take input file on command line including - for stdin

src/passbook.c

@@ -365,7 +365,7 @@ void node_save(const node_t *p, FILE *f){
 int save_levelorder(const node_t *p, const char * filename){
   FILE *f = fopen(filename,"w");
   if (f == NULL){
-    debug_printf("Couldn't open file %s for writing.\n",filename);
+    fprintf(stderr,"Couldn't open file %s for writing.\n",filename);
     return -1;
   }
   nodeptr_list_t lst = {.head = NULL, .last = NULL};
@@ -450,6 +450,8 @@ static int execute(void){
   return 0;
 }
 
+/* returns >=0 on success, in which case the number of instructions executed
+   is returned. Returns < 0 on failure. */
 static int run(FILE *f){
   debug_printf("Attempting to read program. max line length: %d\n",MAX_LINE_LENGTH);
 
@@ -492,7 +494,7 @@ static int run(FILE *f){
     instructionCount++;
     int r = execute();
     if (r != 0){
-      return r;
+      return -1;
     }
   }
 
@@ -528,7 +530,7 @@ static int run(FILE *f){
 }
 
 
-int main(void){
+int main(const int argc, const char * argv[]){
   cred_t cred1, cred2;
   cred1.password = "asdfa";
   cred1.username = "user1";
@@ -544,6 +546,32 @@ int main(void){
   p = put(p,"http://blah.com",cred2);
   assert(strcmp(lookup(p,"http://blah.com")->cred.username,cred2.username) == 0);
 
-  run(stdin);
+  if (argc <= 1){
+    fprintf(stderr,"Usage: %s file1 file2 ...\n",argv[0]);
+    fprintf(stderr,"       use - to read from standard input\n");
+    exit(0);
+  }
+  
+  for (int i = 1; i<argc; i++){
+    FILE *f;
+    if (strcmp(argv[i],"-") == 0){
+      f = stdin;
+    }else{
+      f = fopen(argv[i],"r");
+      if (f == NULL){
+        fprintf(stderr,"Error opening %s for reading\n",argv[i]);
+        exit(1);
+      }
+    }
+    int ans = run(f);
+    if (ans < 0){
+      fprintf(stderr,"Error\n");
+      exit(1);
+    }
+    /* do not close stdin */
+    if (f != stdin){
+      fclose(f);
+    }
+  }
   return 0;
 }