1 #LyX 2.0 created this file. For more info see http://www.lyx.org/
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48 \paragraph_separation indent
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64 LyX and Literate Programming
65 \begin_inset Newline newline
73 \begin_inset Newline newline
76 edmar-w-jr@technologist.com
80 \begin_layout Plain Layout
81 Modified by Bernard Michael Hurley bernardh@westherts.ac.uk ---- Don't blame
82 Edmar for any errors that have crept in!
90 \begin_layout Abstract
95 This example program is provided for educational use only.
96 The functionality in this C program has been superceded by the equivalent
99 examples/listerrors.lyx
101 which should be installed in the LyX scripts directory.
108 \begin_layout Plain Layout
120 \begin_layout Standard
121 \begin_inset CommandInset toc
122 LatexCommand tableofcontents
129 \begin_layout Section
133 \begin_layout Standard
134 After typesetting a document, LyX scans the LaTeX log file looking for errors.
135 For each error found, the line number is obtained and a error box is displayed
136 in the LyX screen at that position.
139 \begin_layout Standard
140 To use this feature to view compilation errors while working with literate
141 documents, we need a program that filters the compilation errors and puts
142 them in a format suitable for LyX reading it.
146 \begin_layout Standard
147 In this document we present a filter that recognizes compilation error messages
148 from noweb, gnu C, and the IBM C compiler (xlc).
151 \begin_layout Standard
152 The filter is required to read from standard input, parse for error messages
153 and copy the error messages to the standard output.
154 During the output process, the filter must present the error messages in
155 a format that LyX can interpret, currently, the LaTeX error message format.
156 Of course, nothing will prevent future LyX releases from being able to
157 read other formats as well (like gcc error messages for example).
158 This mechanism is necessary to fully explore the literate programming tool's
162 \begin_layout Section
175 main (int argc, char **argv)
187 switch (argv[1][0]) {
195 <<Scan input for noweb error messages>>
207 <<Scan input for xlc error messages>>
219 <<AIX system using both noweb and xlc>>
235 <<Solaris and Linux systems using both noweb and gcc>>
251 <<Scan input for gcc error messages>>
267 <<Scan input for gcc error messages>>
283 <<Function prototypes>>=
287 int main (int argc, char **argv);
294 \begin_layout Section
298 \begin_layout Standard
299 We resort to some global variables to allow access from several different
301 These are the buffer and related pointers used during the parse of the
306 <<Global variables>>=
310 char buffer[200][200];
311 \begin_inset Newline newline
315 \begin_inset Newline newline
319 \begin_inset Newline newline
323 \begin_inset Newline newline
329 \begin_layout Section
333 \begin_layout Standard
334 The output format mimics the TeX error messages format.
335 This function prints a number of lines residing in the global variable
340 , a program name and line number.
341 There is no special requirement on the input strings, they can be anything.
345 \begin_layout Plain Layout
346 This function has been slightly changed from EW's original to make scanning
347 a bit easier with LaTeX::scanLogFile().
348 The test has been added because LyX can crash if empty lines are allowed
349 here --- I can't figure out why! --- BMH
366 output_error (int buf_size, int error_line, char *tool)
382 fprintf(stdout, "! Build Error: ==> %s ==>
388 fprintf(stdout, " ...
402 for (i=0; i<buf_size; i++)
406 if (strlen(buffer[i]) != 0)
410 fprintf(stdout, "%s", buffer[i]);
432 <<Function prototypes>>=
436 void output_error (int buf_size, int error_line, char *tool);
443 \begin_layout Section
444 Functions Implementation
447 \begin_layout Standard
448 Both noweave and notangle routines, always output one single line for each
449 error found, thus to scan the buffer for noweb error messages is enough
450 to exam one input line at a time.
451 Note that the noweb software does not provide a line error number, so all
452 errors boxes related to noweb messages will be displayed at the beginning
457 <<Scan input for noweb error messages>>=
469 while (fgets(buffer[0], 200, stdin)) {
477 output_error(1, err_line, "noweb");
492 \begin_layout Standard
493 The examination itself is very inefficient.
494 Unfortunately noweb doesn't have any characteristic that would help to
495 identify one of its error messages.
496 The solution is to collect all possible output messages in an array of
497 strings, and turn the examination process into a linear search in this
506 <<Global variables>>=
510 char *noweb_msgs[] = {
514 "couldn't open file",
518 "couldn't open temporary file",
522 "error writing temporary file",
534 "Bad format sequence",
538 "Can't open output file",
542 "Can't open temporary file",
546 "Capacity exceeded:",
550 "Ignoring unknown option -",
554 "This can't happen:",
558 "non-numeric line number in"
570 char *noweb_msgs_mimic_gcc[] = {
574 ": unescaped << in documentation chunk"
585 \begin_layout Standard
586 A noweb error message can be any string that contains a matching pair of
599 > >, or any of the above strings
608 \begin_inset Newline newline
612 \begin_inset Newline newline
615 noweb_try (int buf_line)
616 \begin_inset Newline newline
620 \begin_inset Newline newline
624 \begin_inset Newline newline
628 \begin_inset Newline newline
632 \begin_inset Newline newline
635 b = buffer[buf_line];
636 \begin_inset Newline newline
640 \begin_inset Newline newline
644 \begin_inset Newline newline
647 for (i=0; i<1; i++) {
648 \begin_inset Newline newline
651 s = (char *)strstr (b, noweb_msgs_mimic_gcc[i]);
652 \begin_inset Newline newline
656 \begin_inset Newline newline
659 t = (char *)strchr(buffer[buf_line], ':');
660 \begin_inset Newline newline
663 err_line = atoi(t+1);
664 \begin_inset Newline newline
667 t = buffer[buf_line];
668 \begin_inset Newline newline
672 \begin_inset Newline newline
675 while (*(t++) = *(s++));
676 \begin_inset Newline newline
680 \begin_inset Newline newline
684 \begin_inset Newline newline
688 \begin_inset Newline newline
691 s = (char *)strstr(b, "<<");
692 \begin_inset Newline newline
696 \begin_inset Newline newline
699 s = (char *)strstr(s+2, ">>");
700 \begin_inset Newline newline
704 \begin_inset Newline newline
708 \begin_inset Newline newline
712 \begin_inset Newline newline
716 \begin_inset Newline newline
719 for (i = 0; i < 12; ++i) {
720 \begin_inset Newline newline
723 s = (char *)strstr (b, noweb_msgs[i]);
724 \begin_inset Newline newline
728 \begin_inset Newline newline
732 \begin_inset Newline newline
736 \begin_inset Newline newline
740 \begin_inset Newline newline
744 \begin_inset Newline newline
748 \begin_inset Newline newline
752 \begin_inset Newline newline
759 <<Function prototypes>>=
763 int noweb_try (int buf_line);
770 \begin_layout Standard
771 The xlc compiler always outputs one single line for each error found, thus
772 to scan the buffer for xlc error messages it is enough to exam one input
777 <<Scan input for xlc error messages>>=
789 while (fgets(buffer[last_buf_line], 200, stdin)) {
797 output_error(1, err_line, "xlc");
812 \begin_layout Standard
813 A xlc error message is easy to identify.
814 Every error message starts with a quoted string with no spaces, a comma,
816 \begin_inset Quotes eld
820 \begin_inset Quotes erd
823 , a space, and some variable text.
824 The following routine tests if a given buffer line matches this criteria:
844 xlc_try (int buf_line)
860 t = buffer[buf_line];
868 while (*s != '"' && *s != ' ' && *s != '
878 if (*t != '"' || *s != '"' || strncmp(s+1, ", line ", 7) != 0)
906 <<Function prototypes>>=
910 int xlc_try (int buf_line);
917 \begin_layout Standard
918 The gcc compiler error messages are more complicated to scan.
919 Each error can span more than one line in the buffer.
920 The good news is that every buffer line on each error has the same pattern,
921 and share the same line number.
922 Thus the strategy will be to accumulate lines in the buffer while the reported
923 line number is still the same.
924 At the time they differ, all the accumulated lines, except the last one,
925 will belong to one single error message, which now can be output-ed to
929 \begin_layout Standard
930 Every gcc error message contains a string with no space followed by a
931 \begin_inset Quotes eld
935 \begin_inset Quotes eld
939 If the next character is a space, then this line is a header of a error
940 message and the next line will detail the line number of the source code
941 where the error was found.
942 Otherwise, the next thing is a integer number followed by another
943 \begin_inset Quotes eld
947 \begin_inset Quotes eld
954 <<Scan input for gcc error messages>>=
974 while (fgets(buffer[last_buf_line], 200, stdin)) {
978 /****** Skip lines until I find an error */
982 s = (char *)strpbrk(buffer[last_buf_line], " :");
986 if (s == NULL || *s == ' ')
990 continue; /* No gcc error found here */
998 <<gcc error message criteria is to find a "...:999:" or a "...: ">>
1002 /****** OK It is an error message, get line number */
1006 err_line = atoi(s+1);
1010 if (last_err_line == 0 || last_err_line == err_line) {
1014 last_err_line = err_line;
1018 continue; /* It's either a header or a continuation, don't output
1027 /****** Completed the scan of one error message, output it to LyX
1032 discharge_buffer(1);
1040 } while (fgets(buffer[last_buf_line], 200, stdin));
1048 /****** EOF completes the scan of whatever was being scanned */
1052 discharge_buffer(0);
1064 <<gcc error message criteria is to find a "...:999:" or a "...: ">>=
1068 /****** Search first ":" in the error number */
1072 s = (char *)strpbrk(buffer[last_buf_line], " :");
1080 if (s == NULL || *s == ' ')
1084 <<No gcc error found here, but it might terminate the scanning of a previous
1089 /****** Search second ":" in the error number */
1093 t = (char *)strpbrk(s+1, " :");
1094 \begin_inset Newline newline
1097 if (t == NULL || *t == ' ')
1098 \begin_inset Newline newline
1101 <<No gcc error found here, but it might terminate the scanning of a previous
1103 \begin_inset Newline newline
1106 /****** Verify if is all digits between ":" */
1107 \begin_inset Newline newline
1110 if (t != s+1+strspn(s+1, "0123456789"))
1111 \begin_inset Newline newline
1114 <<No gcc error found here, but it might terminate the scanning of a previous
1116 \begin_inset Newline newline
1131 <<No gcc error found here, but it might terminate the scanning of a previous
1144 discharge_buffer(1);
1159 \begin_layout Standard
1160 As we mentioned, when the scan of one gcc error message is completed everything
1161 in the buffer except the last line is one single error message.
1162 But if the scan terminates with a EOF or through finding one line that
1163 does not match the gcc error message criteria, then there is no
1164 \begin_inset Quotes eld
1168 \begin_inset Quotes erd
1171 in the buffer to be concerned with.
1172 In those cases we empty the buffer completely.
1184 <<Function bodies>>=
1192 discharge_buffer (int save_last)
1200 if (last_err_line != 0) {
1204 clean_gcc_messages();
1208 if (save_last != 0) {
1212 output_error(last_buf_line-1, last_err_line, "gcc");
1216 strcpy (buffer[0], buffer[last_buf_line-1]);
1220 last_err_line = err_line;
1236 clean_gcc_messages();
1240 output_error(last_buf_line-1, last_err_line, "gcc");
1268 <<Function prototypes>>=
1272 void discharge_buffer (int save_last);
1279 \begin_layout Standard
1281 \begin_inset Quotes eld
1285 \begin_inset Quotes erd
1288 superfluous information from gcc messages, namely the name of the noweb
1289 file and the line number of the Error.
1293 \begin_layout Plain Layout
1295 For instance, some way of distinguishing between gcc Errors and Warnings
1305 <<Function bodies>>=
1313 clean_gcc_messages ()
1333 int search_len = sprintf(search, ".nw:%d:", last_err_line);
1341 for (index = 0; index < last_buf_line-1; index++) {
1345 tail = (char *)strstr (buffer[index], search);
1349 if ( tail == NULL) {
1353 tail = (char *) strstr (buffer[index], ".nw:");
1385 head = buffer[index];
1389 while (*(head++) = *(tail++));
1409 <<Function prototypes>>=
1413 void clean_gcc_messages ();
1420 \begin_layout Standard
1421 To combine the scan of noweb error messages and xlc error messages is very
1423 We just try each one for every input line:
1427 <<AIX system using both noweb and xlc>>=
1436 \begin_inset Newline newline
1439 while (fgets(buffer[0], 200, stdin)) {
1440 \begin_inset Newline newline
1444 \begin_inset Newline newline
1447 output_error(1, err_line, "noweb");
1448 \begin_inset Newline newline
1451 else if (xlc_try(0))
1452 \begin_inset Newline newline
1455 output_error(1, err_line, "xlc");
1456 \begin_inset Newline newline
1460 \begin_inset Newline newline
1464 \begin_inset Newline newline
1470 \begin_layout Standard
1471 To combine the scan of noweb error messages and gcc error messages is simple
1472 if we realize that it is not possible to find a noweb error message in
1473 the middle of a gcc error message.
1474 So we just repeat the gcc procedure and test for noweb error messages in
1475 the beginning of the scan:
1479 <<Solaris and Linux systems using both noweb and gcc>>=
1499 while (fgets(buffer[last_buf_line], 200, stdin)) {
1503 /****** Skip lines until I find an error */
1507 if (last_buf_line == 0 && noweb_try(0)) {
1511 output_error(1, err_line, "noweb");
1523 s = (char *)strpbrk(buffer[last_buf_line], " :");
1527 if (s == NULL || *s == ' ')
1531 continue; /* No gcc error found here */
1539 <<gcc error message criteria is to find a "...:999:" or a "...: ">>
1543 /****** OK It is an error, get line number */
1547 err_line = atoi(s+1);
1551 if (last_err_line == 0 || last_err_line == err_line) {
1555 last_err_line = err_line;
1559 continue; /* It's either a header or a continuation, don't output
1568 /****** Completed the scan of one error message, output it to LyX
1573 discharge_buffer(1);
1581 } while (fgets(buffer[last_buf_line], 200, stdin));
1589 /****** EOF completes the scan of whatever was being scanned */
1593 discharge_buffer(0);
1604 \begin_layout Section
1605 Wrapping the code into a file
1617 #include <strings.h>
1625 <<Global variables>>
1629 <<Function prototypes>>
1640 \begin_layout Standard
1641 To build this program, we want to add the
1642 \begin_inset Quotes eld
1646 \begin_inset Quotes erd
1649 option in the tangle command to force gdb to load the file
1658 In accordance with this, we pass the
1659 \begin_inset Quotes eld
1663 \begin_inset Quotes erd
1678 if [ -z "$NOWEB_SOURCE" ]; then NOWEB_SOURCE=Literate.nw; fi
1682 notangle -L -Rlisterrors.c ${NOWEB_SOURCE} > listerrors.c
1686 gcc -g -o listerrors listerrors.c
1693 \begin_layout Standard
1694 This project can be tangled and compiled from LyX if you set
1700 to call a generic script that always extracts a scrap named
1705 Here is a example of such generic script:
1708 \begin_layout LyX-Code
1710 \begin_inset Newline newline
1713 notangle -Rbuild-script $1 | env NOWEB_SOURCE=$1 sh
1716 \begin_layout LyX-Code