Cleanup context.hxx and its usage

25 files changed, 341 insertions, 334 deletions

diff --git a/libbuild2/algorithm.ixx b/libbuild2/algorithm.ixx
index a3fa906..6bc771e 100644
--- a/libbuild2/algorithm.ixx
+++ b/libbuild2/algorithm.ixx
@@ -4,6 +4,7 @@
 
 #include <libbuild2/rule.hxx>
 #include <libbuild2/context.hxx>
+#include <libbuild2/scheduler.hxx>
 
 #include <libbuild2/export.hxx>
 
diff --git a/libbuild2/bash/init.cxx b/libbuild2/bash/init.cxx
index 17c9ddd..bd0e34b 100644
--- a/libbuild2/bash/init.cxx
+++ b/libbuild2/bash/init.cxx
@@ -5,7 +5,6 @@
 #include <libbuild2/bash/init.hxx>
 
 #include <libbuild2/scope.hxx>
-#include <libbuild2/context.hxx>
 #include <libbuild2/variable.hxx>
 #include <libbuild2/diagnostics.hxx>
 
@@ -54,10 +53,13 @@ namespace build2
         // Install into bin/<project>/ by default stripping the .bash
         // extension from <project> if present.
         //
-        const project_name& p (cast<project_name> (rs.vars[var_project]));
+        const project_name& p (project (rs));
 
-        install_path<bash> (bs, dir_path ("bin") /= project_base (p));
-        install_mode<bash> (bs, "644");
+        if (!p.empty ())
+        {
+          install_path<bash> (bs, dir_path ("bin") /= project_base (p));
+          install_mode<bash> (bs, "644");
+        }
       }
 
       // Register rules.
diff --git a/libbuild2/config/utility.txx b/libbuild2/config/utility.txx
index b422ff4..841c408 100644
--- a/libbuild2/config/utility.txx
+++ b/libbuild2/config/utility.txx
@@ -3,7 +3,7 @@
 // license   : MIT; see accompanying LICENSE file
 
 #include <libbuild2/scope.hxx>
-#include <libbuild2/context.hxx>
+#include <libbuild2/context.hxx> // current_mif
 
 namespace build2
 {
diff --git a/libbuild2/context.cxx b/libbuild2/context.cxx
index 2f5e2af..1cc8bbc 100644
--- a/libbuild2/context.cxx
+++ b/libbuild2/context.cxx
@@ -341,6 +341,38 @@ namespace build2
   bool keep_going = false;
   bool dry_run = false;
 
+  void
+  set_current_mif (const meta_operation_info& mif)
+  {
+    if (current_mname != mif.name)
+    {
+      current_mname = mif.name;
+      global_scope->rw ().assign (var_build_meta_operation) = mif.name;
+    }
+
+    current_mif = &mif;
+    current_on = 0; // Reset.
+  }
+
+  void
+  set_current_oif (const operation_info& inner_oif,
+                   const operation_info* outer_oif,
+                   bool diag_noise)
+  {
+    current_oname = (outer_oif == nullptr ? inner_oif : *outer_oif).name;
+    current_inner_oif = &inner_oif;
+    current_outer_oif = outer_oif;
+    current_on++;
+    current_mode = inner_oif.mode;
+    current_diag_noise = diag_noise;
+
+    // Reset counters (serial execution).
+    //
+    dependency_count.store (0, memory_order_relaxed);
+    target_count.store (0, memory_order_relaxed);
+    skip_count.store (0, memory_order_relaxed);
+  }
+
   variable_overrides
   reset (const strings& cmd_vars)
   {
@@ -850,187 +882,4 @@ namespace build2
   const char var_extension[10] = "extension";
 
   const variable* var_build_meta_operation;
-
-  dir_path
-  src_out (const dir_path& out, const scope& r)
-  {
-    assert (r.root ());
-    return src_out (out, r.out_path (), r.src_path ());
-  }
-
-  dir_path
-  out_src (const dir_path& src, const scope& r)
-  {
-    assert (r.root ());
-    return out_src (src, r.out_path (), r.src_path ());
-  }
-
-  dir_path
-  src_out (const dir_path& o,
-           const dir_path& out_root, const dir_path& src_root)
-  {
-    assert (o.sub (out_root));
-    return src_root / o.leaf (out_root);
-  }
-
-  dir_path
-  out_src (const dir_path& s,
-           const dir_path& out_root, const dir_path& src_root)
-  {
-    assert (s.sub (src_root));
-    return out_root / s.leaf (src_root);
-  }
-
-  // diag_do(), etc.
-  //
-  string
-  diag_do (const action&)
-  {
-    const meta_operation_info& m (*current_mif);
-    const operation_info& io (*current_inner_oif);
-    const operation_info* oo (current_outer_oif);
-
-    string r;
-
-    // perform(update(x))   -> "update x"
-    // configure(update(x)) -> "configure updating x"
-    //
-    if (m.name_do.empty ())
-      r = io.name_do;
-    else
-    {
-      r = m.name_do;
-
-      if (io.name_doing[0] != '\0')
-      {
-        r += ' ';
-        r += io.name_doing;
-      }
-    }
-
-    if (oo != nullptr)
-    {
-      r += " (for ";
-      r += oo->name;
-      r += ')';
-    }
-
-    return r;
-  }
-
-  void
-  diag_do (ostream& os, const action& a, const target& t)
-  {
-    os << diag_do (a) << ' ' << t;
-  }
-
-  string
-  diag_doing (const action&)
-  {
-    const meta_operation_info& m (*current_mif);
-    const operation_info& io (*current_inner_oif);
-    const operation_info* oo (current_outer_oif);
-
-    string r;
-
-    // perform(update(x))   -> "updating x"
-    // configure(update(x)) -> "configuring updating x"
-    //
-    if (!m.name_doing.empty ())
-      r = m.name_doing;
-
-    if (io.name_doing[0] != '\0')
-    {
-      if (!r.empty ()) r += ' ';
-      r += io.name_doing;
-    }
-
-    if (oo != nullptr)
-    {
-      r += " (for ";
-      r += oo->name;
-      r += ')';
-    }
-
-    return r;
-  }
-
-  void
-  diag_doing (ostream& os, const action& a, const target& t)
-  {
-    os << diag_doing (a) << ' ' << t;
-  }
-
-  string
-  diag_did (const action&)
-  {
-    const meta_operation_info& m (*current_mif);
-    const operation_info& io (*current_inner_oif);
-    const operation_info* oo (current_outer_oif);
-
-    string r;
-
-    // perform(update(x))   -> "updated x"
-    // configure(update(x)) -> "configured updating x"
-    //
-    if (!m.name_did.empty ())
-    {
-      r = m.name_did;
-
-      if (io.name_doing[0] != '\0')
-      {
-        r += ' ';
-        r += io.name_doing;
-      }
-    }
-    else
-      r += io.name_did;
-
-    if (oo != nullptr)
-    {
-      r += " (for ";
-      r += oo->name;
-      r += ')';
-    }
-
-    return r;
-  }
-
-  void
-  diag_did (ostream& os, const action& a, const target& t)
-  {
-    os << diag_did (a) << ' ' << t;
-  }
-
-  void
-  diag_done (ostream& os, const action&, const target& t)
-  {
-    const meta_operation_info& m (*current_mif);
-    const operation_info& io (*current_inner_oif);
-    const operation_info* oo (current_outer_oif);
-
-    // perform(update(x))   -> "x is up to date"
-    // configure(update(x)) -> "updating x is configured"
-    //
-    if (m.name_done.empty ())
-    {
-      os << t;
-
-      if (io.name_done[0] != '\0')
-        os << ' ' << io.name_done;
-
-      if (oo != nullptr)
-        os << " (for " << oo->name << ')';
-    }
-    else
-    {
-      if (io.name_doing[0] != '\0')
-        os << io.name_doing << ' ';
-
-      if (oo != nullptr)
-        os << "(for " << oo->name << ") ";
-
-      os << t << ' ' << m.name_done;
-    }
-  }
 }
diff --git a/libbuild2/context.hxx b/libbuild2/context.hxx
index 86867a1..ce9a996 100644
--- a/libbuild2/context.hxx
+++ b/libbuild2/context.hxx
@@ -8,7 +8,6 @@
 #include <libbuild2/types.hxx>
 #include <libbuild2/utility.hxx>
 
-#include <libbuild2/scope.hxx>
 #include <libbuild2/variable.hxx>
 #include <libbuild2/operation.hxx>
 #include <libbuild2/scheduler.hxx>
@@ -17,7 +16,9 @@
 
 namespace build2
 {
-  // Main (and only) scheduler. Started up and shut down in main().
+  class scope;
+
+  // Main scheduler. Started up and shut down in main().
   //
   LIBBUILD2_SYMEXPORT extern scheduler sched;
 
@@ -302,10 +303,10 @@ namespace build2
   LIBBUILD2_SYMEXPORT extern atomic_count target_count;
   LIBBUILD2_SYMEXPORT extern atomic_count skip_count;
 
-  void
+  LIBBUILD2_SYMEXPORT void
   set_current_mif (const meta_operation_info&);
 
-  void
+  LIBBUILD2_SYMEXPORT void
   set_current_oif (const operation_info& inner,
                    const operation_info* outer = nullptr,
                    bool diag_noise = true);
@@ -450,101 +451,6 @@ namespace build2
   // .meta_operation
   //
   LIBBUILD2_SYMEXPORT extern const variable* var_build_meta_operation;
-
-  // Utility.
-  //
-
-  // Return the project name or empty string if unnamed.
-  //
-  inline const project_name&
-  project (const scope& root)
-  {
-    auto l (root[var_project]);
-    return l ? cast<project_name> (l) : empty_project_name;
-  }
-
-  // Return the src/out directory corresponding to the given out/src. The
-  // passed directory should be a sub-directory of out/src_root.
-  //
-  LIBBUILD2_SYMEXPORT dir_path
-  src_out (const dir_path& out, const scope& root);
-
-  LIBBUILD2_SYMEXPORT dir_path
-  src_out (const dir_path& out,
-           const dir_path& out_root, const dir_path& src_root);
-
-  LIBBUILD2_SYMEXPORT dir_path
-  out_src (const dir_path& src, const scope& root);
-
-  LIBBUILD2_SYMEXPORT dir_path
-  out_src (const dir_path& src,
-           const dir_path& out_root, const dir_path& src_root);
-
-  // Action phrases, e.g., "configure update exe{foo}", "updating exe{foo}",
-  // and "updating exe{foo} is configured". Use like this:
-  //
-  // info << "while " << diag_doing (a, t);
-  //
-  class target;
-
-  struct diag_phrase
-  {
-    const action& a;
-    const target& t;
-    void (*f) (ostream&, const action&, const target&);
-  };
-
-  inline ostream&
-  operator<< (ostream& os, const diag_phrase& p)
-  {
-    p.f (os, p.a, p.t);
-    return os;
-  }
-
-  LIBBUILD2_SYMEXPORT string
-  diag_do (const action&);
-
-  LIBBUILD2_SYMEXPORT void
-  diag_do (ostream&, const action&, const target&);
-
-  inline diag_phrase
-  diag_do (const action& a, const target& t)
-  {
-    return diag_phrase {a, t, &diag_do};
-  }
-
-  LIBBUILD2_SYMEXPORT string
-  diag_doing (const action&);
-
-  LIBBUILD2_SYMEXPORT void
-  diag_doing (ostream&, const action&, const target&);
-
-  inline diag_phrase
-  diag_doing (const action& a, const target& t)
-  {
-    return diag_phrase {a, t, &diag_doing};
-  }
-
-  LIBBUILD2_SYMEXPORT string
-  diag_did (const action&);
-
-  LIBBUILD2_SYMEXPORT void
-  diag_did (ostream&, const action&, const target&);
-
-  inline diag_phrase
-  diag_did (const action& a, const target& t)
-  {
-    return diag_phrase {a, t, &diag_did};
-  }
-
-  LIBBUILD2_SYMEXPORT void
-  diag_done (ostream&, const action&, const target&);
-
-  inline diag_phrase
-  diag_done (const action& a, const target& t)
-  {
-    return diag_phrase {a, t, &diag_done};
-  }
 }
 
 #include <libbuild2/context.ixx>
diff --git a/libbuild2/context.ixx b/libbuild2/context.ixx
index 1364eb8..f947bd7 100644
--- a/libbuild2/context.ixx
+++ b/libbuild2/context.ixx
@@ -57,36 +57,4 @@ namespace build2
     sched.wait (start_count, *task_count);
     task_count = nullptr;
   }
-
-  inline void
-  set_current_mif (const meta_operation_info& mif)
-  {
-    if (current_mname != mif.name)
-    {
-      current_mname = mif.name;
-      global_scope->rw ().assign (var_build_meta_operation) = mif.name;
-    }
-
-    current_mif = &mif;
-    current_on = 0; // Reset.
-  }
-
-  inline void
-  set_current_oif (const operation_info& inner_oif,
-                   const operation_info* outer_oif,
-                   bool diag_noise)
-  {
-    current_oname = (outer_oif == nullptr ? inner_oif : *outer_oif).name;
-    current_inner_oif = &inner_oif;
-    current_outer_oif = outer_oif;
-    current_on++;
-    current_mode = inner_oif.mode;
-    current_diag_noise = diag_noise;
-
-    // Reset counters (serial execution).
-    //
-    dependency_count.store (0, memory_order_relaxed);
-    target_count.store (0, memory_order_relaxed);
-    skip_count.store (0, memory_order_relaxed);
-  }
 }
diff --git a/libbuild2/diagnostics.cxx b/libbuild2/diagnostics.cxx
index eab3b78..3375e00 100644
--- a/libbuild2/diagnostics.cxx
+++ b/libbuild2/diagnostics.cxx
@@ -8,6 +8,11 @@
 
 #include <libbutl/process-io.mxx>
 
+#include <libbuild2/scope.hxx>
+#include <libbuild2/action.hxx>
+#include <libbuild2/target.hxx>
+#include <libbuild2/context.hxx>
+
 using namespace std;
 
 namespace build2
@@ -135,4 +140,157 @@ namespace build2
   const basic_mark text  (nullptr, nullptr, nullptr); // No type/data/frame.
   const fail_mark  fail  ("error");
   const fail_end   endf;
+
+    // diag_do(), etc.
+  //
+  string
+  diag_do (const action&)
+  {
+    const meta_operation_info& m (*current_mif);
+    const operation_info& io (*current_inner_oif);
+    const operation_info* oo (current_outer_oif);
+
+    string r;
+
+    // perform(update(x))   -> "update x"
+    // configure(update(x)) -> "configure updating x"
+    //
+    if (m.name_do.empty ())
+      r = io.name_do;
+    else
+    {
+      r = m.name_do;
+
+      if (io.name_doing[0] != '\0')
+      {
+        r += ' ';
+        r += io.name_doing;
+      }
+    }
+
+    if (oo != nullptr)
+    {
+      r += " (for ";
+      r += oo->name;
+      r += ')';
+    }
+
+    return r;
+  }
+
+  void
+  diag_do (ostream& os, const action& a, const target& t)
+  {
+    os << diag_do (a) << ' ' << t;
+  }
+
+  string
+  diag_doing (const action&)
+  {
+    const meta_operation_info& m (*current_mif);
+    const operation_info& io (*current_inner_oif);
+    const operation_info* oo (current_outer_oif);
+
+    string r;
+
+    // perform(update(x))   -> "updating x"
+    // configure(update(x)) -> "configuring updating x"
+    //
+    if (!m.name_doing.empty ())
+      r = m.name_doing;
+
+    if (io.name_doing[0] != '\0')
+    {
+      if (!r.empty ()) r += ' ';
+      r += io.name_doing;
+    }
+
+    if (oo != nullptr)
+    {
+      r += " (for ";
+      r += oo->name;
+      r += ')';
+    }
+
+    return r;
+  }
+
+  void
+  diag_doing (ostream& os, const action& a, const target& t)
+  {
+    os << diag_doing (a) << ' ' << t;
+  }
+
+  string
+  diag_did (const action&)
+  {
+    const meta_operation_info& m (*current_mif);
+    const operation_info& io (*current_inner_oif);
+    const operation_info* oo (current_outer_oif);
+
+    string r;
+
+    // perform(update(x))   -> "updated x"
+    // configure(update(x)) -> "configured updating x"
+    //
+    if (!m.name_did.empty ())
+    {
+      r = m.name_did;
+
+      if (io.name_doing[0] != '\0')
+      {
+        r += ' ';
+        r += io.name_doing;
+      }
+    }
+    else
+      r += io.name_did;
+
+    if (oo != nullptr)
+    {
+      r += " (for ";
+      r += oo->name;
+      r += ')';
+    }
+
+    return r;
+  }
+
+  void
+  diag_did (ostream& os, const action& a, const target& t)
+  {
+    os << diag_did (a) << ' ' << t;
+  }
+
+  void
+  diag_done (ostream& os, const action&, const target& t)
+  {
+    const meta_operation_info& m (*current_mif);
+    const operation_info& io (*current_inner_oif);
+    const operation_info* oo (current_outer_oif);
+
+    // perform(update(x))   -> "x is up to date"
+    // configure(update(x)) -> "updating x is configured"
+    //
+    if (m.name_done.empty ())
+    {
+      os << t;
+
+      if (io.name_done[0] != '\0')
+        os << ' ' << io.name_done;
+
+      if (oo != nullptr)
+        os << " (for " << oo->name << ')';
+    }
+    else
+    {
+      if (io.name_doing[0] != '\0')
+        os << io.name_doing << ' ';
+
+      if (oo != nullptr)
+        os << "(for " << oo->name << ") ";
+
+      os << t << ' ' << m.name_done;
+    }
+  }
 }
diff --git a/libbuild2/diagnostics.hxx b/libbuild2/diagnostics.hxx
index 802cd3c..dbc8351 100644
--- a/libbuild2/diagnostics.hxx
+++ b/libbuild2/diagnostics.hxx
@@ -431,6 +431,74 @@ namespace build2
 
   LIBBUILD2_SYMEXPORT extern const fail_mark fail;
   LIBBUILD2_SYMEXPORT extern const fail_end  endf;
+
+  // Action phrases, e.g., "configure update exe{foo}", "updating exe{foo}",
+  // and "updating exe{foo} is configured". Use like this:
+  //
+  // info << "while " << diag_doing (a, t);
+  //
+  class scope;
+  class target;
+  struct action;
+
+  struct diag_phrase
+  {
+    const action& a;
+    const target& t;
+    void (*f) (ostream&, const action&, const target&);
+  };
+
+  inline ostream&
+  operator<< (ostream& os, const diag_phrase& p)
+  {
+    p.f (os, p.a, p.t);
+    return os;
+  }
+
+  LIBBUILD2_SYMEXPORT string
+  diag_do (const action&);
+
+  LIBBUILD2_SYMEXPORT void
+  diag_do (ostream&, const action&, const target&);
+
+  inline diag_phrase
+  diag_do (const action& a, const target& t)
+  {
+    return diag_phrase {a, t, &diag_do};
+  }
+
+  LIBBUILD2_SYMEXPORT string
+  diag_doing (const action&);
+
+  LIBBUILD2_SYMEXPORT void
+  diag_doing (ostream&, const action&, const target&);
+
+  inline diag_phrase
+  diag_doing (const action& a, const target& t)
+  {
+    return diag_phrase {a, t, &diag_doing};
+  }
+
+  LIBBUILD2_SYMEXPORT string
+  diag_did (const action&);
+
+  LIBBUILD2_SYMEXPORT void
+  diag_did (ostream&, const action&, const target&);
+
+  inline diag_phrase
+  diag_did (const action& a, const target& t)
+  {
+    return diag_phrase {a, t, &diag_did};
+  }
+
+  LIBBUILD2_SYMEXPORT void
+  diag_done (ostream&, const action&, const target&);
+
+  inline diag_phrase
+  diag_done (const action& a, const target& t)
+  {
+    return diag_phrase {a, t, &diag_done};
+  }
 }
 
 #endif // LIBBUILD2_DIAGNOSTICS_HXX
diff --git a/libbuild2/dump.cxx b/libbuild2/dump.cxx
index a866fe3..7d59891 100644
--- a/libbuild2/dump.cxx
+++ b/libbuild2/dump.cxx
@@ -7,7 +7,6 @@
 #include <libbuild2/scope.hxx>
 #include <libbuild2/target.hxx>
 #include <libbuild2/variable.hxx>
-#include <libbuild2/context.hxx>
 #include <libbuild2/diagnostics.hxx>
 
 using namespace std;
diff --git a/libbuild2/filesystem.txx b/libbuild2/filesystem.txx
index 6166082..057975a 100644
--- a/libbuild2/filesystem.txx
+++ b/libbuild2/filesystem.txx
@@ -4,7 +4,7 @@
 
 #include <type_traits> // is_base_of
 
-#include <libbuild2/context.hxx>
+#include <libbuild2/context.hxx> // dry_run
 #include <libbuild2/diagnostics.hxx>
 
 namespace build2
diff --git a/libbuild2/function.test.cxx b/libbuild2/function.test.cxx
index a9326f4..2380987 100644
--- a/libbuild2/function.test.cxx
+++ b/libbuild2/function.test.cxx
@@ -7,6 +7,7 @@
 #include <libbuild2/types.hxx>
 #include <libbuild2/utility.hxx>
 
+#include <libbuild2/scope.hxx>
 #include <libbuild2/parser.hxx>
 #include <libbuild2/context.hxx>
 #include <libbuild2/function.hxx>
diff --git a/libbuild2/in/init.cxx b/libbuild2/in/init.cxx
index 6ef996b..a067ec3 100644
--- a/libbuild2/in/init.cxx
+++ b/libbuild2/in/init.cxx
@@ -5,7 +5,6 @@
 #include <libbuild2/in/init.hxx>
 
 #include <libbuild2/scope.hxx>
-#include <libbuild2/context.hxx>
 #include <libbuild2/variable.hxx>
 #include <libbuild2/diagnostics.hxx>
 
diff --git a/libbuild2/install/rule.cxx b/libbuild2/install/rule.cxx
index afb5b29..48a404b 100644
--- a/libbuild2/install/rule.cxx
+++ b/libbuild2/install/rule.cxx
@@ -9,6 +9,7 @@
 
 #include <libbuild2/scope.hxx>
 #include <libbuild2/target.hxx>
+#include <libbuild2/context.hxx>
 #include <libbuild2/algorithm.hxx>
 #include <libbuild2/filesystem.hxx>
 #include <libbuild2/diagnostics.hxx>
diff --git a/libbuild2/operation.cxx b/libbuild2/operation.cxx
index 9d84cc2..168ed5c 100644
--- a/libbuild2/operation.cxx
+++ b/libbuild2/operation.cxx
@@ -9,6 +9,7 @@
 #include <libbuild2/file.hxx>
 #include <libbuild2/scope.hxx>
 #include <libbuild2/target.hxx>
+#include <libbuild2/context.hxx>
 #include <libbuild2/algorithm.hxx>
 #include <libbuild2/diagnostics.hxx>
 
diff --git a/libbuild2/parser.cxx b/libbuild2/parser.cxx
index 4c48440..c55d434 100644
--- a/libbuild2/parser.cxx
+++ b/libbuild2/parser.cxx
@@ -14,7 +14,6 @@
 #include <libbuild2/scope.hxx>
 #include <libbuild2/module.hxx>
 #include <libbuild2/target.hxx>
-#include <libbuild2/context.hxx>
 #include <libbuild2/function.hxx>
 #include <libbuild2/variable.hxx>
 #include <libbuild2/filesystem.hxx>
diff --git a/libbuild2/scope.hxx b/libbuild2/scope.hxx
index f69e822..0c4094b 100644
--- a/libbuild2/scope.hxx
+++ b/libbuild2/scope.hxx
@@ -12,12 +12,13 @@
 #include <libbuild2/utility.hxx>
 
 #include <libbuild2/module.hxx>
+#include <libbuild2/context.hxx>
 #include <libbuild2/variable.hxx>
+#include <libbuild2/rule-map.hxx>
+#include <libbuild2/operation.hxx>
 #include <libbuild2/target-key.hxx>
 #include <libbuild2/target-type.hxx>
 #include <libbuild2/target-state.hxx>
-#include <libbuild2/rule-map.hxx>
-#include <libbuild2/operation.hxx>
 
 #include <libbuild2/export.hxx>
 
@@ -370,6 +371,28 @@ namespace build2
     return os << s.out_path ().representation (); // Always absolute.
   }
 
+  // Return the src/out directory corresponding to the given out/src. The
+  // passed directory should be a sub-directory of out/src_root.
+  //
+  dir_path
+  src_out (const dir_path& out, const scope& root);
+
+  dir_path
+  src_out (const dir_path& out,
+           const dir_path& out_root, const dir_path& src_root);
+
+  dir_path
+  out_src (const dir_path& src, const scope& root);
+
+  dir_path
+  out_src (const dir_path& src,
+           const dir_path& out_root, const dir_path& src_root);
+
+  // Return the project name or empty string if unnamed.
+  //
+  const project_name&
+  project (const scope& root);
+
   // Temporary scope. The idea is to be able to create a temporary scope in
   // order not to change the variables in the current scope.  Such a scope is
   // not entered in to the scope map. As a result it can only be used as a
diff --git a/libbuild2/scope.ixx b/libbuild2/scope.ixx
index 3498ae0..aa1247f 100644
--- a/libbuild2/scope.ixx
+++ b/libbuild2/scope.ixx
@@ -51,4 +51,41 @@ namespace build2
 
     return false;
   }
+
+  inline dir_path
+  src_out (const dir_path& out, const scope& r)
+  {
+    assert (r.root ());
+    return src_out (out, r.out_path (), r.src_path ());
+  }
+
+  inline dir_path
+  out_src (const dir_path& src, const scope& r)
+  {
+    assert (r.root ());
+    return out_src (src, r.out_path (), r.src_path ());
+  }
+
+  inline dir_path
+  src_out (const dir_path& o,
+           const dir_path& out_root, const dir_path& src_root)
+  {
+    assert (o.sub (out_root));
+    return src_root / o.leaf (out_root);
+  }
+
+  inline dir_path
+  out_src (const dir_path& s,
+           const dir_path& out_root, const dir_path& src_root)
+  {
+    assert (s.sub (src_root));
+    return out_root / s.leaf (src_root);
+  }
+
+  inline const project_name&
+  project (const scope& root)
+  {
+    auto l (root[var_project]);
+    return l ? cast<project_name> (l) : empty_project_name;
+  }
 }
diff --git a/libbuild2/search.cxx b/libbuild2/search.cxx
index 1ff9c73..917d750 100644
--- a/libbuild2/search.cxx
+++ b/libbuild2/search.cxx
@@ -6,7 +6,6 @@
 
 #include <libbuild2/scope.hxx>
 #include <libbuild2/target.hxx>
-#include <libbuild2/context.hxx>
 #include <libbuild2/filesystem.hxx>   // mtime()
 #include <libbuild2/prerequisite.hxx>
 #include <libbuild2/diagnostics.hxx>
diff --git a/libbuild2/spec.cxx b/libbuild2/spec.cxx
index 3ad6b7d..58b4541 100644
--- a/libbuild2/spec.cxx
+++ b/libbuild2/spec.cxx
@@ -4,7 +4,6 @@
 
 #include <libbuild2/spec.hxx>
 
-#include <libbuild2/context.hxx>
 #include <libbuild2/diagnostics.hxx>
 
 using namespace std;
diff --git a/libbuild2/target.hxx b/libbuild2/target.hxx
index 6d320d4..4bd11fe 100644
--- a/libbuild2/target.hxx
+++ b/libbuild2/target.hxx
@@ -16,6 +16,7 @@
 
 #include <libbuild2/scope.hxx>
 #include <libbuild2/action.hxx>
+#include <libbuild2/context.hxx>
 #include <libbuild2/variable.hxx>
 #include <libbuild2/target-key.hxx>
 #include <libbuild2/target-type.hxx>
@@ -27,13 +28,8 @@
 namespace build2
 {
   class rule;
-  class scope;
   class target;
 
-  // From <libbuild2/context.hxx>.
-  //
-  LIBBUILD2_SYMEXPORT extern size_t current_on;
-
   // From <libbuild2/algorithm.hxx>.
   //
   LIBBUILD2_SYMEXPORT const target&
diff --git a/libbuild2/test/rule.cxx b/libbuild2/test/rule.cxx
index a6796b4..1d11063 100644
--- a/libbuild2/test/rule.cxx
+++ b/libbuild2/test/rule.cxx
@@ -6,6 +6,7 @@
 
 #include <libbuild2/scope.hxx>
 #include <libbuild2/target.hxx>
+#include <libbuild2/context.hxx>
 #include <libbuild2/algorithm.hxx>
 #include <libbuild2/filesystem.hxx>
 #include <libbuild2/diagnostics.hxx>
diff --git a/libbuild2/utility.cxx b/libbuild2/utility.cxx
index cacb464..63fa609 100644
--- a/libbuild2/utility.cxx
+++ b/libbuild2/utility.cxx
@@ -10,6 +10,7 @@
 #include <iostream> // cerr
 
 #include <libbuild2/target.hxx>
+#include <libbuild2/context.hxx>
 #include <libbuild2/variable.hxx>
 #include <libbuild2/diagnostics.hxx>
 
diff --git a/libbuild2/variable.cxx b/libbuild2/variable.cxx
index beb169e..c921bbd 100644
--- a/libbuild2/variable.cxx
+++ b/libbuild2/variable.cxx
@@ -8,7 +8,6 @@
 
 #include <libbutl/filesystem.mxx> // path_match()
 
-#include <libbuild2/context.hxx>
 #include <libbuild2/diagnostics.hxx>
 
 using namespace std;
diff --git a/libbuild2/version/init.cxx b/libbuild2/version/init.cxx
index 8adbb29..a4e41d6 100644
--- a/libbuild2/version/init.cxx
+++ b/libbuild2/version/init.cxx
@@ -7,7 +7,6 @@
 #include <libbutl/manifest-parser.mxx>
 
 #include <libbuild2/scope.hxx>
-#include <libbuild2/context.hxx>
 #include <libbuild2/variable.hxx>
 #include <libbuild2/diagnostics.hxx>
 
diff --git a/libbuild2/version/utility.cxx b/libbuild2/version/utility.cxx
index c93a251..70daab1 100644
--- a/libbuild2/version/utility.cxx
+++ b/libbuild2/version/utility.cxx
@@ -7,6 +7,7 @@
 #include <libbutl/manifest-parser.mxx>
 #include <libbutl/manifest-serializer.mxx>
 
+#include <libbuild2/context.hxx>
 #include <libbuild2/diagnostics.hxx>
 
 using namespace butl;