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      1 # Clarify the flex debug trace by substituting first line of each rule.
      2 # Francois Pinard <pinard (at] iro.umontreal.ca>, July 1990.
      3 #
      4 # Rewritten to process correctly \n's in scanner input.
      5 # BEGIN section modified to correct a collection of rules.
      6 # Michal Jaegermann <michal (at] phys.ualberta.ca>, December 1993
      7 #
      8 # Sample usage:
      9 #	flex -d PROGRAM.l
     10 #	gcc -o PROGRAM PROGRAM.c -lfl
     11 #	PROGRAM 2>&1 | gawk -f debflex.awk PROGRAM.l
     12 #
     13 # (VP's note: this script presently does not work with either "old" or
     14 #  "new" awk; fixes so it does will be welcome)
     15 
     16 BEGIN {
     17     # Insure proper usage.
     18 
     19     if (ARGC != 2) {
     20 	print "usage: gawk -f debflex.awk FLEX_SOURCE <DEBUG_OUTPUT";
     21 	exit (1);
     22     }
     23 
     24     # Remove and save the name of flex source.
     25 
     26     source = ARGV[1];
     27     ARGC--;
     28 
     29     # Swallow the flex source file.
     30 
     31     line = 0;
     32     section = 1;
     33     while (getline <source) {
     34 
     35 	# Count the lines.
     36 
     37 	line++;
     38 
     39 	# Count the sections.  When encountering section 3,
     40 	# break out of the awk BEGIN block.
     41 
     42 	if (match ($0, /^%%/)) {
     43 	    section++;
     44 	    if (section == 3) {
     45 		break;
     46 	    }
     47 	}
     48 	else {
     49 	    # Only the lines in section 2 which do not begin in a
     50 	    # tab or space might be referred to by the flex debug
     51 	    # trace.  Save only those lines.
     52 
     53 	    if (section == 2 && match ($0, /^[^ \t]/)) {
     54 		rules[line] = $0;
     55 	    }
     56 	}
     57     }
     58     dashes = "-----------------------------------------------------------";
     59     collect = "";
     60     line = 0;
     61 }
     62 
     63 # collect complete rule output from a scanner
     64 $0 !~ /^--/ {
     65     collect = collect "\n" $0;
     66     next;
     67 }
     68 # otherwise we have a new rule - process what we got so far
     69 {
     70     process();
     71 }
     72 # and the same thing if we hit EOF
     73 END {
     74     process();
     75 }
     76 
     77 function process() {
     78 
     79     # splitting this way we loose some double dashes and
     80     # left parentheses from echoed input - a small price to pay
     81     n = split(collect, field, "\n--|[(]");
     82 
     83     # this loop kicks in only when we already collected something
     84     for (i = 1; i <= n; i++) {
     85 	if (0 != line) {
     86 	    # we do not care for traces of newlines.
     87 	    if (0 == match(field[i], /\"\n+\"[)]/)) {
     88 		if (rules[line]) {
     89 		    text = field[i];
     90 		    while ( ++i <= n) {
     91 			text = text field[i];
     92 		    }
     93 		    printf("%s:%d: %-8s -- %s\n",
     94 			   source, line, text, rules[line]);
     95 		}
     96 		else {
     97 		    print;
     98 		    printf "%s:%d: *** No such rule.\n", source, line;
     99 		}
    100 	    }
    101 	    line = 0;
    102 	    break;
    103 	}
    104 	if ("" != field[i]) {
    105 	    if ("end of buffer or a NUL)" == field[i]) {
    106 		print dashes;  # Simplify trace of buffer reloads
    107 		continue;
    108 	    }
    109 	    if (match(field[i], /accepting rule at line /)) {
    110 		# force interpretation of line as a number
    111 		line = 0 + substr(field[i], RLENGTH);
    112 		continue;
    113 	    }
    114 	    # echo everything else
    115 	    printf("--%s\n", field[i]);
    116 	}
    117     }
    118     collect = "\n" $0;  # ... and start next trace
    119 }
    120