3552

Stop requiring jump instructions to explicitly provide a ':label' type
for jump targets.

This has been a source of repeated confusion for my students:
  a) They'd add the ':label' to the label definition rather than the
  jump target (label use)
  b) They'd spend time thinking about whether the initial '+' prefix was
  part of the label name.

In the process I cleaned up a couple of things:

  - the space of names is more cleanly partitioned into labels and
    non-labels (clarifying that '_' and '-' are non-label prefixes)
  - you can't use label names as regular variables anymore
  - you can infer the type of a label just from its name

1 files changed, 1 insertions, 1 deletions

diff --git a/011load.cc b/011load.cc
index c129ba4b..5dd64335 100644
--- a/011load.cc
+++ b/011load.cc
@@ -178,7 +178,7 @@ string next_word(istream& in) {
 
 bool is_label_word(const string& word) {
   assert(!word.empty());
-  return !isalnum(word.at(0)) && word.at(0) != '$';
+  return !isalnum(word.at(0)) && string("$_-").find(word.at(0)) == string::npos;
 }
 
 bool ends_with(const string& s, const char c) {