBACK
      YYCODETYPE iFallback;            /* Fallback token */
      if( iLookAhead<sizeof(yyFallback)/sizeof(yyFallback[0])
             && (iFallback = yyFallback[iLookAhead])!=0 ){
#ifndef NDEBUG
        if( yyTraceFILE ){








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  if( stateno>YY_MAX_SHIFT ) return stateno;
  assert( stateno <= YY_SHIFT_COUNT );
#if defined(YYCOVERAGE)
  yycoverage[stateno][iLookAhead] = 1;
#endif
  do{
    i = yy_shift_ofst[stateno];
    assert( i>=0 && i+YYNTOKEN<=sizeof(yy_lookahead)/sizeof(yy_lookahead[0]) );
    assert( iLookAhead!=YYNOCODE );
    assert( iLookAhead < YYNTOKEN );
    i += iLookAhead;

    if( yy_lookahead[i]!=iLookAhead ){
#ifdef YYFALLBACK
      YYCODETYPE iFallback;            /* Fallback token */
      if( iLookAhead<sizeof(yyFallback)/sizeof(yyFallback[0])
             && (iFallback = yyFallback[iLookAhead])!=0 ){
#ifndef NDEBUG
        if( yyTraceFILE ){
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