pdutils/sqlparser.c at master · mooseman/pdutils · GitHub

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/*  sqlparser.c  */


/*
 *      SQL parser. performs a recursive descent parse
 *      to evaluate an expression permissible
 *      within the following grammar:
 *
 *      expr    :       stmt SEMI
 *      stmt    :       select from ( where )
 *      select  :       SELECT ( STAR | field_list )
 *      star    :       *
 *      field_list  :   field_name ( COMMA field_name )
 *      field_name  :   identifier
 *      from        :   FROM table_name
 *      table_name  :   identifier
 *      where_stmt  :   WHERE ( cond_stmt )
 *      cond_stmt   :   value OP value ( AND | OR cond_stmt )
 *      value       :   field_name | int | string
 *      semi        :   ;
 *
 */


/*   #include "sql.h"    */


char *nxtch;     /* Parser scan pointer */


/*
 *  macros:
 *  ungetch - Put back the last character examined.
 *  getch   - return the next character from expr string.
*/

#define ungetch()   nxtch--
#define getch()     *nxtch++


int expr(char *expbuf)
{


}


/* stmt : select from ( where ) */
int stmt()
{


}


/* select : SELECT ( STAR | field_list )  */
int select()
{


}


/* star :  *  */
int star()
{


}


int field_list()
{


}


int field_name()
{


}


int from()
{


}


int table_name()
{


}


int where_stmt()
{


}


int cond_stmt()
{


}


int value()
{


}


int semi()
{


}


int main(int argc, char *argv[]) {
  if (argc < 2) error(usage);
  if (*argv[1] == '-') { debug = 1; --argc; ++argv; }
  if (argc < 2) error(usage);
  openinfile(argv[1]);
  init();
  if (!PROGRAM()) error("Syntax error");
  fclose(inf);

  return 0;

}