diff --git a/doc/predef.qbk b/doc/predef.qbk
@@ -619,7 +619,7 @@ version information available in Predef. The basic use is simple:
 
 [teletype]
 ``
-import path-to-predef-src/check/predef
+import path-to-predef-src/tools/check/predef
     : check require
     : predef-check predef-require ;
 
@@ -635,7 +635,7 @@ For example:
 
 [teletype]
 ``
-import path-to-predef-src/check/predef
+import path-to-predef-src/tools/check/predef
     : check require
     : predef-check predef-require ;
 
@@ -663,7 +663,7 @@ to for more complex checks:
 
 [teletype]
 ``
-import path-to-predef-src/check/predef
+import path-to-predef-src/tools/check/predef
     : check require
     : predef-check predef-require ;
 
@@ -690,7 +690,7 @@ features in your programs:
 
 [teletype]
 ``
-import path-to-predef-src/check/predef
+import path-to-predef-src/tools/check/predef
     : check require
     : predef-check predef-require ;
 

diff --git a/test/build.jam b/test/build.jam
@@ -1,5 +1,5 @@
 #!/usr/bin/env b2 -a --verbose-test
-# Copyright Rene Rivera 2011-2013
+# Copyright Rene Rivera 2011-2016
 # Distributed under the Boost Software License, Version 1.0.
 # (See accompanying file LICENSE_1_0.txt or copy at
 # http://www.boost.org/LICENSE_1_0.txt)
@@ -64,4 +64,12 @@ test-suite predef :
 # Minimal testing done for predef for CI. Since
 # we don't have many we can just do all of them.
 alias minimal : predef ;
+
+# Full testing target for regular regression tests.
+alias full : predef ;
+
+# Extra's target. Nothing for Predef.
+alias extra ;
+
 explicit minimal ;
+explicit extra ;
diff --git a/check/build.jam → tools/check/build.jam b/check/build.jam → tools/check/build.jam
diff --git a/tools/check/predef.jam b/tools/check/predef.jam
@@ -0,0 +1,202 @@
+# Copyright Rene Rivera 2015
+# Distributed under the Boost Software License, Version 1.0.
+# (See accompanying file LICENSE_1_0.txt or copy at
+# http://www.boost.org/LICENSE_1_0.txt)
+
+# Defines rules that provide requirements based on checking
+# conditions using Boost Predef definitions and version numbers.
+
+import modules ;
+import project ;
+import feature ;
+import string ;
+import toolset ;
+import modules ;
+import path ;
+import "class" : new ;
+import regex ;
+
+# Create a project for our targets.
+project.extension predef check ;
+
+# Feature to pass check expressions to check programs.
+feature.feature predef-expression : : free ;
+
+# Checks the expressions and when used evaluates to the true-properties
+# if the expressions are all true. Otherwise evaluates to the
+# false-properties.
+rule check ( expressions + : language ? : true-properties * : false-properties * )
+{
+    # Default to C++ on the check context.
+    language ?= cpp ;
+
+    local project_target = [ project.target $(__name__) ] ;
+	project.push-current $(project_target) ;
+    local terms ;
+    local result ;
+    for expression in $(expressions)
+    {
+        if $(expression:L) in "and" "or"
+        {
+            terms += $(expression:L) ;
+        }
+        else
+        {
+            # Create the check run if we don't have one yet.
+            local key = [ MD5 $(language)::$(expression) ] ;
+            if ! ( $(key) in $(_checks_) )
+            {
+                _checks_ += $(key) ;
+                _message_(/check/predef//predef_check_cc_$(key)) = $(expression) ;
+                check_target $(language) $(key) : [ change_term_to_def $(expression) ] ;
+            }
+
+            terms += /check/predef//predef_check_cc_$(key) ;
+        }
+    }
+    local instance = [ new check-expression-evaluator
+        $(terms) : $(true-properties) : $(false-properties) ] ;
+    result = <conditional>@$(instance).check ;
+    project.pop-current ;
+    return $(result) ;
+}
+
+# Checks the expressions and when used evaluates to <build>no
+# if the expressions are all false. Otherwise evaluates to the
+# nothing.
+rule require ( expressions + : language ? )
+{
+    return [ check $(expressions) : $(language) : : <build>no ] ;
+}
+
+#############################################################################
+
+.c.ext = c ;
+.cpp.ext = cpp ;
+.objc.ext = m ;
+.objcpp.ext = mm ;
+
+# Check targets. Each needs to be compiled for different languages
+# even though they are all the same source code.
+local rule check_target ( language key : requirements * )
+{
+    # Need to use absolute paths because we don't know the
+    # context of the invocation which affects where the paths
+    # originate from.
+    local predef_jam
+        = [ modules.binding $(__name__) ] ;
+    local source_path
+        = $(predef_jam:D)/predef_check_cc_as_$(language).$(.$(language).ext) ;
+    local include_path
+        = $(predef_jam:D)/../../include ;
+    obj predef_check_cc_$(key)
+        : $(source_path)
+        : <include>$(include_path) $(requirements) ;
+    explicit predef_check_cc_$(key) ;
+    return predef_check_cc_$(key) ;
+}
+
+local rule change_term_to_def ( term )
+{
+    local parts = [ regex.split $(term) " " ] ;
+    if $(parts[3])
+    {
+        local version_number = [ regex.split $(parts[3]) "[.]" ] ;
+        if ! $(version_number[3]) { version_number += "0" ; }
+        if ! $(version_number[3]) { version_number += "0" ; }
+        parts = $(parts[1-2]) BOOST_VERSION_NUMBER($(version_number:J=",")) ;
+    }
+    return <define>CHECK=\"$(parts:J=" ")\" ;
+}
+
+class check-expression-evaluator
+{
+    import configure ;
+
+    rule __init__ ( expression + : true-properties * : false-properties * )
+    {
+        self.expression = $(expression) ;
+        self.true-properties = $(true-properties) ;
+        self.false-properties = $(false-properties) ;
+    }
+
+    rule check ( properties * )
+    {
+        local to-eval ;
+        local tokens = "and" "or" ;
+        # Go through the expression and: eval the target values,
+        # and normalize to a full expression.
+        for local term in $(self.expression)
+        {
+            if ! ( $(term:L) in $(tokens) )
+            {
+                # A value is a target reference that will evan to "true"
+                # or "false".
+                if $(to-eval[-1]:L) && ! ( $(to-eval[-1]:L) in $(tokens) )
+                {
+                    # Default to "and" operation.
+                    to-eval += "and" ;
+                }
+                local message = [ modules.peek predef : _message_($(term)) ] ;
+                if [ configure.builds $(term) : $(properties) : $(message) ]
+                {
+                    to-eval += "true" ;
+                }
+                else
+                {
+                    to-eval += "false" ;
+                }
+            }
+            else
+            {
+                to-eval += $(term) ;
+            }
+        }
+        # Eval full the expression.
+        local eval-result = [ eval $(to-eval) ] ;
+        # And resolve true/false properties.
+        if $(eval-result) = "true"
+        {
+            return $(self.true-properties) ;
+        }
+        else
+        {
+            return $(self.false-properties) ;
+        }
+    }
+
+    rule eval ( e * )
+    {
+        local r ;
+        if $(e[1]) && $(e[2]) && $(e[3])
+        {
+            if $(e[2]) = "and"
+            {
+                if $(e[1]) = "true" && $(e[3]) = "true"
+                {
+                    r = [ eval "true" $(e[4-]) ] ;
+                }
+                else
+                {
+                    r = [ eval "false" $(e[4-]) ] ;
+                }
+            }
+            else if $(e[2]) = "or"
+            {
+                if $(e[1]) = "true" || $(e[3]) = "true"
+                {
+                    r = [ eval "true" $(e[4-]) ] ;
+                }
+                else
+                {
+                    r = [ eval "false" $(e[4-]) ] ;
+                }
+            }
+        }
+        else
+        {
+            r = $(e[1]) ;
+        }
+        return $(r) ;
+    }
+}
diff --git a/check/predef_check.h → tools/check/predef_check.h b/check/predef_check.h → tools/check/predef_check.h
diff --git a/check/predef_check_as_c.c → tools/check/predef_check_as_c.c b/check/predef_check_as_c.c → tools/check/predef_check_as_c.c
diff --git a/check/predef_check_as_cpp.cpp → tools/check/predef_check_as_cpp.cpp b/check/predef_check_as_cpp.cpp → tools/check/predef_check_as_cpp.cpp
diff --git a/check/predef_check_as_objc.m → tools/check/predef_check_as_objc.m b/check/predef_check_as_objc.m → tools/check/predef_check_as_objc.m
diff --git a/check/predef_check_as_objcpp.mm → tools/check/predef_check_as_objcpp.mm b/check/predef_check_as_objcpp.mm → tools/check/predef_check_as_objcpp.mm
diff --git a/check/predef_check_cc.h → tools/check/predef_check_cc.h b/check/predef_check_cc.h → tools/check/predef_check_cc.h
diff --git a/check/predef_check_cc_as_c.c → tools/check/predef_check_cc_as_c.c b/check/predef_check_cc_as_c.c → tools/check/predef_check_cc_as_c.c
diff --git a/check/predef_check_cc_as_cpp.cpp → tools/check/predef_check_cc_as_cpp.cpp b/check/predef_check_cc_as_cpp.cpp → tools/check/predef_check_cc_as_cpp.cpp
diff --git a/check/predef_check_cc_as_objc.m → tools/check/predef_check_cc_as_objc.m b/check/predef_check_cc_as_objc.m → tools/check/predef_check_cc_as_objc.m
diff --git a/check/predef_check_cc_as_objcpp.mm → tools/check/predef_check_cc_as_objcpp.mm b/check/predef_check_cc_as_objcpp.mm → tools/check/predef_check_cc_as_objcpp.mm