diff --git a/compiler/extended/internalprim.hh b/compiler/extended/internalprim.hh
new file mode 100644
index 0000000000..86278e87a0
--- /dev/null
+++ b/compiler/extended/internalprim.hh
@@ -0,0 +1,102 @@
+/************************************************************************
+ ************************************************************************
+    FAUST compiler
+    Copyright (C) 2003-2018 GRAME, Centre National de Creation Musicale
+    ---------------------------------------------------------------------
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation; either version 2.1 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ ************************************************************************
+ ************************************************************************/
+
+#include "xtended.hh"
+#include "simplify.hh"
+#include "sigorderrules.hh"
+
+enum InternalOp { kId, kRate, kLo, kHi };
+
+class InternalPrim : public xtended {
+    private:
+	InternalOp fOp;
+    public:
+	InternalPrim(InternalOp op, const char *name) : xtended(name), fOp(op) {}
+
+	virtual Tree computeSigOutput(const std::vector<Tree>& args)
+	{
+		Tree sig = simplify(args[0]);
+		int ret = -1;
+
+		switch (fOp) {
+		case kId:
+			ret = sig->serial();
+			break;
+		case kRate:
+			ret = getSigOrder(sig);
+			break;
+		case kLo: case kHi: {
+			typeAnnotation(sig, false);
+			interval i = getCertifiedSigType(sig)->getInterval();
+			return tree(fOp == kLo ? i.lo() : i.hi());
+		}
+		default:
+			faustassert(false);
+		}
+
+		return tree(ret);
+	}
+
+	virtual unsigned int arity() { return 1; }
+
+	virtual bool needCache() { return true; }
+
+	virtual ::Type inferSigType(ConstTypes args)
+	{
+		faustassert(false); return 0;
+	}
+	virtual int inferSigOrder(const std::vector<int>& args)
+	{
+		faustassert(false); return 0;
+	}
+	virtual ValueInst* generateCode(CodeContainer* container, Values& args, ::Type result, ConstTypes types)
+	{
+		faustassert(false); return 0;
+	}
+	virtual std::string generateCode(Klass* klass, const std::vector<std::string>& args, ConstTypes types)
+	{
+		faustassert(false); return 0;
+	}
+	virtual std::string generateLateq(Lateq* lateq, const std::vector<std::string>& args, ConstTypes types)
+	{
+		return "TODO";
+	}
+};
+
+static Tree add_internal_def(Tree defs, InternalOp op, const char *d_n)
+{
+	Tree id = boxIdent(d_n);
+	std::string x_n = std::string("internal.") + d_n;
+	InternalPrim *internal = new InternalPrim(op, x_n.c_str());
+	return cons(cons(id, internal->box()), defs);
+}
+
+static Tree mkInternalEnv()
+{
+	Tree defs = gGlobal->nil;
+
+	defs = add_internal_def(defs, kId, "id");
+	defs = add_internal_def(defs, kRate, "rate");
+	defs = add_internal_def(defs, kLo, "lo");
+	defs = add_internal_def(defs, kHi, "hi");
+
+	return boxWithLocalDef(boxEnvironment(), defs);
+}
diff --git a/compiler/global.cpp b/compiler/global.cpp
index 54b372204e..9cae1b950e 100644
--- a/compiler/global.cpp
+++ b/compiler/global.cpp
@@ -49,6 +49,7 @@
 #include "sourcereader.hh"
 #include "sqrtprim.hh"
 #include "tanprim.hh"
+#include "internalprim.hh"
 #include "tree.hh"
 #include "occur.hh"
 #include "enrobage.hh"
@@ -614,6 +615,8 @@ void global::init()
     // Predefined nil tree
     nil = tree(NIL);
 
+    gInternalEnv = mkInternalEnv();
+
     PROCESS = symbol("process");
 
     BOXTYPEPROP      = tree(symbol("boxTypeProp"));
diff --git a/compiler/global.hh b/compiler/global.hh
index 0be0ca213e..f780297bfb 100644
--- a/compiler/global.hh
+++ b/compiler/global.hh
@@ -326,7 +326,9 @@ struct global {
     xtended* gAtanPrim;
     xtended* gAtan2Prim;
     xtended* gAsinPrim;
- 
+
+    Tree gInternalEnv;
+
     // Signals
     Sym BOXIDENT;
     Sym BOXCUT;
diff --git a/compiler/parser/faustlexer.l b/compiler/parser/faustlexer.l
index 10871bd940..a1e4d25489 100644
--- a/compiler/parser/faustlexer.l
+++ b/compiler/parser/faustlexer.l
@@ -199,6 +199,8 @@ NSID     {ID}("::"{ID})*
 "sum"         return ISUM;
 "prod"        return IPROD;
 
+"internal"    return INTERNAL;
+
 "inputs"      return INPUTS;
 "outputs"     return OUTPUTS;
 
diff --git a/compiler/parser/faustparser.y b/compiler/parser/faustparser.y
index d11678a328..3c69d13c2c 100644
--- a/compiler/parser/faustparser.y
+++ b/compiler/parser/faustparser.y
@@ -218,6 +218,8 @@ inline Tree unquote(char* str)
 %token ISUM
 %token IPROD
 
+%token INTERNAL
+
 %token INPUTS
 %token OUTPUTS
 
@@ -589,6 +591,7 @@ primitive       : INT                           { $$ = boxInt(str2int(FAUSTtext)
                 | ffunction                     { $$ = boxFFun($1); }
                 | fconst                        { $$ = $1; }
                 | fvariable                     { $$ = $1; }
+                | INTERNAL                      { $$ = gGlobal->gInternalEnv; }
                 | COMPONENT LPAR uqstring RPAR  { $$ = boxComponent($3); }
                 | LIBRARY LPAR uqstring RPAR    { $$ = boxLibrary($3); }
                 | ENVIRONMENT LBRAQ stmtlist RBRAQ { $$ = boxWithLocalDef(boxEnvironment(),formatDefinitions($3)); }