y_tab.c

编译原理实验

		/*
		** we have a new state - find out what to do
		*/
	yy_newstate:
		if ( ( yy_n = yypact[ yy_state ] ) <= YYFLAG )
			goto yydefault;         /* simple state */
#if YYDEBUG
		/*
		** if debugging, need to mark whether new token grabbed
		*/
		yytmp = yychar < 0;
#endif
		if ( ( yychar < 0 ) && ( ( yychar = yylex() ) < 0 ) )
			yychar = 0;             /* reached EOF */
#if YYDEBUG
		if ( yydebug && yytmp )
		{
			register int yy_i;

			fprintf(file, "Received token " );
			if ( yychar == 0 )
				fprintf(file, "end-of-file\n" );
			else if ( yychar < 0 )
				fprintf(file, "-none-\n" );
			else
			{
				for ( yy_i = 0; yytoks[yy_i].t_val >= 0;
					yy_i++ )
				{
					if ( yytoks[yy_i].t_val == yychar )
						break;
				}
				fprintf(file, "%s\n", yytoks[yy_i].t_name );
			}
		}
#endif /* YYDEBUG */
		if ( ( ( yy_n += yychar ) < 0 ) || ( yy_n >= YYLAST ) )
			goto yydefault;
		if ( yychk[ yy_n = yyact[ yy_n ] ] == yychar )  /*valid shift*/
		{
			yychar = -1;
			yyval = yylval;
			yy_state = yy_n;
			if ( yyerrflag > 0 )
				yyerrflag--;
			goto yy_stack;
		}

	yydefault:
		if ( ( yy_n = yydef[ yy_state ] ) == -2 )
		{
#if YYDEBUG
			yytmp = yychar < 0;
#endif
			if ( ( yychar < 0 ) && ( ( yychar = yylex() ) < 0 ) )
				yychar = 0;             /* reached EOF */
#if YYDEBUG
			if ( yydebug && yytmp )
			{
				register int yy_i;

				fprintf(file, "Received token " );
				if ( yychar == 0 )
					fprintf(file, "end-of-file\n" );
				else if ( yychar < 0 )
					fprintf(file, "-none-\n" );
				else
				{
					for ( yy_i = 0;
						yytoks[yy_i].t_val >= 0;
						yy_i++ )
					{
						if ( yytoks[yy_i].t_val
							== yychar )
						{
							break;
						}
					}
					fprintf(file, "%s\n", yytoks[yy_i].t_name );
				}
			}
#endif /* YYDEBUG */
			/*
			** look through exception table
			*/
			{
				register int *yyxi = yyexca;

				while ( ( *yyxi != -1 ) ||
					( yyxi[1] != yy_state ) )
				{
					yyxi += 2;
				}
				while ( ( *(yyxi += 2) >= 0 ) &&
					( *yyxi != yychar ) )
					;
				if ( ( yy_n = yyxi[1] ) < 0 )
					YYACCEPT;
			}
		}

		/*
		** check for syntax error
		*/
		if ( yy_n == 0 )        /* have an error */
		{
			/* no worry about speed here! */
			switch ( yyerrflag )
			{
			case 0:         /* new error */
				yyerror( "syntax error" );
				goto skip_init;
			yyerrlab:
				/*
				** get globals into registers.
				** we have a user generated syntax type error
				*/
				yy_pv = yypv;
				yy_ps = yyps;
				yy_state = yystate;
				yynerrs++;
			skip_init:
			case 1:
			case 2:         /* incompletely recovered error */
					/* try again... */
				yyerrflag = 3;
				/*
				** find state where "error" is a legal
				** shift action
				*/
				while ( yy_ps >= yys )
				{
					yy_n = yypact[ *yy_ps ] + YYERRCODE;
					if ( yy_n >= 0 && yy_n < YYLAST &&
						yychk[yyact[yy_n]] == YYERRCODE)                                        {
						/*
						** simulate shift of "error"
						*/
						yy_state = yyact[ yy_n ];
						goto yy_stack;
					}
					/*
					** current state has no shift on
					** "error", pop stack
					*/
#if YYDEBUG
#       define _POP_ "Error recovery pops state %d, uncovers state %d\n"
					if ( yydebug )
						fprintf(file, _POP_, *yy_ps,
							yy_ps[-1] );
#       undef _POP_
#endif
					yy_ps--;
					yy_pv--;
				}
				/*
				** there is no state on stack with "error" as
				** a valid shift.  give up.
				*/
				YYABORT;
			case 3:         /* no shift yet; eat a token */
#if YYDEBUG
				/*
				** if debugging, look up token in list of
				** pairs.  0 and negative shouldn't occur,
				** but since timing doesn't matter when
				** debugging, it doesn't hurt to leave the
				** tests here.
				*/
				if ( yydebug )
				{
					register int yy_i;

					fprintf(file, "Error recovery discards " );
					if ( yychar == 0 )
						fprintf(file, "token end-of-file\n" );
					else if ( yychar < 0 )
						fprintf(file, "token -none-\n" );
					else
					{
						for ( yy_i = 0;
							yytoks[yy_i].t_val >= 0;
							yy_i++ )
						{
							if ( yytoks[yy_i].t_val
								== yychar )
							{
								break;
							}
						}
						fprintf(file, "token %s\n",
							yytoks[yy_i].t_name );
					}
				}
#endif /* YYDEBUG */
				if ( yychar == 0 )      /* reached EOF. quit */
					YYABORT;
				yychar = -1;
				goto yy_newstate;
			}
		}/* end if ( yy_n == 0 ) */
		/*
		** reduction by production yy_n
		** put stack tops, etc. so things right after switch
		*/
#if YYDEBUG
		/*
		** if debugging, print the string that is the user's
		** specification of the reduction which is just about
		** to be done.
		*/
		if ( yydebug )
			fprintf(file, "Reduce by (%d) \"%s\"\n",
				yy_n, yyreds[ yy_n ] );
#endif
		yytmp = yy_n;                   /* value to switch over */
		yypvt = yy_pv;                  /* $vars top of value stack */
		/*
		** Look in goto table for next state
		** Sorry about using yy_state here as temporary
		** register variable, but why not, if it works...
		** If yyr2[ yy_n ] doesn't have the low order bit
		** set, then there is no action to be done for
		** this reduction.  So, no saving & unsaving of
		** registers done.  The only difference between the
		** code just after the if and the body of the if is
		** the goto yy_stack in the body.  This way the test
		** can be made before the choice of what to do is needed.
		*/
		{
			/* length of production doubled with extra bit */
			register int yy_len = yyr2[ yy_n ];

			if ( !( yy_len & 01 ) )
			{
				yy_len >>= 1;
				yyval = ( yy_pv -= yy_len )[1]; /* $$ = $1 */
				yy_state = yypgo[ yy_n = yyr1[ yy_n ] ] +
					*( yy_ps -= yy_len ) + 1;
				if ( yy_state >= YYLAST ||
					yychk[ yy_state =
					yyact[ yy_state ] ] != -yy_n )
				{
					yy_state = yyact[ yypgo[ yy_n ] ];
				}
				goto yy_stack;
			}
			yy_len >>= 1;
			yyval = ( yy_pv -= yy_len )[1]; /* $$ = $1 */
			yy_state = yypgo[ yy_n = yyr1[ yy_n ] ] +
				*( yy_ps -= yy_len ) + 1;
			if ( yy_state >= YYLAST ||
				yychk[ yy_state = yyact[ yy_state ] ] != -yy_n )
			{
				yy_state = yyact[ yypgo[ yy_n ] ];
			}
		}
					/* save until reenter driver code */
		yystate = yy_state;
		yyps = yy_ps;
		yypv = yy_pv;
	}
	/*
	** code supplied by user is placed in this switch
	*/
	switch( yytmp )
	{
case 3:	/* Statement : FOR T FROM Expr TO Expr STEP Expr DRAW L_BRACKET Expr COMMA Expr R_BRACKET */
# line 31 "funcdraw.y"
{  	start = GetExprValue(yypvt[-10]);
				end	  = GetExprValue(yypvt[-8]);
				step  = GetExprValue(yypvt[-6]);
				DrawLoop(start, end, step, yypvt[-3], yypvt[-1]) ;
			} break;
case 4:	/* Statement : ORIGIN IS L_BRACKET Expr COMMA Expr R_BRACKET */
# line 37 "funcdraw.y"
{ 	Origin_x = GetExprValue(yypvt[-3]); 
				Origin_y = GetExprValue(yypvt[-1]); 
			} break;
case 5:	/* Statement : SCALE IS L_BRACKET Expr COMMA Expr R_BRACKET */
# line 41 "funcdraw.y"
{	Scale_x = GetExprValue(yypvt[-3]); 
				Scale_y = GetExprValue(yypvt[-1]); 
			} break;
case 6:	/* Statement : ROT IS Expr */
# line 45 "funcdraw.y"
{	Rot_angle = GetExprValue(yypvt[-0]);  
			} break;
case 7:	/* Expr : T */
# line 49 "funcdraw.y"
{ yyval = MakeExprNode(T); } break;
case 8:	/* Expr : CONST_ID */
# line 50 "funcdraw.y"
{ yyval = MakeExprNode(CONST_ID,  tokens.value); } break;
case 9:	/* Expr : Expr PLUS Expr */
# line 51 "funcdraw.y"
{ yyval = MakeExprNode(PLUS,  yypvt[-2], yypvt[-0]); } break;
case 10:	/* Expr : Expr MINUS Expr */
# line 52 "funcdraw.y"
{ yyval = MakeExprNode(MINUS, yypvt[-2], yypvt[-0]); } break;
case 11:	/* Expr : Expr MUL Expr */
# line 53 "funcdraw.y"
{ yyval = MakeExprNode(MUL,   yypvt[-2], yypvt[-0]); } break;
case 12:	/* Expr : Expr DIV Expr */
# line 54 "funcdraw.y"
{ yyval = MakeExprNode(DIV,   yypvt[-2], yypvt[-0]); } break;
case 13:	/* Expr : Expr POWER Expr */
# line 55 "funcdraw.y"
{ yyval = MakeExprNode(POWER, yypvt[-2], yypvt[-0]); } break;
case 14:	/* Expr : L_BRACKET Expr R_BRACKET */
# line 56 "funcdraw.y"
{ yyval = yypvt[-1]; } break;
case 15:	/* Expr : PLUS Expr */
# line 57 "funcdraw.y"
{ yyval = yypvt[-0]; } break;
case 16:	/* Expr : MINUS Expr */
# line 59 "funcdraw.y"
{ yyval = MakeExprNode(MINUS, MakeExprNode(CONST_ID, 0.0), yypvt[-0]); } break;
case 17:	/* Expr : FUNC L_BRACKET Expr R_BRACKET */
# line 60 "funcdraw.y"
{ yyval = MakeExprNode(FUNC, tokens.FuncPtr, yypvt[-1]);} break;
case 18:	/* Expr : ERRTOKEN */
# line 61 "funcdraw.y"
{ yyerror("error token in the input");} break;

	}
	goto yystack;           /* reset registers in driver code */
}
# ifndef YY_ADVANCE_ERROR_HOLD_NOT_USED
yyinsert (token,value)
	int token;
	YYSTYPE value;
{
		int yyn;

		if ( ( yyn = yypact[ *yyps ] ) <= YYFLAG )
			return 0 ;
		if ( ( ( yyn += token ) < 0 ) || ( yyn >= YYLAST ) )
			return 0 ;
		if ( yychk[ yyn = yyact[ yyn ] ] != token )
			return 0 ;
		yystate = yyn;
		if ( ++yyps >= &yys[ YYMAXDEPTH ] )
		{
			yyerror( "yacc stack overflow" );
			return 0 ;
		}
		*yyps = yystate;
		*++yypv = value;
		return 1 ;
}

int yyexpect (int token)
{ 
	while (yychar && yychar != (token)) 
		if ((yychar = yylex()) <=0) 
			yychar = 0;
	return yychar != 0;
}
# endif