1 files changed, 35 insertions, 13 deletions

diff --git a/libbuild2/build/script/lexer.cxx b/libbuild2/build/script/lexer.cxx
index d849ac9..e0d87fe 100644
--- a/libbuild2/build/script/lexer.cxx
+++ b/libbuild2/build/script/lexer.cxx
@@ -35,10 +35,7 @@ namespace build2
         bool q (true); // quotes
 
         if (!esc)
-        {
-          assert (!state_.empty ());
-          esc = state_.top ().escapes;
-        }
+          esc = current_state ().escapes;
 
         switch (m)
         {
@@ -78,6 +75,19 @@ namespace build2
             s2 = "      ";
             break;
           }
+        case lexer_mode::for_loop:
+          {
+            // Leading tokens of the for-loop. Like command_line but
+            // recognizes colon as a separator and lsbrace like value.
+            //
+            // Note that while sensing the form of the for-loop (`for x:...`
+            // vs `for x <...`) we need to make sure that the pre-parsed token
+            // types are valid for the execution phase.
+            //
+            s1 = ":=!|&<> $(#\t\n";
+            s2 = " ==          ";
+            break;
+          }
         default:
           {
             // Recognize special variable names ($>, $<, $~).
@@ -94,7 +104,7 @@ namespace build2
         }
 
         assert (ps == '\0');
-        state_.push (
+        mode_impl (
           state {m, data, nullopt, false, false, ps, s, n, q, *esc, s1, s2});
       }
 
@@ -103,12 +113,13 @@ namespace build2
       {
         token r;
 
-        switch (state_.top ().mode)
+        switch (mode ())
         {
         case lexer_mode::command_line:
         case lexer_mode::first_token:
         case lexer_mode::second_token:
         case lexer_mode::variable_line:
+        case lexer_mode::for_loop:
           r = next_line ();
           break;
         default: return base_lexer::next ();
@@ -128,7 +139,7 @@ namespace build2
         xchar c (get ());
         uint64_t ln (c.line), cn (c.column);
 
-        state st (state_.top ()); // Make copy (see first/second_token).
+        state st (current_state ()); // Make copy (see first/second_token).
         lexer_mode m (st.mode);
 
         auto make_token = [&sep, ln, cn] (type t)
@@ -141,9 +152,10 @@ namespace build2
         //
         if (st.lsbrace)
         {
-          assert (m == lexer_mode::variable_line);
+          assert (m == lexer_mode::variable_line ||
+                  m == lexer_mode::for_loop);
 
-          state_.top ().lsbrace = false; // Note: st is a copy.
+          current_state ().lsbrace = false; // Note: st is a copy.
 
           if (c == '[' && (!st.lsbrace_unsep || !sep))
             return make_token (type::lsbrace);
@@ -156,7 +168,7 @@ namespace build2
         // we push any new mode (e.g., double quote).
         //
         if (m == lexer_mode::first_token || m == lexer_mode::second_token)
-          state_.pop ();
+          expire_mode ();
 
         // NOTE: remember to update mode() if adding new special characters.
 
@@ -167,7 +179,7 @@ namespace build2
             // Expire variable value mode at the end of the line.
             //
             if (m == lexer_mode::variable_line)
-              state_.pop ();
+              expire_mode ();
 
             sep = true; // Treat newline as always separated.
             return make_token (type::newline);
@@ -179,11 +191,20 @@ namespace build2
         case '(': return make_token (type::lparen);
         }
 
+        if (m == lexer_mode::for_loop)
+        {
+          switch (c)
+          {
+          case ':': return make_token (type::colon);
+          }
+        }
+
         // Command line operator/separators.
         //
         if (m == lexer_mode::command_line ||
             m == lexer_mode::first_token  ||
-            m == lexer_mode::second_token)
+            m == lexer_mode::second_token ||
+            m == lexer_mode::for_loop)
         {
           switch (c)
           {
@@ -205,7 +226,8 @@ namespace build2
         //
         if (m == lexer_mode::command_line ||
             m == lexer_mode::first_token  ||
-            m == lexer_mode::second_token)
+            m == lexer_mode::second_token ||
+            m == lexer_mode::for_loop)
         {
           if (optional<token> t = next_cmd_op (c, sep))
             return move (*t);