Listing 3. yacc Interpretation Code
1: %{
2: /* err = do_arithmetic (struct LOGFILE *,
char * arithmetic_string)
3: This yacc program is designed to perform
simple arithmetic on vectors, contained
4: (optionally) in multiple levels of
5: parentheses.
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20: "do_arithmetic" returns:
21: 0 - normal processing completed
22: 1 - yyparse internal syntactical error
23: 2 - unpaired parentheses
24: 3 - more than 1 '=' sign
25: 4 - unrecognized curve name
27: Written by D. A. Provins, February, 1994
28: */
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35: #define MAGIC 999 /* used to indicate a
temporary vector */
36: #define STACKSIZE 200 /* value MUST be <
MAGIC */
37: #define STRING_LEN 90 /* maximum length of
string describing arithmetic */
38: #define max(a,b) ((a) < (b) ? (a) : (b))
39: int DeBuG = 0; /* do_arithmetic sets if
environment "las_debug" set */
40: int las_nocase = 0; /* do_arithmetic sets
if "las_nocase" valued */
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68: static double * temp = NULL, /* "holding"
vector */
69: * vec1 = NULL, /* one of 2
containing real digits */
70: * vec2 = NULL,
71: * tmp [STACKSIZE]; /* stacked
temporary vectors */
72: %}
73: %token INTEGER FLOAT DOUBLE NUMBER VARIABLE\
EQUAL LPAREN
74: %token RPAREN PLUS MINUS TIMES DIVIDE RAISE \
LHS
75: %left PLUS, MINUS
76: %left TIMES, DIVIDE
77: %left RAISE
78: %%
79: equation:
80: lhs EQUAL expr {
81: pop (&code, &value);
82: get_curve (temp, code);
83: if (DeBuG) {
84: printf (
"variable = expression equation\
recognized\\n");
85: if (!code)
86: printf ("Final scalar = <%f>\\n",
value);
87: else {
88: printf ("Final vector:\\n");
89: for (i = 0; i < num_digits; i++)
90: printf (" %f\\n", temp [i]);
91: }
92: printf ("Final vector name: <%s>\\n", label);
94: while (stkptr)
95: pop (&code, &value);
96: }
97: }
98: | expr {
99: pop (&code, &value); /* is this
required?? */
100: get_curve (temp, code);
101: if (DeBuG) {
102: printf (
"non-replacement equation recognized\\n");
103:
104: if (!code)
105: printf ("Final scalar = <%f>\\n", value);
106: else {
107: printf ("Final vector:\\n");
108: for (i = 0; i < num_digits; i++)
109: printf (" %f\\n", temp [i]);
110: }
111: printf ("Final vector name: <%s>\\n", label);
113: while (stkptr)
114: pop (&code, &value);
115: }
116: }
117: ;
118: lhs :
119: LHS {
120: if ((code = which_curve \
(yytext, curves)) == 0)
121: return 4; /* unrecognized curve
name */
122: strcpy (label, yytext);
123: j = push (code, value);
124: if (DeBuG) {
125: printf ("code <%d> is lhs \
<%s>\\n", code, yytext);
126: }
127: }
128: expr :
129: NUMBER {
130: code = 0; /* scalar value */
131: j = push (code, value);
132: }
133: | VARIABLE {
134: if ((code = which_curve \
(yytext, curves)) == 0)
135: return 4; /* unrecognized curve
name */
136: j = push (code, value);
137: if (DeBuG)
138: printf ("code <%d> is vector\
<%s>\\n", code, yytext);
139: }
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426: %%
427: /**********************do_arithmetic************************/
428: int
429: do_arithmetic (
430: #ifdef _NO_PROTO
431: LogFile, arithmetic_string)
432: struct LOG_FILE * LogFile;
433: char * arithmetic_string;
434: #else
435: struct LOG_FILE * LogFile;
char * arithmetic_string);
436: #endif
437: {
438: int i, j;
439: char * str = NULL;
440: extern char * my_arithmetic_pointer,
441: * current_pointer,
442: * end_of_string_pointer;
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475: /* Ensure the parentheses match
476: */
477: for (i = j = 0; i < strlen (my_arithmetic_string); i++)
478: if (my_arithmetic_string [i] == '(')
479: j++;
480: else if (my_arithmetic_string [i] == ')')
481: j--;
482: if (j)
483: return 2; /* unpaired parentheses detected */
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493: current_pointer =
494: & my_arithmetic_string [0];
495: end_of_string_pointer =
496: & my_arithmetic_string [strlen \
(my_arithmetic_string)];
497: /* Determine the unknown's name, and
do case switch if needed */
499: for (i = j = 0; i < strlen \
(my_arithmetic_string); i++)
500: if (my_arithmetic_string [i] == '=')
501: j++;
502: else
503: if (las_nocase)
504: my_arithmetic_string [i] =
505: (char) toupper ((int) \
my_arithmetic_string [i]);
506: if (j > 1)
507: return 3; /* more than one '=' */
508: if (j) {
509: strncpy (label, my_arithmetic_string, \
max(j, STRING_LEN - 1));
510: label [j] = '\\0';
511: }
512: /* Get the # of curves, # of digits and the
curve names. Add two additional
513: pointers to the curves array:
514: 1 - NULL, or UNKNOWN (in case its needed)
515: 2 - NULL terminator (for searching the
516: array */
517: num_curves = LogFile -> num_curves;
518: num_digits = LogFile -> data_points;
519: null_value = LogFile -> WellInfo.null;
520: curves = (char **) malloc (sizeof (char *) *\
(num_curves + 2));
521: for (i = 0; i < num_curves; i++)
522: curves [i] = LogFile -> \
Curve [i].curve_name;
523: curves [num_curves + 0] = NULL;
524: curves [num_curves + 1] = NULL;
525: /* If we don't recognize the name,
then we'll add it to the
526: list, otherwise, ignore it. */
528: if ((i = which_curve (label, curves)) == 0)
529: curves [num_curves + 0] = label;
530: do_initialization (); /* assign space */
531: LogFileAddress = LogFile; /* get_digits
needs this address */
532: err = yyparse (); /* parse the statement;
do the work */
533: restart_lex (); /* ensure we can do
another arithmetic run */
534: /* err = 0: processing completed normally
535: 1: yyparse internal syntactical error
536: 2: unpaired parentheses
537: 3: more than 1 equal sign
538: 4: unrecognized curve n
539: */
540: return err;
541: }
---------------lines deleted------------
557: /***************push*********************/
558: int
559: push (
560: #ifdef _NO_PROTO
561: code, value)
562: int code; float value;
563: #else
564: int code, float value)
565: #endif
566: /* This routine "pushes" a code, and
optionally a value onto a stack.
569: code = 0: a scalar value, as a float is to
be added to the stack
570: code = 1+: the "code" indicates
which curve is referenced and is to
571: be added to the stack
572: int push (int code, float value)
573: */
574: {
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613: }
614: /**************pop************************/
615: int
616: pop (
617: #ifdef _NO_PROTO
618: code, value)
619: int * code; float * value;
620: #else
621: int * code, float * value)
622: #endif
623: /* This routine "pops" a code,
and optionally a value from the stack.
626: code = 0: a scalar value, as a float was
removed from the stack the
627: value and code are returned
628: code = 1+: the "code" indicates
which curve is referenced and
629: was removed from the stack
630: int pop (int * code, float * value)
631: */
632: {
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658: }
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