diff --git a/code/compiler/06/CMakeLists.txt b/code/compiler/06/CMakeLists.txt
index 9109901..2ad7e91 100644
--- a/code/compiler/06/CMakeLists.txt
+++ b/code/compiler/06/CMakeLists.txt
@@ -18,6 +18,7 @@ add_executable(compiler
     env.cpp env.hpp
     type.cpp type.hpp
     error.cpp error.hpp
+    binop.cpp binop.hpp
     ${BISON_parser_OUTPUTS}
     ${FLEX_scanner_OUTPUTS}
     main.cpp
diff --git a/code/compiler/06/ast.cpp b/code/compiler/06/ast.cpp
index f8a88df..7da9306 100644
--- a/code/compiler/06/ast.cpp
+++ b/code/compiler/06/ast.cpp
@@ -2,16 +2,6 @@
 #include <ostream>
 #include "error.hpp"
 
-std::string op_name(binop op) {
-    switch(op) {
-        case PLUS: return "+";
-        case MINUS: return "-";
-        case TIMES: return "*";
-        case DIVIDE: return "/";
-    }
-    return "??";
-}
-
 void print_indent(int n, std::ostream& to) {
     while(n--) to << "  ";
 }
@@ -25,6 +15,10 @@ type_ptr ast_int::typecheck(type_mgr& mgr, const type_env& env) const {
     return type_ptr(new type_base("Int"));
 }
 
+void ast_int::compile(const env_ptr& env, std::vector<instruction_ptr>& into) const {
+    into.push_back(instruction_ptr(new instruction_pushint(value)));
+}
+
 void ast_lid::print(int indent, std::ostream& to) const {
     print_indent(indent, to);
     to << "LID: " << id << std::endl;
@@ -34,6 +28,10 @@ type_ptr ast_lid::typecheck(type_mgr& mgr, const type_env& env) const {
     return env.lookup(id);
 }
 
+void ast_lid::compile(const env_ptr& env, std::vector<instruction_ptr>& into) const {
+    into.push_back(instruction_ptr(new instruction_pushglobal(id)));
+}
+
 void ast_uid::print(int indent, std::ostream& to) const {
     print_indent(indent, to);
     to << "UID: " << id << std::endl;
@@ -43,6 +41,13 @@ type_ptr ast_uid::typecheck(type_mgr& mgr, const type_env& env) const {
     return env.lookup(id);
 }
 
+void ast_uid::compile(const env_ptr& env, std::vector<instruction_ptr>& into) const {
+    into.push_back(instruction_ptr(
+        env->has_variable(id) ?
+            (instruction*) new instruction_push(env->get_offset(id)) :
+            (instruction*) new instruction_pushglobal(id)));
+}
+
 void ast_binop::print(int indent, std::ostream& to) const {
     print_indent(indent, to);
     to << "BINOP: " << op_name(op) << std::endl;
@@ -64,6 +69,14 @@ type_ptr ast_binop::typecheck(type_mgr& mgr, const type_env& env) const {
     return return_type;
 }
 
+void ast_binop::compile(const env_ptr& env, std::vector<instruction_ptr>& into) const {
+    left->compile(env, into);
+    right->compile(env, into);
+    into.push_back(instruction_ptr(new instruction_pushglobal(op_name(op))));
+    into.push_back(instruction_ptr(new instruction_mkapp()));
+    into.push_back(instruction_ptr(new instruction_mkapp()));
+}
+
 void ast_app::print(int indent, std::ostream& to) const {
     print_indent(indent, to);
     to << "APP:" << std::endl;
@@ -81,6 +94,12 @@ type_ptr ast_app::typecheck(type_mgr& mgr, const type_env& env) const {
     return return_type;
 }
 
+void ast_app::compile(const env_ptr& env, std::vector<instruction_ptr>& into) const {
+    left->compile(env, into);
+    right->compile(env, into);
+    into.push_back(instruction_ptr(new instruction_mkapp()));
+}
+
 void ast_case::print(int indent, std::ostream& to) const {
     print_indent(indent, to);
     to << "CASE: " << std::endl;
@@ -111,6 +130,10 @@ type_ptr ast_case::typecheck(type_mgr& mgr, const type_env& env) const {
     return branch_type;
 }
 
+void ast_case::compile(const env_ptr& env, std::vector<instruction_ptr>& into) const {
+
+}
+
 void pattern_var::print(std::ostream& to) const {
     to << var;
 }
diff --git a/code/compiler/06/ast.hpp b/code/compiler/06/ast.hpp
index 232b39d..558fee1 100644
--- a/code/compiler/06/ast.hpp
+++ b/code/compiler/06/ast.hpp
@@ -12,8 +12,8 @@ struct ast {
 
     virtual void print(int indent, std::ostream& to) const = 0;
     virtual type_ptr typecheck(type_mgr& mgr, const type_env& env) const = 0;
-    virtual void compile(const env_ptr env,
-            std::vector<instruction>& into) const;
+    virtual void compile(const env_ptr& env,
+        std::vector<instruction_ptr>& into) const = 0;
 };
 
 using ast_ptr = std::unique_ptr<ast>;
@@ -64,6 +64,7 @@ struct ast_int : public ast {
 
     void print(int indent, std::ostream& to) const;
     type_ptr typecheck(type_mgr& mgr, const type_env& env) const;
+    void compile(const env_ptr& env, std::vector<instruction_ptr>& into) const;
 };
 
 struct ast_lid : public ast {
@@ -74,6 +75,7 @@ struct ast_lid : public ast {
 
     void print(int indent, std::ostream& to) const;
     type_ptr typecheck(type_mgr& mgr, const type_env& env) const;
+    void compile(const env_ptr& env, std::vector<instruction_ptr>& into) const;
 };
 
 struct ast_uid : public ast {
@@ -84,6 +86,7 @@ struct ast_uid : public ast {
 
     void print(int indent, std::ostream& to) const;
     type_ptr typecheck(type_mgr& mgr, const type_env& env) const;
+    void compile(const env_ptr& env, std::vector<instruction_ptr>& into) const;
 };
 
 struct ast_binop : public ast {
@@ -96,6 +99,7 @@ struct ast_binop : public ast {
 
     void print(int indent, std::ostream& to) const;
     type_ptr typecheck(type_mgr& mgr, const type_env& env) const;
+    void compile(const env_ptr& env, std::vector<instruction_ptr>& into) const;
 };
 
 struct ast_app : public ast {
@@ -107,6 +111,7 @@ struct ast_app : public ast {
 
     void print(int indent, std::ostream& to) const;
     type_ptr typecheck(type_mgr& mgr, const type_env& env) const;
+    void compile(const env_ptr& env, std::vector<instruction_ptr>& into) const;
 };
 
 struct ast_case : public ast {
@@ -118,6 +123,7 @@ struct ast_case : public ast {
 
     void print(int indent, std::ostream& to) const;
     type_ptr typecheck(type_mgr& mgr, const type_env& env) const;
+    void compile(const env_ptr& env, std::vector<instruction_ptr>& into) const;
 };
 
 struct pattern_var : public pattern {
diff --git a/code/compiler/06/binop.cpp b/code/compiler/06/binop.cpp
new file mode 100644
index 0000000..3a5f0ca
--- /dev/null
+++ b/code/compiler/06/binop.cpp
@@ -0,0 +1,21 @@
+#include "binop.hpp"
+
+std::string op_name(binop op) {
+    switch(op) {
+        case PLUS: return "+";
+        case MINUS: return "-";
+        case TIMES: return "*";
+        case DIVIDE: return "/";
+    }
+    return "??";
+}
+
+std::string op_action(binop op) {
+    switch(op) {
+        case PLUS: return "plus";
+        case MINUS: return "minus";
+        case TIMES: return "times";
+        case DIVIDE: return "divide";
+    }
+    return "??";
+}
diff --git a/code/compiler/06/binop.hpp b/code/compiler/06/binop.hpp
index 7c1382a..8d07858 100644
--- a/code/compiler/06/binop.hpp
+++ b/code/compiler/06/binop.hpp
@@ -1,4 +1,5 @@
 #pragma once
+#include <string>
 
 enum binop {
     PLUS,
@@ -7,3 +8,5 @@ enum binop {
     DIVIDE
 };
 
+std::string op_name(binop op);
+std::string op_action(binop op);
diff --git a/code/compiler/06/env.cpp b/code/compiler/06/env.cpp
new file mode 100644
index 0000000..818cf5d
--- /dev/null
+++ b/code/compiler/06/env.cpp
@@ -0,0 +1,23 @@
+#include "env.hpp"
+
+int env_var::get_offset(const std::string& name) const {
+    if(name == this->name) return 0;
+    if(parent) return parent->get_offset(name) + 1;
+    throw 0;
+}
+
+bool env_var::has_variable(const std::string& name) const {
+    if(name == this->name) return true;
+    if(parent) return parent->has_variable(name);
+    return false;
+}
+
+int env_offset::get_offset(const std::string& name) const {
+    if(parent) return parent->get_offset(name) + offset;
+    throw 0;
+}
+
+bool env_offset::has_variable(const std::string& name) const {
+    if(parent) return parent->has_variable(name);
+    return false;
+}
diff --git a/code/compiler/06/env.hpp b/code/compiler/06/env.hpp
index 718ddb9..02d9663 100644
--- a/code/compiler/06/env.hpp
+++ b/code/compiler/06/env.hpp
@@ -6,6 +6,7 @@ struct env {
     virtual ~env() = default;
 
     virtual int get_offset(const std::string& name) const = 0;
+    virtual bool has_variable(const std::string& name) const = 0;
 };
 
 using env_ptr = std::shared_ptr<env>;
@@ -17,7 +18,8 @@ struct env_var {
     env_var(std::string& n, env_ptr p)
         : name(std::move(n)), parent(std::move(p)) {}
 
-    virtual int get_offset(const std::string& name) const;
+    int get_offset(const std::string& name) const;
+    bool has_variable(const std::string& name) const;
 };
 
 struct env_offset {
@@ -27,5 +29,6 @@ struct env_offset {
     env_offset(int o, env_ptr p)
         : offset(o), parent(std::move(p)) {}
 
-    virtual int get_offset(const std::string& name) const;
+    int get_offset(const std::string& name) const;
+    bool has_variable(const std::string& name) const;
 };
diff --git a/content/blog/06_compiler_semantics.md b/content/blog/06_compiler_semantics.md
index ee90da4..cc21103 100644
--- a/content/blog/06_compiler_semantics.md
+++ b/content/blog/06_compiler_semantics.md
@@ -185,11 +185,26 @@ we see a variable that __isn't__ in the current environment, it must be a functi
 
 Having finished contemplating out method, it's time to define a signature:
 ```C++
-virtual void compile(const env_ptr env, std::vector<instruction>& into) const;
+virtual void compile(const env_ptr& env, std::vector<instruction_ptr>& into) const;
 ```
 
-Ah, but now we have to define "environment". Let's do that:
+Ah, but now we have to define "environment". Let's do that. Here's our header:
 
 {{< codeblock "C++" "compiler/06/env.hpp" >}}
 
+And here's the source file:
+
+{{< codeblock "C++" "compiler/06/env.cpp" >}}
+
+{{< todo >}}Explain the code drops. {{< /todo >}}
+
+It will also help to move some of the functions on the `binop` enum
+into a separate file. The new neader is pretty small:
+
+{{< codeblock "C++" "compiler/06/binop.hpp" >}}
+
+The new source file is not much longer:
+
+{{< codeblock "C++" "compiler/06/binop.cpp" >}}
+
 And now, we begin our implementation.