1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
|
% -*- mode: Noweb; noweb-code-mode: c-mode -*-
\section{Using file modification dates}
\date{October 31, 1996}
This \texttt{noweb} filter
sets the date to the modification date of the file being woven.
It relies on the convention that
\begin{quote}
\verb+\date{+\emph{mumble}\verb+}+
\end{quote}
appears on a line by itself. \emph{Mumble} stands for any string.
The filter replaces \emph{Mumble} with the modifcation date and time
of the file as announced by \verb+@file+.
The filter uses POSIX functions, and it uses the \texttt{noweb} input
stuff, so it has to be linked with
\texttt{getline.o} \texttt{columns.o}, and \texttt{errors.o} from the
\texttt{noweb} distribution.
<<moddate.c*>>=
<<includes>>
<<local procs>>
main() {
char *s;
char *file = NULL;
while (s = getline(stdin))
if (match("@file ", s)) {
printf("%s", s);
file = get_file_name(s);
} else if (matches_date(s) && file != NULL)
print_modification_time(file);
else
printf("%s", s);
}
@
Matching ideas are stolen from Icon.
<<local procs>>=
match(char *pattern, char *s) {
return !strncmp(pattern, s, strlen(pattern));
}
<<local procs>>=
matches_date(char *s) {
return match("@text \\date{", s) && s[strlen(s)-2] == '}';
}
@
Allocate space for a file name and strip the trailing newline.
<<local procs>>=
char *get_file_name(char *s) {
char *p = (char *)malloc(strlen(s)); /* wastes some characters */
assert(p);
strcpy(p, s + strlen("@file "));
p[strlen(p)-1] = 0; /* trim newline */
return p;
}
@
To get a nicer format for the time, I would replace the call to
[[asctime]] with something else.
<<local procs>>=
void print_modification_time(char *file) {
struct stat buf;
int n = stat(file, &buf);
char *time;
if (n) {fprintf(stderr, "could not stat %s\n", file); exit(1); }
time = asctime(localtime(&buf.st_mtime));
if (time[strlen(time)-1] == '\n')
time[strlen(time)-1] = 0;
printf("@text \\date{%s}\\def\\today{%s}\n", time, time);
}
@
<<includes>>=
#include <time.h>
#include <stdlib.h>
#include <assert.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <string.h>
#include <stdio.h>
#include "getline.h"
|