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#define _GNU_SOURCE
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <errno.h>
#include <assert.h>
const char* USAGE =
"nman drvAttr [section|page] [page]\n"
"\n"
"Open man pages in a temporary nix-shell.\n"
"1 If one argument is given, the drvAttr & page have the same name.\n"
"2 If two arguments are given and the second arg is\n"
" a <number>) like 1, but in man section <number>\n"
" a <page> ) like 1, but open the page <page>\n"
"3 If three arguments are given, the order is <drvAttr> <sect> <page>\n";
void execNixShell(char const* drvAttr, int manSection, const char* manPage) {
assert(manSection >= -1);
char* manCmd;
// holy debug printf
//printf("attr: %s, sect: %d, page: %s\n", drvAttr, manSection, manPage);
int ret;
if (-1 == manSection) {
ret = asprintf(&manCmd, "man %s", manPage);
} else {
ret = asprintf(&manCmd, "man %d %s", manSection, manPage);
}
assert(ret != -1);
if (-1 == execlp("nix-shell", "nix-shell", "-p", drvAttr, "--run", manCmd, NULL)) {
fprintf(stderr, "%s\n", strerror(errno));
exit(-1);
}
free(manCmd);
}
int main(int argc, char** argv) {
int manSection = -1;
char* drvAttr;
char* manPage;
if (argc >= 3) {
// man section or -1 if no man section
int i = strtol(argv[2], NULL, 10);
if (i > 1) {
manSection = i;
}
}
// the first argument is always a derivation attribute
drvAttr = argv[1];
// nman does a convenient selection based on the number
// of attributes given, in order to do what the user means.
switch (argc) {
case 1:
fprintf(stderr, "%s", USAGE);
exit(-1);
break;
case 2:
// arg is package and drv attr
manPage = argv[1];
break;
case 3:
if (manSection == -1) {
// like 2:, but arg 2 is package
manPage = argv[2];
} else {
// man section given, page is arg 1
manPage = argv[1];
}
break;
case 4:
// arg 2 is manSection, arg 3 is package
manPage = argv[3];
break;
}
execNixShell(drvAttr, manSection, manPage);
}
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