From 6b7075adc71104c5f6ad652b99fb753565eb67d8 Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Fri, 18 Nov 2016 17:28:46 +0200
Subject: Add function machinery, implement path.normalize()

Note that multi-argument functions are not yet "callable" since there is
no support for value packs.
---
 build2/function.cxx | 231 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 231 insertions(+)
 create mode 100644 build2/function.cxx

(limited to 'build2/function.cxx')

diff --git a/build2/function.cxx b/build2/function.cxx
new file mode 100644
index 0000000..91c5b3e
--- /dev/null
+++ b/build2/function.cxx
@@ -0,0 +1,231 @@
+// file      : build2/function.cxx -*- C++ -*-
+// copyright : Copyright (c) 2014-2016 Code Synthesis Ltd
+// license   : MIT; see accompanying LICENSE file
+
+#include <build2/function>
+
+using namespace std;
+
+namespace build2
+{
+  auto function_map::
+  insert (string name, function_overload f) -> iterator
+  {
+    // Sanity checks.
+    //
+    assert (f.arg_min <= f.arg_max &&
+            f.arg_types.size () <= f.arg_max &&
+            f.impl != nullptr);
+
+    auto i (map_.emplace (move (name), move (f)));
+
+    i->second.name = i->first.c_str ();
+    return i;
+  }
+
+  value function_map::
+  call (const string& name, vector_view<value> args, const location& loc)
+  {
+    auto print_call = [&name, &args] (ostream& os)
+    {
+      os << name << '(';
+
+      for (size_t i (0); i != args.size (); ++i)
+      {
+        const value_type* t (args[i].type);
+        os << (i != 0 ? ", " : "") << (t != nullptr ? t->name : "<untyped>");
+      }
+
+      os << ')';
+    };
+
+    auto print_fovl = [&name] (ostream& os, const function_overload& f)
+    {
+      os << name << '(';
+
+      bool v (f.arg_max == function_overload::arg_variadic);
+      size_t n (v ? max (f.arg_min, f.arg_types.size ()): f.arg_max);
+
+      // Handle variadic tail as the last pseudo-argument.
+      //
+      for (size_t i (0); i != n + (v ? 1 : 0); ++i)
+      {
+        if (i == f.arg_min)
+          os << (i != 0 ? " [" : "[");
+
+        os << (i != 0 ? ", " : "");
+
+        if (i == n) // Variadic tail (last).
+          os << "...";
+        else
+        {
+          // If count is greater than f.arg_typed, then we assume the rest are
+          // valid but untyped.
+          //
+          const optional<const value_type*> t (
+            i < f.arg_types.size () ? f.arg_types[i] : nullopt);
+
+          os << (t ? (*t != nullptr ? (*t)->name : "<untyped>") : "<anytype>");
+        }
+      }
+
+      if (n + (v ? 1 : 0) > f.arg_min)
+        os << ']';
+
+      os << ')';
+
+      if (f.qual_name)
+        os << ", qualified name " << f.qual_name;
+    };
+
+    // Overload resolution.
+    //
+    const function_overload* r (nullptr);
+
+    size_t count (args.size ());
+    auto ip (map_.equal_range (name));
+
+    for (auto it (ip.first); it != ip.second; ++it)
+    {
+      const function_overload& f (it->second);
+
+      // Argument count match.
+      //
+      if (count < f.arg_min || count > f.arg_max)
+        continue;
+
+      // Argument types match.
+      //
+      {
+        size_t i (0), n (min (count, f.arg_types.size ()));
+        for (; i != n; ++i)
+          if (f.arg_types[i] && *f.arg_types[i] != args[i].type)
+            break;
+
+        if (i != n)
+          continue;
+      }
+
+      if (r != nullptr)
+      {
+        diag_record dr (fail (loc));
+
+        dr << "ambiguous call to "; print_call (dr.os);
+        dr << info << " candidate: "; print_fovl (dr.os, *r);
+        dr << info << " candidate: "; print_fovl (dr.os, f);
+      }
+
+      r = &f; // Continue looking to detect ambiguities.
+    }
+
+    if (r == nullptr)
+    {
+      diag_record dr (fail (loc));
+
+      dr << "unmatched call to "; print_call (dr.os);
+
+      for (auto it (ip.first); it != ip.second; ++it)
+      {
+        const function_overload& f (it->second);
+
+        dr << info << " candidate: "; print_fovl (dr.os, f);
+      }
+    }
+
+    // Print the call location if the function fails.
+    //
+    auto g (
+      make_exception_guard (
+        [&loc, &print_call] ()
+        {
+          if (verb != 0)
+          {
+            diag_record dr (info (loc));
+            dr << "while calling "; print_call (dr.os);
+          }
+        }));
+
+    return r->impl (move (args), *r);
+  }
+
+  value function_family::
+  default_thunk (vector_view<value> args, const function_overload& f)
+  try
+  {
+    // Call the cast thunk.
+    //
+    struct cast_data // Prefix of function_cast::data.
+    {
+      value (*const thunk) (vector_view<value>, const void*);
+    };
+
+    auto d (reinterpret_cast<const cast_data*> (&f.data));
+    return d->thunk (move (args), d);
+  }
+  catch (const invalid_argument& e)
+  {
+    {
+      diag_record dr (error);
+      dr << "invalid argument";
+
+      const char* w (e.what ());
+      if (*w != '\0')
+        dr << ": " << w;
+    }
+
+    throw failed ();
+  }
+
+  const optional<const value_type*>* const function_args<>::types = nullptr;
+
+  void function_family::entry::
+  insert (string n, function_overload f) const
+  {
+    // Figure out qualification.
+    //
+    string qn;
+    size_t p (n.find ('.'));
+
+    if (p == string::npos)
+    {
+      if (!qual.empty ())
+      {
+        qn = qual;
+        qn += '.';
+        qn += n;
+      }
+    }
+    else if (p == 0)
+    {
+      assert (!qual.empty ());
+      n.insert (0, qual);
+    }
+
+    // First insert the qualified name and use its key for f.qual_name.
+    //
+    if (!qn.empty ())
+    {
+      auto i (functions.insert (move (qn), f));
+      f.qual_name = i->first.c_str ();
+    }
+
+    functions.insert (move (n), move (f));
+  }
+
+  // Static-initialize the function map and populate with builtin functions.
+  //
+  function_map functions;
+
+  void
+  path_functions (); // functions-path.cxx
+
+  struct functions_init
+  {
+    functions_init ()
+    {
+      path_functions ();
+    }
+  };
+
+  static const functions_init init_;
+}
-- 
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