2.11BSD#431 - /usr/ingres/source/equel/operator.c

   1: #
   2: # include   <stdio.h>
   3: 
   4: # include   "constants.h"
   5: # include   "globals.h"
   6: 
   7: /*
   8: **  OPERATOR -- process a token starting with an operator
   9: **
  10: **	Processes operators, strings, comments, and
  11: **	floating constants without a leading 0.
  12: **
  13: **	Parameters:
  14: **		chr - first character of token {Cmap [chr] == OPATR}
  15: **
  16: **	Returns:
  17: **		NUMBER or STRING token, or operator token.
  18: **		CONTINUE on error.
  19: **
  20: **	Side Effects:
  21: **		Adds a node to the Symbol space, and returns adress
  22: **		in "yylval".
  23: **		Opcode is set to the opcode of the operator.
  24: **		May backup a character.
  25: **
  26: **	Defines:
  27: **		operator()
  28: **
  29: **	Requires:
  30: **		yylval - to return a value for the token
  31: **		Cmap - to get character classes
  32: **		Opcode - to return opcodes for operators
  33: **		Token - for the lex codes of begin comments, and string
  34: **		        quotes.
  35: **		Optab - to search through for operators.
  36: **		backup() - to push a char back on the input stream
  37: **		getch() - to get a char from the input stream
  38: **		number() - to process mantissas
  39: **		sequal() - for string equality tests
  40: **		string() - for processing strings
  41: **		comment() - "      "      comments
  42: **		addsym() - to add a node to symbol space
  43: **		yysemerr() - to report illegal operators
  44: **		CONTINUE - to have yylex() get next token on error
  45: **
  46: **	Called By:
  47: **		yylex()
  48: **
  49: **	Files:
  50: **		globals.h
  51: **
  52: **	Diagnostics:
  53: **		"bad operator" - an operator was read and not found
  54: **				 The operator is per force one character,
  55: **				 and is skipped.
  56: **
  57: **	History:
  58: **		written - 4/19/78 (marc)
  59: **
  60: */
  61: 
  62: operator(chr)
  63: char    chr;
  64: {
  65:     register struct optab   *op;
  66:     char            opbuf [3];
  67: 
  68:     opbuf [0] = chr;
  69:     opbuf [1] = getch();
  70:     opbuf [2] = '\0';
  71: 
  72:     if (opbuf [0] == '.' && Cmap [opbuf [1]] == NUMBR)
  73:     {
  74:         /* floating mantissa w/o leading 0 */
  75:         backup(opbuf [1]);
  76:         return (number(opbuf [0]));
  77:     }
  78:     if (Cmap [opbuf [1]] != OPATR)
  79:     {
  80:         backup(opbuf [1]);
  81:         opbuf [1] = '\0';
  82:     }
  83:     /* operator has been reduced to its smallest
  84: 	 * possible length, now try to find it in the
  85: 	 * operator table [tokens.y]
  86: 	 */
  87:     for ( ; ; )
  88:     {
  89:         for (op = Optab; op->op_term; op++)
  90:             if (sequal(op->op_term, opbuf))
  91:                 break;
  92:         if (!op->op_term && opbuf [1])
  93:         {
  94:             /* reduce a 2 char operator to 1 char,
  95: 			 * and re-search
  96: 			 */
  97:             backup(opbuf[1]);
  98:             opbuf [1] = '\0';
  99:             continue;
 100:         }
 101:         break;
 102:     }
 103:     if (op->op_term)
 104:     {
 105:         /* string quotes ? */
 106:         if (op->op_token == Tokens.sp_quote)
 107:             return (string(op));
 108: 
 109:         /* comment indicator ? */
 110:         if (op->op_token == Tokens.sp_bgncmnt)
 111:             return (comment());
 112: 
 113:         /* {sequal(opbuf, op->op_term)} */
 114:         Opcode = op->op_code;
 115:         yylval = addsym(op->op_term);
 116:         return (op->op_token);
 117:     }
 118:     yysemerr("bad operator", opbuf);
 119: 
 120:     /* operator not found, skip token and try again */
 121:     return (CONTINUE);
 122: }

Defined functions