From ea9d28c0e5fe16d5a0ade210f40cb98ea191d318 Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Thu, 20 Oct 2016 15:33:39 +0200
Subject: Use special mode for attribute lexing

---
 build2/lexer      | 14 +++++++++-----
 build2/lexer.cxx  | 34 +++++++++++++++++++++++++---------
 build2/parser.cxx | 12 +++---------
 3 files changed, 37 insertions(+), 23 deletions(-)

diff --git a/build2/lexer b/build2/lexer
index df8c852..f0a0fa6 100644
--- a/build2/lexer
+++ b/build2/lexer
@@ -21,15 +21,18 @@ namespace build2
   // characters (e.g., '+', '=') as special so that we can use them in the
   // variable values, e.g., 'foo = g++'. In contrast, in the variable mode, we
   // restrict certain character (e.g., '/') from appearing in the name. The
-  // eval mode is used in the evaluation context. Quoted are internal modes
-  // and should not be set explicitly.
+  // attribute mode is like value except it doesn't treat '{' and '}' as
+  // special (so we cannot have name groups in attributes). The eval mode is
+  // used in the evaluation context. Quoted are internal modes and should not
+  // be set explicitly.
   //
   // Note that the normal, value, and eval modes split words separated by the
   // pair character (to disable pairs one can pass '\0' as a pair character).
   //
-  // The alternnative modes must be set manually. The value mode is
-  // automatically reset after the end of the line. The variable mode is reset
-  // after the word token. And the eval mode is reset after the closing ')'.
+  // The alternnative modes must be set manually. The value mode automatically
+  // expires after the end of the line. The attribute mode expires after the
+  // closing ']'. The variable mode expires after the word token. And the eval
+  // mode expires after the closing ')'.
   //
   // Note that normally it is only safe to switch mode when the current token
   // is not quoted (or, more generally, when you are not in the double-quoted
@@ -49,6 +52,7 @@ namespace build2
       normal = base_type::value_next,
       variable,
       value,
+      attribute,
       eval,
       single_quoted,
       double_quoted,
diff --git a/build2/lexer.cxx b/build2/lexer.cxx
index 8760c13..f2426e7 100644
--- a/build2/lexer.cxx
+++ b/build2/lexer.cxx
@@ -54,6 +54,13 @@ namespace build2
         p = ps;
         break;
       }
+    case lexer_mode::attribute:
+      {
+        s1 = " $(]#\t\n";
+        s2 = "       ";
+        p = ps;
+        break;
+      }
     case lexer_mode::eval:
       {
         s1 = ":<>=! $(){}[]#\t\n";
@@ -87,11 +94,12 @@ namespace build2
     switch (m)
     {
     case lexer_mode::normal:
-    case lexer_mode::variable:
-    case lexer_mode::value: break;
-    case lexer_mode::eval: return next_eval ();
+    case lexer_mode::value:
+    case lexer_mode::attribute:
+    case lexer_mode::variable:      break;
+    case lexer_mode::eval:          return next_eval ();
     case lexer_mode::double_quoted: return next_quoted ();
-    default: assert (false); // Unhandled custom mode.
+    default:                        assert (false); // Unhandled custom mode.
     }
 
     bool sep (skip_spaces ());
@@ -109,8 +117,7 @@ namespace build2
 
     // Handle pair separator.
     //
-    if ((m == lexer_mode::normal || m == lexer_mode::value) &&
-        c == st.sep_pair)
+    if (c == st.sep_pair)
       return make_token (type::pair_separator);
 
     switch (c)
@@ -130,15 +137,24 @@ namespace build2
     case '{': return make_token (type::lcbrace);
     case '}': return make_token (type::rcbrace);
     case '[': return make_token (type::lsbrace);
-    case ']': return make_token (type::rsbrace);
+    case ']':
+      {
+        // Expire attribute mode after closing ']'.
+        //
+        if (m == lexer_mode::attribute)
+          state_.pop ();
+
+        return make_token (type::rsbrace);
+      }
     case '$': return make_token (type::dollar);
     case '(': return make_token (type::lparen);
     case ')': return make_token (type::rparen);
     }
 
-    // The following characters are not treated as special in the value mode.
+    // The following characters are not treated as special in the value and
+    // attribute modes.
     //
-    if (m != lexer_mode::value)
+    if (m != lexer_mode::value && m != lexer_mode::attribute)
     {
       switch (c)
       {
diff --git a/build2/parser.cxx b/build2/parser.cxx
index 64907b4..341ba34 100644
--- a/build2/parser.cxx
+++ b/build2/parser.cxx
@@ -1836,12 +1836,12 @@ namespace build2
     // Using '@' for attribute key-value pairs would be just too ugly. Seeing
     // that we control what goes into keys/values, let's use a much nicer '='.
     //
-    mode (lexer_mode::value, '=');
+    mode (lexer_mode::attribute, '=');
     next (t, tt);
 
-    if (tt != type::rsbrace && tt != type::newline && tt != type::eos)
+    if (tt != type::rsbrace)
     {
-      names ns (parse_names (t, tt, false, "key-value", nullptr));
+      names ns (parse_names (t, tt, false, "attribute", nullptr));
 
       if (!pre_parse_)
       {
@@ -1880,12 +1880,6 @@ namespace build2
       }
     }
 
-    // Manually expire the value mode if we haven't reached newline/eos (where
-    // it expires automatically).
-    //
-    if (mode () == lexer_mode::value)
-      expire_mode ();
-
     if (tt != type::rsbrace)
       fail (t) << "expected ']' instead of " << t;
 
-- 
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