diff --git a/compiler/src/thrift.y b/compiler/src/thrift.y
new file mode 100644
index 0000000..f0fa3c4
--- /dev/null
+++ b/compiler/src/thrift.y
@@ -0,0 +1,318 @@
+%{
+
+/**
+ * Thrift parser.
+ *
+ * This parser is used on a thrift definition file.
+ *
+ * @author Mark Slee <mcslee@facebook.com>
+ */
+
+#include <stdio.h>
+#include "main.h"
+#include "globals.h"
+#include "parse/t_program.h"
+
+int y_field_val = 0;
+
+%}
+
+%union {
+  char*       id;
+  int         iconst;
+  t_type*     ttype;
+  t_typedef*  ttypedef;
+  t_enum*     tenum;
+  t_struct*   tstruct;
+  t_service*  tservice;
+  t_function* tfunction;
+  t_field*    tfield;
+  t_list*     tlist;
+  t_constant* tconstant;
+}
+
+/** Strings and constants */
+%token<id>     tok_identifier
+%token<iconst> tok_int_constant
+
+/** Base datatypes */
+%token tok_byte
+%token tok_string
+%token tok_i32
+%token tok_u32
+%token tok_i64
+%token tok_u64
+
+/** Complex Types */
+%token tok_map
+%token tok_list
+%token tok_set
+
+/** Function types */
+%token tok_void
+
+/** Modifiers */ 
+%token tok_async
+
+/** Thrift actions */
+%token tok_typedef
+%token tok_struct
+%token tok_function
+%token tok_service
+%token tok_enum
+
+/** Types */
+%type<ttype>     BaseType
+
+%type<ttypedef>  Typedef
+%type<ttype>     DefinitionType
+
+%type<tfield>    Field
+%type<ttype>     FieldType
+%type<tlist>     FieldList
+
+%type<tenum>     Enum
+%type<tenum>     EnumDefList
+%type<tconstant> EnumDef
+
+%type<tstruct>   Struct
+
+%type<tservice>  Service
+
+%type<tfunction> Function
+%type<id>        FunctionModifiers
+%type<ttype>     FunctionType
+%type<tservice>  FunctionList
+
+%%
+
+/** Thrift Grammar */
+
+Program:
+  DefinitionList
+  {
+    pdebug("Program -> DefinitionList");
+  }
+
+DefinitionList:
+  DefinitionList Definition
+    {
+      pdebug("DefinitionList -> DefinitionList Definition");
+    }
+|
+    {
+      pdebug("DefinitionList -> ");
+    }
+
+Definition:
+  Typedef
+    {
+      pdebug("Definition -> Typedef");
+      g_program->add_typedef($1);
+    }
+| Enum
+    {
+      pdebug("Definition -> Enum");
+      g_program->add_enum($1);
+    }
+| Struct
+    {
+      pdebug("Definition -> Struct");
+      g_program->add_struct($1);
+    }
+| Service
+    {
+      pdebug("Definition -> Service");
+      g_program->add_service($1);
+    }  
+
+Typedef:
+  tok_typedef DefinitionType tok_identifier
+    {
+      pdebug("TypeDef -> tok_typedef DefinitionType tok_identifier");
+      
+      t_typedef *td = new t_typedef($2, $3);
+      $$ = td;
+    }
+
+Enum:
+  tok_enum tok_identifier '{' EnumDefList '}'
+    {
+      pdebug("Enum -> tok_enum tok_identifier { EnumDefList }");
+      $$ = $4;
+      $$->set_name($2);
+    }
+
+EnumDefList:
+  EnumDefList ',' EnumDef
+    {
+      pdebug("EnumDefList -> EnumDefList EnumDef");
+      $$ = $1;
+      $$->append($3);
+    }
+| EnumDef
+    {
+      pdebug("EnumDefList -> EnumDef");
+      $$ = new t_enum;
+      $$->append($1);
+    }
+|
+    {
+      pdebug("EnumDefList -> ");
+      $$ = new t_enum;
+    }
+
+EnumDef:
+  tok_identifier '=' tok_int_constant
+    {
+      if ($3 < 0) {
+        printf("WARNING (%d): Negative value supplied for enum %s.\n", yylineno, $1);
+      }
+      pdebug("EnumDef => tok_identifier = tok_int_constant");
+      $$ = new t_constant($1, $3);
+    }
+|
+  tok_identifier
+    {
+      pdebug("EnumDef => tok_identifier");
+      $$ = new t_constant($1);
+    }
+
+Struct:
+  tok_struct tok_identifier '{' FieldList '}'
+    {
+      pdebug("Struct -> tok_struct tok_identifier { FieldList }");
+      $$ = new t_struct($2, $4);
+      y_field_val = 0;
+    }
+
+Service:
+  tok_service tok_identifier '{' FunctionList '}'
+    {
+      pdebug("Service -> tok_service tok_identifier { FunctionList }");
+      $$ = $4;
+      $$->set_name($2);
+    }
+
+FunctionList:
+  FunctionList Function
+    {
+      pdebug("FunctionList -> FunctionList Function");
+      $$ = $1;
+      $1->add_function($2);
+    }
+|
+    {
+      pdebug("FunctionList -> ");
+      $$ = new t_service;
+    }
+
+Function:
+  FunctionType FunctionModifiers tok_identifier '(' FieldList ')'
+    {
+      t_struct* fun_args = new t_struct("__targs", $5);
+      $$ = new t_function($1, $3, fun_args);
+      y_field_val = 0;
+    }
+
+FunctionModifiers:
+    {
+      /** TODO(mcslee): implement async modifier, etc. */
+      $$ = 0;
+    }
+
+FieldList:
+  FieldList ',' Field
+    {
+      pdebug("FieldList -> FieldList , Field");
+      $$ = $1;
+      $$->append($3);
+    }
+| Field
+    {
+      pdebug("FieldList -> Field");
+      $$ = new t_list;
+      $$->append($1);
+    }
+|
+    {
+      pdebug("FieldList -> ");
+      $$ = new t_list;
+    }
+
+Field:
+  FieldType tok_identifier '=' tok_int_constant
+    {
+      if ($4 < 0) {
+        yyerror("Negative value (%d) not allowed as a field key.", $4);
+      }
+      $$ = new t_field($1, $2, (uint32_t)$4);
+      y_field_val = $4+1;
+    }
+| FieldType tok_identifier
+    {
+      printf("WARNING (%d): No field key specified for %s, resulting protocol may have conflicts or not be backwards compatible!\n", yylineno, $2);
+      $$ = new t_field($1, $2, y_field_val++);
+    }
+
+DefinitionType:
+  BaseType
+    {
+      pdebug("DefinitionType -> BaseType");
+      $$ = $1;
+    }
+
+FunctionType:
+  FieldType
+    {
+      $$ = $1;
+    }
+| tok_void
+    {
+      $$ = g_program->get_void_type();
+    }
+
+FieldType:
+  tok_identifier
+    {
+      /** TODO(mcslee): Dynamic type lookup */
+      yyerror("No dynamic type lookup yet.");
+    }
+| BaseType
+    {
+      $$ = $1;
+    }
+
+BaseType:
+  tok_string
+    {
+      pdebug("BaseType -> tok_string");
+      $$ = g_program->get_string_type();
+    }
+| tok_byte
+    {
+      pdebug("BaseType -> tok_byte");
+      $$ = g_program->get_byte_type();
+    }
+| tok_i32
+    {
+      pdebug("BaseType -> tok_i32");
+      $$ = g_program->get_i32_type();
+    }
+| tok_u32
+    {
+      pdebug("BaseType -> tok_u32");
+      $$ = g_program->get_u32_type();
+    }
+| tok_i64
+    {
+      pdebug("BaseType -> tok_i64");
+      $$ = g_program->get_i64_type();
+    }
+| tok_u64
+    {
+      pdebug("BaseType -> tok_u64");
+      $$ = g_program->get_u64_type();
+    }
+
+%%