Initial buildfile parser implementation

g++-4.9 -std=c++14 -g -I../../.. -o driver driver.cxx ../../../build/lexer.cxx ../../../build/parser.cxx && ./driver

1 files changed, 167 insertions, 0 deletions

diff --git a/build/parser.cxx b/build/parser.cxx
new file mode 100644
index 0000000..669ac8b
--- /dev/null
+++ b/build/parser.cxx
@@ -0,0 +1,167 @@
+// file      : build/parser.cxx -*- C++ -*-
+// copyright : Copyright (c) 2014-2015 Code Synthesis Tools CC
+// license   : MIT; see accompanying LICENSE file
+
+#include <build/parser>
+
+#include <iostream>
+
+#include <build/token>
+#include <build/lexer>
+
+using namespace std;
+
+namespace build
+{
+  // Output the token type and value in a format suitable for diagnostics.
+  //
+  ostream&
+  operator<< (ostream&, const token&);
+
+  typedef token_type type;
+  typedef token_punctuation punc;
+
+  void parser::
+  parse (istream& is, const path& p)
+  {
+    lexer l (is, p.string (), diag_);
+    lexer_ = &l;
+    path_ = &p;
+
+    token t (0, 0); // eos
+    type tt;
+
+    for (next (t, tt); tt != type::eos; )
+    {
+      // We always start with one or more names.
+      //
+      names (t, tt);
+
+      if (t.is (punc::colon))
+      {
+        next (t, tt);
+
+        if (tt == type::name || t.is (punc::lcbrace))
+          names (t, tt);
+
+        if (t.is (punc::newline))
+          next (t, tt);
+        else if (tt != type::eos)
+        {
+          error (t) << "expected newline insetad of " << t << endl;
+          throw parser_error ();
+        }
+
+        continue;
+      }
+
+      error (t) << "unexpected " << t << endl;
+      throw parser_error ();
+    }
+  }
+
+  void parser::
+  names (token& t, type& tt)
+  {
+    for (bool first (true);; first = false)
+    {
+      // Untyped name group, e.g., '{foo bar}'.
+      //
+      if (t.is (punc::lcbrace))
+      {
+        next (t, tt);
+        names (t, tt);
+
+        if (!t.is (punc::rcbrace))
+        {
+          error (t) << "expected '}' instead of " << t << endl;
+          throw parser_error ();
+        }
+
+        next (t, tt);
+        continue;
+      }
+
+      // Name.
+      //
+      if (tt == type::name)
+      {
+        string name (t.name ());
+
+        // See if this is a type name, that is, it is followed by '{'.
+        //
+        next (t, tt);
+
+        if (t.is (punc::lcbrace))
+        {
+          //cout << "type: " << name << endl;
+
+          //@@ TODO:
+          //
+          //   - detect nested typed name groups, e.g., 'cxx{hxx{foo}}'.
+          //
+          next (t, tt);
+          names (t, tt);
+
+          if (!t.is (punc::rcbrace))
+          {
+            error (t) << "expected '}' instead of " << t << endl;
+            throw parser_error ();
+          }
+
+          next (t, tt);
+          continue;
+        }
+
+        // This is a target, directory, or variable name.
+        //cout << "name: " << name << endl;
+        continue;
+      }
+
+      if (!first)
+        break;
+
+      error (t) << "expected name instead of " << t << endl;
+      throw parser_error ();
+    }
+  }
+
+  void parser::
+  next (token& t, token_type& tt)
+  {
+    t = lexer_->next ();
+    tt = t.type ();
+  }
+
+  ostream& parser::
+  error (const token& t)
+  {
+    return diag_ << path_->string () << ':' << t.line () << ':' <<
+      t.column () << ": error: ";
+  }
+
+  // Output the token type and value in a format suitable for diagnostics.
+  //
+  ostream&
+  operator<< (ostream& os, const token& t)
+  {
+    switch (t.type ())
+    {
+    case token_type::eos: os << "<end-of-stream>"; break;
+    case token_type::punctuation:
+      {
+        switch (t.punctuation ())
+        {
+        case token_punctuation::newline: os << "<newline>"; break;
+        case token_punctuation::colon:   os << "':'"; break;
+        case token_punctuation::lcbrace: os << "'{'"; break;
+        case token_punctuation::rcbrace: os << "'}'"; break;
+        }
+        break;
+      }
+    case token_type::name: os << '\'' << t.name () << '\''; break;
+    }
+
+    return os;
+  }
+}