13-single-var-storage.patch

[Akim Demaille]

I am still on my way to if/endif in *.am files.  I am unifying the
handling of the different kinds of variable so that I can extract
simple variable handling functions which are currently coded here and
there, and in particular in read_am_file.

Once I have extracted these, it should be simple to support if/endif
in *.am files.

Patch is several chunks because it took me several steps to reach the
right one.

Index: ChangeLog
from  Akim Demaille  <address@hidden>
        * automake.in (%am_var_defs): Replace with...
        (%var_is_am): this.
        (&handle_installdirs, &variable_value_as_list_worker, &read_am_file)
        (&file_contents, am_primary_&prefixes): Adjust.
        (&variable_defined, &define_variable): The actual semantics is
        `user defined'.
        (&read_main_am_file): Assert the var is user defined when
        outputting @var_list.

Index: automake.in
--- automake.in Thu, 08 Mar 2001 21:36:34 +0100 akim (am/f/39_automake.i 1.124 
755)
+++ automake.in Thu, 08 Mar 2001 21:36:46 +0100 akim (am/f/39_automake.i 1.124 
755)
@@ -448,10 +448,10 @@
 # variable was first defined with `+='.
 my %var_was_plus_eq;

-# This holds definitions of all variables defined in .am files.
+# Maps a variable name to true iff the variable was defined by Automake.
 # This is used during startup to determine which variables can be
-# assigned with `
-my %am_var_defs;
+# assigned with `+='.
+my %var_is_am;

 # For a variable or target $ITEM which is defined conditionally,
 # this holds a hash of the conditional values.  The keys of
@@ -632,7 +632,7 @@ sub initialize_per_input ()

     %var_was_plus_eq = ();

-    %am_var_defs = ();
+    %var_is_am = ();

     %conditional = ();

@@ -3827,7 +3827,7 @@ sub handle_installdirs ()
     $output_rules .=
       &file_contents ('install',
                      ('_am_installdirs'
-                      => $am_var_defs{'_am_installdirs'} || ''));
+                      => $contents{'_am_installdirs'} || ''));
 }


@@ -5606,15 +5606,15 @@ sub check_ambiguous_conditional ($$)
 # $BOOLEAN
 # &variable_defined ($VAR, [$COND])
 # ---------------------------------
-# See if a variable exists.  $VAR is the variable name, and $COND is
-# the condition which we should check.  If no condition is given, we
-# currently return true if the variable is defined under any
-# condition.
+# See if a variable exists, and is a user variable.  $VAR is the
+# variable name, and $COND is the condition which we should check.  If
+# no condition is given, we currently return true if the variable is
+# defined under any condition.
 sub variable_defined ($$)
 {
     my ($var, $cond) = @_;

-    if (defined $contents{$var})
+    if (defined $contents{$var} && !$var_is_am{$var})
     {
        if ($cond && $conditional{$var})
        {
@@ -5990,7 +5990,7 @@ sub variable_value_as_list_worker
     my ($var, $cond, $parent) = @_;
     my @result = ();

-    if (! defined $contents{$var} && ! defined $am_var_defs{$var})
+    if (! defined $contents{$var})
     {
         if (defined $targets{$var})
          {
@@ -6034,13 +6034,6 @@ sub variable_value_as_list_worker
            }
        }
     }
-    elsif (defined $am_var_defs{$var})
-    {
-       $vars_scanned{$var} = 1;
-       &variable_conditionally_defined ($var, $parent);
-       $content_seen{$var} = 1;
-       push (@result, &value_to_list ($var, $am_var_defs{$var}, $cond));
-    }
     else
     {
        $vars_scanned{$var} = 1;
@@ -6398,16 +6391,11 @@ sub read_am_file
                # If first assignment, set `+=' indicator.
                $var_was_plus_eq{$last_var_name} =
                    ($type eq '+'
-                    && ! defined $am_var_defs{$last_var_name});
+                    && ! $var_is_am{$last_var_name});
            }
-
+           $var_is_am{$last_var_name} = 0;
            if ($type eq '+')
            {
-               if (! defined $contents{$last_var_name}
-                   && defined $am_var_defs{$last_var_name})
-               {
-                   $contents{$last_var_name} = $am_var_defs{$last_var_name};
-               }
                if (substr ($contents{$last_var_name}, -1) eq "\n")
                {
                    # Insert a backslash before a trailing newline.
@@ -6791,17 +6781,17 @@ sub file_contents ($%)
            &prog_error ("$file:$.: macro `$var' with trailing backslash")
              if /\\$/;;
            # Accumulating variables must not be output.
-           $am_var_defs{$var} = ''
-             unless defined $am_var_defs{$var};
+           $contents{$var} = ''
+             unless defined $contents{$var};
+           $var_is_am{$var} = 1;
            if ($type eq '+')
              {
-               $am_var_defs{$var} .= ($am_var_defs{$var} && ' ') . $val;
+               $contents{$var} .= ($contents{$var} && ' ') . $val;
              }
            else
              {
-               $am_var_defs{$var} = $val;
-               $result_vars .= "$separator$comment$_\n"
-                 unless defined $contents{$var};
+               $contents{$var} = $val;
+               $result_vars .= "$separator$comment$_\n";
              }
            $comment = $separator = '';
        }
@@ -6860,6 +6850,11 @@ sub am_primary_prefixes
     $valid{'EXTRA'} = 0;
     foreach my $varname (keys %contents)
     {
+        # Automake is allowed to define variables that look like they
+        # are magic variables, such as INSTALL_DATA.
+        next
+         if $var_is_am{$varname};
+
        if ($varname =~ /^(nobase_)?(dist_|nodist_)?(.*)_$primary$/)
        {
            my ($base, $dist, $X) = ($1 || '', $2 || '', $3 || '');
Index: automake.in
--- automake.in Thu, 08 Mar 2001 21:38:32 +0100 akim (am/f/39_automake.i 1.125 
755)
+++ automake.in Thu, 08 Mar 2001 21:55:18 +0100 akim (am/f/39_automake.i 1.125 
755)
@@ -6783,7 +6781,8 @@ sub file_contents ($%)
            # Accumulating variables must not be output.
            $contents{$var} = ''
              unless defined $contents{$var};
-           $var_is_am{$var} = 1;
+           $var_is_am{$var} = 1
+             unless defined $var_is_am{$var};
            if ($type eq '+')
              {
                $contents{$var} .= ($contents{$var} && ' ') . $val;
@@ -6791,7 +6790,12 @@ sub file_contents ($%)
            else
              {
                $contents{$var} = $val;
-               $result_vars .= "$separator$comment$_\n";
+               # If the user has set some variables we were in charge
+               # of (which is detected by the first reading of
+               # `header-vars.am'), we must not output them.
+               $result_vars .= "$separator$comment$_\n"
+                 if $var_is_am{$var};
+
              }
            $comment = $separator = '';
        }
Index: automake.in
--- automake.in Thu, 08 Mar 2001 21:57:11 +0100 akim (am/f/39_automake.i 1.126 
755)
+++ automake.in Thu, 08 Mar 2001 22:41:09 +0100 akim (am/f/39_automake.i 1.126 
755)
@@ -6062,7 +6062,7 @@ sub variable_value_as_list

 # define_variable ($VAR, $VALUE)
 # ------------------------------
-# Define a new variable VAR to VALUE, but only if not already defined.
+# Define a new user variable VAR to VALUE, but only if not already defined.
 sub define_variable
 {
     my ($var, $value) = @_;
@@ -6072,6 +6072,7 @@ sub define_variable
        $output_vars .= $var . ' = ' . $value . "\n";
        $contents{$var} = $value;
        $content_seen{$var} = 1;
+       $var_is_am{$var} = 0;
     }
     elsif ($var_was_plus_eq{$var})
     {