Add support for target visibility, use for dist, test, install

This means we can no longer write:

install = false

Now it should be:

*: install = false

15 files changed, 73 insertions, 36 deletions

diff --git a/build/root.build b/build/root.build
index fd751bc..730200b 100644
--- a/build/root.build
+++ b/build/root.build
@@ -13,7 +13,6 @@ cxx{*}: extension = cxx
 
 cxx.poptions =+ -I$out_root -I$src_root
 
-# All exe{} in tests/ are, well, tests. Don't install them.
+# All exe{} in tests/ are, well, tests.
 #
 tests/exe{*}: test = true
-tests/: install = false
diff --git a/build2/bin/init.cxx b/build2/bin/init.cxx
index 5a13a87..59d9ce6 100644
--- a/build2/bin/init.cxx
+++ b/build2/bin/init.cxx
@@ -83,7 +83,6 @@ namespace build2
         v.insert<string>    ("bin.exe.suffix");
 
         v.insert<map<string, string>> ("bin.lib.version",
-                                       false,
                                        variable_visibility::project);
       }
 
@@ -202,7 +201,7 @@ namespace build2
 
           if (v == nullptr)
             fail (loc) << "unable to determine binutils target" <<
-              info << "consider specifying it with " << var.name <<
+              info << "consider specifying it with " << var <<
               info << "or first load a module that can provide it as a hint, "
                        << "such as c or cxx";
 
diff --git a/build2/c/init.cxx b/build2/c/init.cxx
index 7d104b0..503d942 100644
--- a/build2/c/init.cxx
+++ b/build2/c/init.cxx
@@ -159,7 +159,7 @@ namespace build2
         v["cc.type"],
         v["cc.system"],
 
-        v.insert<string>   ("c.std", false, variable_visibility::project),
+        v.insert<string>   ("c.std", variable_visibility::project),
 
         v.insert<string>   ("c.id"),
         v.insert<string>   ("c.id.type"),
diff --git a/build2/config/operation.cxx b/build2/config/operation.cxx
index e6ab14a..78c63b1 100644
--- a/build2/config/operation.cxx
+++ b/build2/config/operation.cxx
@@ -187,7 +187,7 @@ namespace build2
               // something is broken.
               //
               if (r == nullptr)
-                fail (loc) << "inherited variable " << var.name << " value "
+                fail (loc) << "inherited variable " << var << " value "
                            << "is not from a root scope";
 
               // If none of the outer project's configurations use this value,
@@ -198,7 +198,7 @@ namespace build2
               {
                 diag_record dr;
                 dr << warn (loc) << "saving previously inherited variable "
-                   << var.name;
+                   << var;
 
                 dr << info (loc) << "because project " << r->out_path ()
                    << " no longer uses it in its configuration";
diff --git a/build2/context.cxx b/build2/context.cxx
index a3678dd..1c50610 100644
--- a/build2/context.cxx
+++ b/build2/context.cxx
@@ -235,7 +235,7 @@ namespace build2
       //
       v.insert ("subprojects");
 
-      v.insert<string> ("extension", false, variable_visibility::project);
+      v.insert<string> ("extension", variable_visibility::target);
     }
 
     gs.assign<dir_path> ("build.work") = work;
diff --git a/build2/cxx/init.cxx b/build2/cxx/init.cxx
index 9aa30dc..de52b47 100644
--- a/build2/cxx/init.cxx
+++ b/build2/cxx/init.cxx
@@ -159,7 +159,7 @@ namespace build2
         v["cc.type"],
         v["cc.system"],
 
-        v.insert<string>   ("cxx.std", false, variable_visibility::project),
+        v.insert<string>   ("cxx.std", variable_visibility::project),
 
         v.insert<string>   ("cxx.id"),
         v.insert<string>   ("cxx.id.type"),
diff --git a/build2/dist/init.cxx b/build2/dist/init.cxx
index 338f6c8..2bf26e0 100644
--- a/build2/dist/init.cxx
+++ b/build2/dist/init.cxx
@@ -49,8 +49,11 @@ namespace build2
         v.insert<path>         ("dist.cmd");
         v.insert<strings>      ("dist.archives");
 
-        v.insert<bool>         ("dist");         // Flag.
-        v.insert<string>       ("dist.package"); // Project's package name.
+        v.insert<bool> ("dist", variable_visibility::target); // Flag.
+
+        // Project's package name.
+        //
+        v.insert<string> ("dist.package", variable_visibility::project);
       }
     }
 
diff --git a/build2/dump.cxx b/build2/dump.cxx
index 506ebff..9c26235 100644
--- a/build2/dump.cxx
+++ b/build2/dump.cxx
@@ -74,7 +74,7 @@ namespace build2
       const value& v (p.second);
       assert (v.type == nullptr);
 
-      os << var.name << (v.extra == 1 ? " =+ " : " += ");
+      os << var << (v.extra == 1 ? " =+ " : " += ");
       dump_value (os, v, false);
     }
     else
@@ -86,7 +86,7 @@ namespace build2
       if (var.type != nullptr)
         os << '[' << var.type->name << "] ";
 
-      os << var.name << " = ";
+      os << var << " = ";
 
       // If this variable is overriden, print both the override and the
       // original values.
diff --git a/build2/install/init.cxx b/build2/install/init.cxx
index f91e9dc..73e4c1e 100644
--- a/build2/install/init.cxx
+++ b/build2/install/init.cxx
@@ -189,10 +189,9 @@ namespace build2
         // way we distinguish between the two is via the presence/absence of
         // the trailing directory separator.
         //
-        v.insert<path>   ("install", false, variable_visibility::project);
-        v.insert<string> ("install.mode", false, variable_visibility::project);
-        v.insert<bool>   ("install.subdirs", false,
-                          variable_visibility::project);
+        v.insert<path>   ("install",         variable_visibility::target);
+        v.insert<string> ("install.mode",    variable_visibility::project);
+        v.insert<bool>   ("install.subdirs", variable_visibility::project);
       }
 
       // Register our alias and file rules.
diff --git a/build2/module.cxx b/build2/module.cxx
index e1e8afd..432c595 100644
--- a/build2/module.cxx
+++ b/build2/module.cxx
@@ -101,10 +101,8 @@ namespace build2
             i->second.init (rs, bs, loc, i->second.module, f, opt, hints));
 
     const variable& lv (var_pool.insert<bool> (name + ".loaded",
-                                               false,
                                                variable_visibility::project));
     const variable& cv (var_pool.insert<bool> (name + ".configured",
-                                               false,
                                                variable_visibility::project));
     bs.assign (lv) = l;
     bs.assign (cv) = c;
diff --git a/build2/parser.cxx b/build2/parser.cxx
index 689db66..1bc3519 100644
--- a/build2/parser.cxx
+++ b/build2/parser.cxx
@@ -488,6 +488,11 @@ namespace build2
               {
                 // Scope variable.
                 //
+                if (var.visibility == variable_visibility::target)
+                  fail (ploc) << "variable " << var << " has target "
+                              << "visibility but assigned in a scope" <<
+                    info << "consider changing to '.../*: " << var << "'";
+
                 enter_scope sg (*this, move (n.dir));
                 variable (t, tt, var, att);
               }
@@ -604,13 +609,11 @@ namespace build2
                       //
                       if (att == type::prepend && lhs.extra == 2)
                         fail (at) << "prepend to a previously appended target "
-                                  << "type/pattern-specific variable "
-                                  << var.name;
+                                  << "type/pattern-specific variable " << var;
 
                       if (att == type::append && lhs.extra == 1)
                         fail (at) << "append to a previously prepended target "
-                                  << "type/pattern-specific variable "
-                                  << var.name;
+                                  << "type/pattern-specific variable " << var;
 
                       // Do untyped prepend/append.
                       //
@@ -620,7 +623,7 @@ namespace build2
 
                   if (lhs.extra != 0 && lhs.type != nullptr)
                     fail (at) << "typed prepend/append to target type/pattern-"
-                              << "specific variable " << var.name;
+                              << "specific variable " << var;
                 }
               }
 
@@ -723,6 +726,11 @@ namespace build2
         //
         variable_attributes (var);
 
+        if (var.visibility == variable_visibility::target)
+          fail (nloc) << "variable " << var << " has target visibility but "
+                      << "assigned in a scope" <<
+            info << "consider changing to '*: " << var << "'";
+
         variable (t, tt, var, tt);
 
         if (tt == type::newline)
@@ -1532,7 +1540,7 @@ namespace build2
       if (var.type == nullptr)
         var.type = type;
       else if (var.type != type)
-        fail (l) << "changing variable " << var.name << " type from "
+        fail (l) << "changing variable " << var << " type from "
                  << var.type->name << " to " << type->name;
     }
   }
@@ -2371,7 +2379,7 @@ namespace build2
               // @@ TMP this isn't proving to be particularly useful.
               //
               //if (var.name.find ('.') != string::npos)
-              //fail (loc) << "undefined/null namespace variable " << var.name;
+              //fail (loc) << "undefined/null namespace variable " << var;
 
               // See if we should set the NULL indicator.
               //
diff --git a/build2/scope.cxx b/build2/scope.cxx
index 885a8d2..9cbeca1 100644
--- a/build2/scope.cxx
+++ b/build2/scope.cxx
@@ -18,6 +18,8 @@ namespace build2
                  const target_type* gt, const string* gn,
                  size_t start_d) const
   {
+    assert (tt != nullptr || var.visibility != variable_visibility::target);
+
     size_t d (0);
 
     // Process target type/pattern-specific prepend/append values.
@@ -131,7 +133,10 @@ namespace build2
         }
       }
 
-      if (++d >= start_d)
+      // Note that we still increment the lookup depth so that we can compare
+      // depths of variables with different visibilities.
+      //
+      if (++d >= start_d && var.visibility != variable_visibility::target)
       {
         if (const value* v = s->vars.find (var))
           return make_pair (lookup (v, &s->vars), d);
@@ -142,6 +147,7 @@ namespace build2
       case variable_visibility::scope:
         s = nullptr;
         break;
+      case variable_visibility::target:
       case variable_visibility::project:
         s = s->root () ? nullptr : s->parent_scope ();
         break;
@@ -230,6 +236,8 @@ namespace build2
       }
       case variable_visibility::normal:
         break;
+      case variable_visibility::target:
+        assert (false);
       }
 
       return true;
diff --git a/build2/test/init.cxx b/build2/test/init.cxx
index bd03f00..5b01bce 100644
--- a/build2/test/init.cxx
+++ b/build2/test/init.cxx
@@ -40,12 +40,12 @@ namespace build2
 
         // Note: none are overridable.
         //
-        v.insert<bool>    ("test");
-        v.insert<name>    ("test.input");
-        v.insert<name>    ("test.output");
-        v.insert<name>    ("test.roundtrip");
-        v.insert<strings> ("test.options");
-        v.insert<strings> ("test.arguments");
+        v.insert<bool>    ("test",           variable_visibility::target);
+        v.insert<name>    ("test.input",     variable_visibility::project);
+        v.insert<name>    ("test.output",    variable_visibility::project);
+        v.insert<name>    ("test.roundtrip", variable_visibility::project);
+        v.insert<strings> ("test.options",   variable_visibility::project);
+        v.insert<strings> ("test.arguments", variable_visibility::project);
       }
     }
 
diff --git a/build2/variable b/build2/variable
index fb44bb4..000ac9c 100644
--- a/build2/variable
+++ b/build2/variable
@@ -80,9 +80,13 @@ namespace build2
 
   enum class variable_visibility
   {
+    target,   // Target and target type/pattern-specific.
     scope,    // This scope (no outer scopes).
     project,  // This project (no outer projects).
     normal    // All outer scopes.
+
+    // Note that the search for target type/pattern-specific terminates at
+    // the project boundary.
   };
 
   // variable
@@ -119,6 +123,9 @@ namespace build2
   inline bool
   operator== (const variable& x, const variable& y) {return x.name == y.name;}
 
+  inline ostream&
+  operator<< (ostream& os, const variable& v) {return os << v.name;}
+
   //
   //
   class value
@@ -697,8 +704,14 @@ namespace build2
   struct variable_pool: private variable_pool_base
   {
     const variable&
+    insert (string name, variable_visibility v = variable_visibility::normal)
+    {
+      return insert (move (name), nullptr, v, false);
+    }
+
+    const variable&
     insert (string name,
-            bool overridable = false,
+            bool overridable,
             variable_visibility v = variable_visibility::normal)
     {
       return insert (move (name), nullptr, v, overridable);
@@ -706,8 +719,15 @@ namespace build2
 
     template <typename T>
     const variable&
+    insert (string name, variable_visibility v = variable_visibility::normal)
+    {
+      return insert (move (name), &value_traits<T>::value_type, v, false);
+    }
+
+    template <typename T>
+    const variable&
     insert (string name,
-            bool overridable = false,
+            bool overridable,
             variable_visibility v = variable_visibility::normal)
     {
       return insert (
diff --git a/buildfile b/buildfile
index 7e6d682..45bcdcc 100644
--- a/buildfile
+++ b/buildfile
@@ -11,4 +11,7 @@ file{INSTALL.cli config.guess config.sub manifest}
 
 include $d
 
-doc{INSTALL*}: install = false
+# Don't install tests or the INSTALL file.
+#
+dir{tests/}: install = false
+doc{INSTALL}@./: install = false