Redesign new environment variables to use env_var_t instead of wcstring

Migrate uses of empty() to missing() to distinguish between empty variable and unset variable

1 files changed, 6 insertions, 0 deletions

diff --git a/env.h b/env.h
index 435cf22a..691aaf74 100644
--- a/env.h
+++ b/env.h
@@ -106,6 +106,12 @@ public:
     bool missing(void) const { return is_missing; }
     bool missing_or_empty(void) const { return missing() || empty(); }
     const wchar_t *c_str(void) const;
+    env_var_t &operator=(const env_var_t &s) {
+        is_missing = s.is_missing;
+        wcstring::operator=(s);
+        return *this;
+    }
+
 };
 /**
  Gets the variable with the specified name, or an empty string if it does not exist.