astlib.c

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}

SORAST *
#ifdef __USE_PROTOS
ast_cut_between(SORAST *a, SORAST *b)
#else
ast_cut_between(a, b)
SORAST *a,*b;
#endif
{
  SORAST *end, *ret;
  require(a!=NULL&&b!=NULL, "ast_cut_between: NULL input tree");
  /* find node pointing to b */
  for (end=a; end->ast_right!=NULL&&end->ast_right!=b; end=end->ast_right)
    {;}
  require(end->ast_right!=NULL, "ast_cut_between: a,b not connected");
  end->ast_right = NULL;  /* don't want it point to 'b' anymore */
  ret = a->ast_right;
  a->ast_right = b;
  return ret;
}

SList *
#ifdef __USE_PROTOS
ast_to_slist(SORAST *t)
#else
ast_to_slist(t)
SORAST *t;
#endif
{
  SList *list=NULL;
  SORAST *p;

  for (p=t; p!=NULL; p=p->ast_right)
  {
    slist_add(&list, p);
  }
  return list;
}

SORAST *
#ifdef __USE_PROTOS
slist_to_ast(SList *list)
#else
slist_to_ast(list)
SList *list;
#endif
{
  SORAST *t=NULL, *last=NULL;
  SList *p;

  for (p = list->next; p!=NULL; p=p->next)
  {
    SORAST *u = (SORAST *)p->elem;
    if ( last==NULL ) last = t = u;
    else { last->ast_right = u; last = u; }
  }
  return t;
}

void
#ifdef __USE_PROTOS
ast_free(SORAST *t)
#else
ast_free(t)
SORAST *t;
#endif
{
    if ( t == NULL ) return;
    ast_free( t->ast_down );
    ast_free( t->ast_right );
    free( t );
}

int
#ifdef __USE_PROTOS
ast_nsiblings(SORAST *t)
#else
ast_nsiblings(t)
SORAST *t;
#endif
{
  int n=0;

  while ( t!=NULL )
  {
    n++;
    t = t->ast_right;
  }
  return n;
}

SORAST *
#ifdef __USE_PROTOS
ast_sibling_index(SORAST *t, int i)
#else
ast_sibling_index(t,i)
SORAST *t;
int i;
#endif
{
  int j=1;
  require(i>0, "ast_sibling_index: i<=0");

  while ( t!=NULL )
  {
    if ( j==i ) return t;
    j++;
    t = t->ast_right;
  }
  return NULL;
}

static void
#ifdef __USE_PROTOS
scanast_free(ScanAST *t)
#else
scanast_free(t)
ScanAST *t;
#endif
{
    if ( t == NULL ) return;
    scanast_free( t->down );
    scanast_free( t->right );
    free( t );
}

/*
 * ast_scan
 *
 * This function is like scanf(): it attempts to match a template
 * against an input tree.  A variable number of tree pointers
 * may be set according to the '%i' labels in the template string.
 * For example:
 *
 *   ast_scan("#( 6 #(5 %1:4 %2:3) #(1 %3:3 %4:3) )",
 *            t, &w, &x, &y, &z);
 *
 * Naturally, you'd want this converted from
 *
 *   ast_scan("#( RangeOp #(Minus %1:IConst %2:Var) #(Plus %3:Var %4Var) )",
 *        t, &w, &x, &y, &z);
 *
 * by SORCERER.
 *
 * This function call must be done withing a SORCERER file because SORCERER
 * must convert the token references to the associated token number.
 *
 * This functions parses the template and creates trees which are then
 * matched against the input tree.  The labels are set as they are
 * encountered; hence, partial matches may leave some pointers set
 * and some NULL.  This routines initializes all argument pointers to NULL
 * at the beginning.
 *
 * This function returns the number of labels matched.
 */
int
#ifdef PCCTS_USE_STDARG
ast_scan(char *templ, SORAST *tree, ...)
#else
ast_scan(va_alist)
va_dcl
#endif
{
  va_list ap;
  ScanAST *t;
  int n, i, found=0;
  SORAST ***label_ptrs=NULL;

#ifdef PCCTS_USE_STDARG
  va_start(ap, tree);
#else
  char *templ;
  SORAST *tree;

  va_start(ap);
  templ = va_arg(ap, char *);
  tree = va_arg(ap, SORAST *);
#endif

  /* make a ScanAST tree out of the template */
  t = stringparser_parse_scanast(templ, &n);

  /* make an array out of the labels */
  if ( n>0 )
  {
    label_ptrs = (SORAST ***) calloc(n, sizeof(SORAST **));
    require(label_ptrs!=NULL, "ast_scan: out of memory");
    for (i=1; i<=n; i++)
    {
      label_ptrs[i-1] = va_arg(ap, SORAST **);
      *(label_ptrs[i-1]) = NULL;
    }
  }

  /* match the input tree against the template */
  ast_scanmatch(t, tree, label_ptrs, &found);

  scanast_free(t);
  free(label_ptrs);

  return found;
}

static ScanAST *
#ifdef __USE_PROTOS
new_scanast(int tok)
#else
new_scanast(tok)
int tok;
#endif
{
    ScanAST *p = (ScanAST *) calloc(1, sizeof(ScanAST));
    if ( p == NULL ) {fprintf(stderr, "out of mem\n"); exit(-1);}
  p->token = tok;
  return p;
}

static ScanAST *
#ifdef __USE_PROTOS
stringparser_parse_scanast(char *templ, int *num_labels)
#else
stringparser_parse_scanast(templ, num_labels)
char *templ;
int *num_labels;
#endif
{
  StringLexer lex;
  StringParser parser;
  ScanAST *t;

  stringlexer_init(&lex, templ);
  stringparser_init(&parser, &lex);
  t = stringparser_parse_tree(&parser);
  *num_labels = parser.num_labels;
  return t;
}

static void
#ifdef __USE_PROTOS
stringparser_match(StringParser *parser, int token)
#else
stringparser_match(parser, token)
StringParser *parser;
int token;
#endif
{
  if ( parser->token != token ) sorcerer_panic("bad tree in ast_scan()");
}

/*
 * Match a tree of the form:
 *    (root child1 child2 ... childn)
 * or,
 *    node
 *
 * where the elements are integers or labeled integers.
 */
static ScanAST *
#ifdef __USE_PROTOS
stringparser_parse_tree(StringParser *parser)
#else
stringparser_parse_tree(parser)
StringParser *parser;
#endif
{
  ScanAST *t=NULL, *root, *child, *last = NULL;

  if ( parser->token != POUND )
  {
    return stringparser_parse_element(parser);
  }
  stringparser_match(parser,POUND);
  parser->token = stringscan_gettok(parser->lexer);
  stringparser_match(parser,LPAREN);
  parser->token = stringscan_gettok(parser->lexer);
  root = stringparser_parse_element(parser);
  while ( parser->token != RPAREN )
  {
    child = stringparser_parse_element(parser);
    if ( t==NULL ) { t = child; last = t; }
    else { last->right = child; last = child; }
  }
  stringparser_match(parser,RPAREN);
  parser->token = stringscan_gettok(parser->lexer);
  root->down = t;
  return root;
}

static ScanAST *
#ifdef __USE_PROTOS
stringparser_parse_element(StringParser *parser)
#else
stringparser_parse_element(parser)
StringParser *parser;
#endif
{
  static char ebuf[100];
  int label = 0;

  if ( parser->token == POUND )
  {
    return stringparser_parse_tree(parser);
  }
  if ( parser->token == PERCENT )
  {
    parser->token = stringscan_gettok(parser->lexer);
    stringparser_match(parser,INT);
    label = atoi(parser->lexer->text);
    parser->num_labels++;
    if ( label==0 ) sorcerer_panic("%%0 is an invalid label");
    parser->token = stringscan_gettok(parser->lexer);
    stringparser_match(parser,COLON);
    parser->token = stringscan_gettok(parser->lexer);
    /* can label tokens and wildcards */
    if ( parser->token != INT && parser->token != PERIOD )
      sorcerer_panic("can only label tokens");
  }
  if ( parser->token == INT )
  {
    ScanAST *p = new_scanast(atoi(parser->lexer->text));
    parser->token = stringscan_gettok(parser->lexer);
    p->label_num = label;
    return p;
  }
  if ( parser->token == PERIOD )
  {
    ScanAST *p = new_scanast(0);  /* token of 0 is wildcard */
    parser->token = stringscan_gettok(parser->lexer);
    p->label_num = label;
    return p;
  }
  sprintf(ebuf, "mismatch token in ast_scan(): %s", scan_token_str(parser->token));
  sorcerer_panic(ebuf);
    return NULL; /* MR20 make -Wall happy */
}

static void
#ifdef __USE_PROTOS
stringparser_init(StringParser *parser, StringLexer *input)
#else
stringparser_init(parser, input)
StringParser *parser;
StringLexer *input;
#endif
{
  parser->lexer = input;
  parser->token = stringscan_gettok(parser->lexer);
  parser->num_labels = 0;
}

static void
#ifdef __USE_PROTOS
stringlexer_init(StringLexer *scanner, char *input)
#else
stringlexer_init(scanner, input)
StringLexer *scanner;
char *input;
#endif
{
  scanner->text[0]='\0';
  scanner->input = input;
  scanner->p = input;
  stringscan_advance(scanner);
}

static void
#ifdef __USE_PROTOS
stringscan_advance(StringLexer *scanner)
#else
stringscan_advance(scanner)
StringLexer *scanner;
#endif
{
  if ( *(scanner->p) == '\0' ) scanner->c = StringScanEOF;
  scanner->c = *(scanner->p)++;
}

static int
#ifdef __USE_PROTOS
stringscan_gettok(StringLexer *scanner)
#else
stringscan_gettok(scanner)
StringLexer *scanner;
#endif
{
  char *index = &scanner->text[0];
  static char ebuf[100];

  while ( isspace(scanner->c) ) { stringscan_advance(scanner); }
  if ( isdigit(scanner->c) )
  {
    int tok = INT;
    while ( isdigit(scanner->c) ) {
      *index++ = scanner->c;
      stringscan_advance(scanner);
    }
    *index = '\0';
    return tok;
  }
  switch ( scanner->c )
  {
    case '#' : stringscan_advance(scanner); return POUND;
    case '(' : stringscan_advance(scanner); return LPAREN;
    case ')' : stringscan_advance(scanner); return RPAREN;
    case '%' : stringscan_advance(scanner); return PERCENT;
    case ':' : stringscan_advance(scanner); return COLON;
    case '.' : stringscan_advance(scanner); return PERIOD;
    case '\0' : return StringScanEOF;
    case StringScanEOF : return StringScanEOF;
    default  :
      sprintf(ebuf, "invalid char in ast_scan: '%c'", scanner->c);
      sorcerer_panic(ebuf);
            return 0; /* MR20 Make -Wall happy */
  }
}