[bug #65763] strictly compare strings in macro packages

[G. Branden Robinson]

Update of bug #65763 (group groff):

                 Summary: Do actual string comparisons in macro packages =>
strictly compare strings in macro packages

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Follow-up Comment #1:

I suspect this may be low priority, perhaps so low that it's not worth doing,
because _as deployed_, all of _groff_'s full-service macro packages are
prepared to format documents using the basic Latin character set.

I'm also still a bit undecided whether we should have a syntactically sweeter
way of doing string comparisons.

Here's a proof of concept I did back when discussing this issue with Deri.

It's pretty simple.  It grabs the symbol '~' for use as an operator in a
conditional expression and then uses the same infrastructure that's already in
place to handle `\?`.


$ git stash show -p 1
diff --git a/src/roff/troff/input.cpp b/src/roff/troff/input.cpp
index 8d828a01e..7288f31c5 100644
--- a/src/roff/troff/input.cpp
+++ b/src/roff/troff/input.cpp
@@ -6002,6 +6002,25 @@ static bool do_if_request()
     }
     result = is_abstract_style(nm);
   }
+  else if (c == '~') {
+    tok.next();
+    symbol nm1 = get_name(true /* required */);
+    symbol nm2 = get_name(true /* required */);
+    if ((nm1.is_null() || nm2.is_null())) {
+      skip_branch();
+      return false;
+    }
+    macro *rm1 = static_cast<macro *>(request_dictionary.lookup(nm1));
+    macro *rm2 = static_cast<macro *>(request_dictionary.lookup(nm2));
+    macro *m1 = rm1->to_macro();
+    macro *m2 = rm2->to_macro();
+    if ((0 /* nullptr */ == m1) || (0 /* nullptr */ == m2)) {
+      error("cannot perform equality comparison on a request");
+      skip_branch();
+      return false;
+    }
+    result = (*m1 == *m2);
+  }
   else if (tok.is_space())
     result = false;
   else if (tok.is_usable_as_delimiter()) {


Not sure what the best way forward is.  I suggest that nothing about it is a
priority for 1.24.


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