Add #i"pathname" syntax for reading values from modular input files.

reader.c

@@ -34,6 +34,8 @@ static value_t read_weak_box(reader_state_t *state);
 static value_t read_definition(reader_state_t *state);
 static value_t read_placeholder(reader_state_t *state);
 
+static value_t read_indirect(value_t path);
+
 static void next_char(reader_state_t *state);
 static void skip_whitespace(reader_state_t *state);
 
@@ -155,6 +157,10 @@ static value_t read_special(reader_state_t *state)
     return read_definition(state);
   case '=':
     return read_placeholder(state);
+  case 'I':
+  case 'i':
+    next_char(state);
+    return read_indirect(read_string(state));
   default:
     release_assert(NOTREACHED("Invalid character in special value."));
     return UNDEFINED;
@@ -432,6 +438,7 @@ static value_t read_string(reader_state_t *state)
   value_t value;
 
   release_assert(buffer != NULL);
+  release_assert(state->ch == '"');
 
   next_char(state);
 
@@ -666,6 +673,19 @@ static value_t read_placeholder(reader_state_t *state)
   }
 }
 
+static value_t read_indirect(value_t path)
+{
+  char *name = value_to_string(path);
+  FILE *f = fopen(name, "r");
+  value_t v;
+  free(name);
+
+  release_assert(f != NULL);
+  v = read_value(f);
+  fclose(f);
+  return v;
+}
+
 static bool is_placeholder(reader_state_t *state, value_t value)
 {
   for (value_t item = state->ref_alist.value; !is_nil(item); item = _CDDR(item))

rosella.c

@@ -207,15 +207,9 @@ static void test_reader(void)
     fflush(stdout);
 
     v = read_value(stdin);
-    if (is_struct(v) && _get_struct(v)->type == lookup_builtin(BI_LAMBDA))
-    {
-      print_value(run_interpreter(v, NIL));
-    }
-    else
-    {
-      print_value(v);
-    }
-    nl(); nl();
+
+    print_value(v); nl();
+    nl();
   } while (v != NIL);
 }