diff --git a/analyzer-structs.rkt b/analyzer-structs.rkt
new file mode 100644
index 0000000..d177084
--- /dev/null
+++ b/analyzer-structs.rkt
@@ -0,0 +1,35 @@
+#lang typed/racket/base
+
+
+(require "expression-structs.rkt"
+         "lexical-structs.rkt"
+         "kernel-primitives.rkt"
+	 "il-structs.rkt")
+
+
+(provide (all-defined-out))
+
+
+;; Static knowledge about an expression.
+;;
+;; We try to keep at compile time a mapping from environment positions to
+;; statically known things, to generate better code.
+
+
+(define-type CompileTimeEnvironment (Listof CompileTimeEnvironmentEntry))
+
+(define-type CompileTimeEnvironmentEntry 
+  (U '?          ;; no knowledge
+     Prefix      ;; placeholder: necessary since the toplevel lives in the environment too
+     StaticallyKnownLam     ;; The value is a known lam
+     ModuleVariable         ;; The value is a known module variable
+     Const
+     ))
+
+
+(define-struct: StaticallyKnownLam ([name : (U Symbol LamPositionalName)]
+                                    [entry-point : Symbol]
+                                    [arity : Arity]) #:transparent)
+
+
+
diff --git a/analyzer.rkt b/analyzer.rkt
new file mode 100644
index 0000000..6d54fd7
--- /dev/null
+++ b/analyzer.rkt
@@ -0,0 +1,201 @@
+#lang typed/racket/base
+
+(provide (rename-out [-analyze analyze]))
+
+(require "analyzer-structs.rkt"
+	 "expression-structs.rkt"
+	 racket/match)
+
+
+
+
+(: current-expression-map
+   (Parameterof (HashTable Expression CompileTimeEnvironmentEntry)))
+(define current-expression-map (make-parameter 
+				((inst make-hasheq Expression
+				       CompileTimeEnvironmentEntry))))
+
+
+
+
+(: -analyze (Expression -> (HashTable Expression CompileTimeEnvironmentEntry)))
+(define (-analyze exp)
+  (parameterize ([current-expression-map 
+		  ((inst make-hasheq Expression CompileTimeEnvironmentEntry))])
+    (analyze exp '())
+    (current-expression-map)))
+
+
+
+
+(: analyze (Expression CompileTimeEnvironment -> 'ok))
+;; Finds all the lambdas in the expression.
+(define (analyze exp cenv)
+  (cond
+   [(Top? exp)
+    (analyze-Top exp cenv)]
+   [(Module? exp)
+    (analyze-Module exp cenv)]
+   [(Constant? exp)
+    (analyze-Constant exp cenv)]
+   [(LocalRef? exp)
+    (analyze-LocalRef exp cenv)]
+   [(ToplevelRef? exp)
+    (analyze-ToplevelRef exp cenv)]
+   [(ToplevelSet? exp)
+    (analyze-ToplevelSet exp cenv)]
+   [(Branch? exp)
+    (analyze-Branch exp cenv)]
+   [(Lam? exp)
+    (analyze-Lam exp cenv)]
+   [(CaseLam? exp)
+    (analyze-CaseLam exp cenv)]
+   [(EmptyClosureReference? exp)
+    (analyze-EmptyClosureReference exp cenv)]
+   [(Seq? exp)
+    (analyze-Seq exp cenv)]
+   [(Splice? exp)
+    (analyze-Splice exp cenv)]
+   [(Begin0? exp)
+    (analyze-Begin0 exp cenv)]
+   [(App? exp)
+    (analyze-App exp cenv)]
+   [(Let1? exp)
+    (analyze-Let1 exp cenv)]
+   [(LetVoid? exp)
+    (analyze-LetVoid exp cenv)]
+   [(InstallValue? exp)
+    (analyze-InstallValue exp cenv)]
+   [(BoxEnv? exp)
+    (analyze-BoxEnv exp cenv)]
+   [(LetRec? exp)
+    (analyze-LetRec exp cenv)]
+   [(WithContMark? exp)
+    (analyze-WithContMark exp cenv)]
+   [(ApplyValues? exp)
+    (analyze-ApplyValues exp cenv)]
+   [(DefValues? exp)
+    (analyze-DefValues exp cenv)]
+   [(PrimitiveKernelValue? exp)
+    (analyze-PrimitiveKernelValue exp cenv)]
+   [(VariableReference? exp)
+    (analyze-VariableReference exp cenv)]
+   [(Require? exp)
+    (analyze-Require exp cenv)]))
+
+
+
+
+(: analyze-Top (Top CompileTimeEnvironment -> 'ok))
+(define (analyze-Top exp cenv)
+  (match exp
+	 [(struct Top (prefix code))
+	  (analyze code (cons (Top-prefix exp) cenv))]))
+
+
+(: analyze-Module (Module CompileTimeEnvironment -> 'ok))
+(define (analyze-Module exp cenv)
+  'ok)
+
+(: analyze-Constant (Constant CompileTimeEnvironment -> 'ok))
+(define (analyze-Constant exp cenv)
+  'ok)
+
+(: analyze-LocalRef (LocalRef CompileTimeEnvironment -> 'ok))
+(define (analyze-LocalRef exp cenv)
+  'ok)
+
+(: analyze-ToplevelRef (ToplevelRef CompileTimeEnvironment -> 'ok))
+(define (analyze-ToplevelRef exp cenv)
+  'ok)
+
+(: analyze-ToplevelSet (ToplevelSet CompileTimeEnvironment -> 'ok))
+(define (analyze-ToplevelSet exp cenv)
+  'ok)
+
+(: analyze-Branch (Branch CompileTimeEnvironment -> 'ok))
+(define (analyze-Branch exp cenv)
+  'ok)
+
+(: analyze-Lam (Lam CompileTimeEnvironment -> 'ok))
+(define (analyze-Lam exp cenv)
+  'ok)
+(: analyze-CaseLam (CaseLam CompileTimeEnvironment -> 'ok))
+(define (analyze-CaseLam exp cenv)
+  'ok)
+
+(: analyze-EmptyClosureReference (EmptyClosureReference CompileTimeEnvironment -> 'ok))
+(define (analyze-EmptyClosureReference exp cenv)
+  'ok)
+
+(: analyze-Seq (Seq CompileTimeEnvironment -> 'ok))
+(define (analyze-Seq exp cenv)
+  'ok)
+
+(: analyze-Splice (Splice CompileTimeEnvironment -> 'ok))
+(define (analyze-Splice exp cenv)
+  'ok)
+
+(: analyze-Begin0 (Begin0 CompileTimeEnvironment -> 'ok))
+(define (analyze-Begin0 exp cenv)
+  'ok)
+
+(: analyze-App (App CompileTimeEnvironment -> 'ok))
+(define (analyze-App exp cenv)
+  'ok)
+
+(: analyze-Let1 (Let1 CompileTimeEnvironment -> 'ok))
+(define (analyze-Let1 exp cenv)
+  'ok)
+
+(: analyze-LetVoid (LetVoid CompileTimeEnvironment -> 'ok))
+(define (analyze-LetVoid exp cenv)
+  'ok)
+
+(: analyze-InstallValue (InstallValue CompileTimeEnvironment -> 'ok))
+(define (analyze-InstallValue exp cenv)
+  'ok)
+
+(: analyze-BoxEnv (BoxEnv CompileTimeEnvironment -> 'ok))
+(define (analyze-BoxEnv exp cenv)
+  'ok)
+
+(: analyze-LetRec (LetRec CompileTimeEnvironment -> 'ok))
+(define (analyze-LetRec exp cenv)
+  'ok)
+
+(: analyze-WithContMark (WithContMark CompileTimeEnvironment -> 'ok))
+(define (analyze-WithContMark exp cenv)
+  'ok)
+
+(: analyze-ApplyValues (ApplyValues CompileTimeEnvironment -> 'ok))
+(define (analyze-ApplyValues exp cenv)
+  'ok)
+
+(: analyze-DefValues (DefValues CompileTimeEnvironment -> 'ok))
+(define (analyze-DefValues exp cenv)
+  'ok)
+
+(: analyze-PrimitiveKernelValue (PrimitiveKernelValue CompileTimeEnvironment -> 'ok))
+(define (analyze-PrimitiveKernelValue exp cenv)
+  'ok)
+
+(: analyze-VariableReference (VariableReference CompileTimeEnvironment -> 'ok))
+(define (analyze-VariableReference exp cenv)
+  'ok)
+
+(: analyze-Require (Require CompileTimeEnvironment -> 'ok))
+(define (analyze-Require exp cenv)
+  'ok)
+
+
+
+
+(: annotate (Expression CompileTimeEnvironmentEntry -> 'ok))
+;; Accumulate information about an expression into the map.
+(define (annotate exp info)
+  (let ([my-map (current-expression-map)])
+    (hash-set! my-map exp info)
+    'ok))
+
+
diff --git a/compiler.rkt b/compiler.rkt
index 6addeb5..f3dedcf 100644
--- a/compiler.rkt
+++ b/compiler.rkt
@@ -8,6 +8,7 @@
          "optimize-il.rkt"
          "parameters.rkt"
          "sets.rkt"
+	 "analyzer-structs.rkt"
          racket/match
          racket/bool
          racket/list)
diff --git a/il-structs.rkt b/il-structs.rkt
index b602608..907e893 100644
--- a/il-structs.rkt
+++ b/il-structs.rkt
@@ -475,23 +475,6 @@
 
 
 
-;; Static knowledge about a value
-
-;; We try to keep at compile time a mapping from environment positions to
-;; statically known things, to generate better code.
-(define-struct: StaticallyKnownLam ([name : (U Symbol LamPositionalName)]
-                                    [entry-point : Symbol]
-                                    [arity : Arity]) #:transparent)
-
-(define-type CompileTimeEnvironmentEntry 
-  (U '?          ;; no knowledge
-     Prefix      ;; placeholder: necessary since the toplevel lives in the environment too
-     StaticallyKnownLam ;; The value is a known lam
-     ModuleVariable     ;; The value is a known module variable
-     Const
-     ))
-
-(define-type CompileTimeEnvironment (Listof CompileTimeEnvironmentEntry))