tb Allow empty lines

ulib/string/char.h

@@ -14,4 +14,17 @@
 #define string_chr_isascii(c) (!((c) < 0 || (c) > 0x7f))
 #define string_chr_isxdigit(c) (((c) >= '0' && (c) <= '9') || ((c) >= 'a' && (c) <= 'f') || ((c) >= 'A' && (c) <= 'F'))
 
+#define STRING_CHECK_ALL(str, macro, okp) \
+  do { \
+    (okp) = true; \
+    char *__p = (str); \
+    while (*__p) { \
+      if (!macro(*__p)) { \
+        (okp) = false; \
+        break; \
+      } \
+      __p++; \
+    } \
+  } while(0)
+
 #endif // ULIB_STRING_CHAR_H_

user/tb/interp.c

@@ -167,6 +167,13 @@ bool interp_runstring(char *string, InterpResult **res, bool logcmds, bool inter
       uprintf("+%s\n", line);
     }
 
+    bool skip;
+    STRING_CHECK_ALL(line, string_chr_isspace, skip);
+    if (skip) {
+      line = string_tokenizealloc(NULL, "\n");
+      continue;
+    }
+
     Tokenizer tz; ZERO(&tz);
     tz_init(&tz, line);