make nutshell build

Makefile

@@ -84,8 +84,11 @@ lowercase: sysexits src/lowercase.c
 nonzero: src/nonzero.c
 	$(CC) $(CFLAGS) -o bin/nonzero src/nonzero.c
 
-nutshell: src/nutshell.c src/nutshell.h src/nutshell_builtins.c
-	$(CC) $(CFLAGS) -o bin/nutshell src/nutshell.c
+nutshell.o: libio usefulmacros src/nutshell.c src/nutshell.h src/nutshell_builtins.c
+	$(CC) $(CFLAGS) -c -o build/nutshell.o src/nutshell.c
+
+nutshell: libio nutshell.o
+	$(CC) $(CFLAGS) -o bin/nutshell build/libio.o build/nutshell.o
 
 roll.o: lib/libio.h src/roll.c sysexits
 	$(CC) $(CFLAGS) -c -o build/roll.o src/roll.c

src/nutshell.c

@@ -1,26 +1,17 @@
+#include <ctype.h> /* isspace(3) */
+#include <stddef.h> /* NULL */
+#include <stdio.h> /* getc(3) */
+#include <stdlib.h> /* getenv(3), rand(3), srand(3) */
+#include <string.h> /* strcmp(3) */
+#include <sys/wait.h> /* wait(2) */
+#include <time.h> /* time(3) */
+#include <unistd.h> /* fork(2), write(2) */
+#include "libio.h"
+#include "usefulmacros.h"
+
 #include "nutshell.h"
 #include "nutshell_builtins.c"
 
-int
-fdputd(int fd, int d){
-	if(d < 0){
-		putc('-', stdout);
-		d *= -1;
-	}
-	return printf("%d\n", d);
-}
-
-/* Probably not buggy. */
-int
-fdputs(int fd, char *s){
-	int r;
-
-	r = write(1, s, strlen(s));
-	r += write(1, "\n", 1);
-
-	return r;
-}
-
 static int
 parse_argv(char *buffer, char **argv, int argc_max){
 	int i;
@@ -82,9 +73,8 @@ run(char *buf){
 	argc = parse_argv(buf, argv, ARRAYLEN(argv));
 
 	/* builtins get priority */
-	for(i = 0; i < ARRAYLEN(builtins); ++i)
-		if(strcmp(builtins[i].name, argv[0]) == 0)
-			return builtins[i].f(argc, argv);
+	if((i = isbuiltin(argv[0])) != 0)
+		return builtins[i - 1].f(argc, argv);
 
 	if(state.jailed)
 		goto runerr;
@@ -96,8 +86,8 @@ runerr:
 
 int main(int argc, char *argv[]){
 	static char buf[BUF_MAX];
+	static char prompt[] = DEFAULT_PROMPT;
 
-	srand(time(NULL));
 	builtin_init(0, empty_argv);
 
 	for(;;){

src/nutshell.h

@@ -1,41 +1,10 @@
-#include <ctype.h> /*
-	isspace(3)
-*/
-#include <stddef.h> /*
-	NULL
-*/
-#include <stdio.h> /*
-	getc(3)
-*/
-#include <stdlib.h> /*
-	getenv(3)
-	rand(3)
-	srand(3)
-*/
-#include <string.h> /*
-	strcmp(3)
-	strlen(3)
-*/
-#include <sys/wait.h> /*
-	wait(2)
-*/
-#include <time.h> /*
-	time(3)
-*/
-#include <unistd.h> /*
-	fork(2)
-	write(2)
-*/
-
-#define ARRAYLEN(a) sizeof(a) / sizeof(*(a))
-
 /* conservative defaults */
 #define ARGV_MAX 10
 #define BUF_MAX 100
 
+#define DEFAULT_PROMPT "^_^?: "
+
 char *empty_argv[1] = { NULL };
-char *nethack_name = "nethack";
-char prompt[] = "^_^?: ";
 
 struct {
 	int jailed;
@@ -44,6 +13,3 @@ struct {
 	0,
 	0
 };
-
-int fdputd(int fd, int d);
-int fdputs(int fd, char *s);

src/nutshell_builtins.c

@@ -1,3 +1,6 @@
+#define NETHACK_NAME "nethack"
+
+int builtin_builtin	(int, char **);
 int builtin_escape	(int, char **);
 int builtin_init	(int, char **);
 int builtin_jail	(int, char **);
@@ -9,13 +12,44 @@ struct {
 	char *name;
 	int (*f)(int, char **);
 }builtins[] = {
-	{"escape", builtin_escape},
+	/* guaranteed to exist */
+	{"builtin", builtin_builtin},
 	{"init", builtin_init},
+
+	/* optional additions */
+	{"escape", builtin_escape},
 	{"jail", builtin_jail},
 	{"nethack", builtin_nethack},
 	{"status", builtin_status}
 };
 
+int
+isbuiltin(char *s){
+	int i;
+
+	for(i = 0; i < ARRAYLEN(builtins); ++i)
+		if(strcmp(builtins[i].name, s) == 0)
+			return i + 1;
+	return 0;
+}
+
+int
+builtin_builtin(int argc, char **argv){
+	int i;
+
+	if(argc < 2){
+		fdputs(2, "%s: needs argument(s)");
+		return 1;
+	}
+
+	++argv;
+
+	while(*argv != NULL)
+		if(!isbuiltin(*argv))
+			return 1;
+	return 0;
+}
+
 int
 builtin_escape(int argc, char **argv){
 	char *s;
@@ -32,11 +66,7 @@ builtin_escape(int argc, char **argv){
 
 int
 builtin_init(int argc, char **argv){
-	fdputs(1,"\
-\
-	A voice whispers to you. \"Play NetHack...\" (\"nethack\" [enter]).\n\
-	What would you like to do?"
-	);
+	srand(time(NULL));
 	return 0;
 }
 
@@ -54,7 +84,9 @@ builtin_jail(int argc, char **argv){
 
 int
 builtin_nethack(int argc, char **argv){
+	static char *nethack_name = NETHACK_NAME;
 	char *a[2];
+
 	if(fork() == 0){
 		a[0] = nethack_name;
 		a[1] = NULL;