pkgs/profpatsch: add nman

2 files changed, 92 insertions, 0 deletions

diff --git a/pkgs/profpatsch/nman/default.nix b/pkgs/profpatsch/nman/default.nix
new file mode 100644
index 00000000..10e5417f
--- /dev/null
+++ b/pkgs/profpatsch/nman/default.nix
@@ -0,0 +1,12 @@
+{ lib, runCommandCC }:
+
+runCommandCC "nman" {
+  meta = with lib; {
+    description = "Invoke manpage in temporary nix-shell";
+    license = licenses.gpl3;
+  };
+} ''
+    cc -o nman ${./nman.c}
+    install -D nman $out/bin/nman
+''
+
diff --git a/pkgs/profpatsch/nman/nman.c b/pkgs/profpatsch/nman/nman.c
new file mode 100644
index 00000000..0e02ff3e
--- /dev/null
+++ b/pkgs/profpatsch/nman/nman.c
@@ -0,0 +1,80 @@
+#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);
+}