diff --git a/VERSION b/VERSION
index 78bc1abd1..d9df1bbc0 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-0.10.0
+0.11.0
diff --git a/cli/smartcontract/smart_contract.go b/cli/smartcontract/smart_contract.go
index e2cc2084d..4425d8cb5 100644
--- a/cli/smartcontract/smart_contract.go
+++ b/cli/smartcontract/smart_contract.go
@@ -1,12 +1,7 @@
 package smartcontract
 
 import (
-	"encoding/hex"
 	"errors"
-	"fmt"
-	"io"
-	"os"
-	"strings"
 
 	"github.com/CityOfZion/neo-go/pkg/vm/compiler"
 	"github.com/urfave/cli"
@@ -43,39 +38,19 @@ func contractCompile(ctx *cli.Context) error {
 		return errors.New("not enough arguments")
 	}
 
+	o := &compiler.Options{
+		Outfile: ctx.String("out"),
+		Debug:   true,
+	}
+
 	src := ctx.Args()[0]
-	c := compiler.New()
-	if err := c.CompileSource(src); err != nil {
-		return err
-	}
-
-	filename := strings.Split(src, ".")[0]
-	filename = filename + ".avm"
-
-	out := ctx.String("out")
-	if len(out) > 0 {
-		filename = out
-	}
-
-	f, err := os.Create(out)
-	if err != nil {
-		return err
-	}
-
-	hx := hex.EncodeToString(c.Buffer().Bytes())
-	fmt.Println(hx)
-
-	_, err = io.Copy(f, c.Buffer())
-	return err
+	return compiler.CompileAndSave(src, o)
 }
 
 func contractDumpOpcode(ctx *cli.Context) error {
-	src := ctx.Args()[0]
-
-	c := compiler.New()
-	if err := c.CompileSource(src); err != nil {
-		return err
+	if len(ctx.Args()) == 0 {
+		return errors.New("not enough arguments")
 	}
-	c.DumpOpcode()
-	return nil
+	src := ctx.Args()[0]
+	return compiler.DumpOpcode(src)
 }
diff --git a/pkg/vm/compiler/README.md b/pkg/vm/compiler/README.md
new file mode 100644
index 000000000..254623b18
--- /dev/null
+++ b/pkg/vm/compiler/README.md
@@ -0,0 +1,35 @@
+# NEO-GO Compiler
+
+The neo-go compiler compiles Go programs to bytecode that the NEO virtual machine can understand.
+
+> The neo-go compiler is under very active development and will be updated on a weekly basis.
+
+## Currently supported
+- type checker
+- multiple assigns
+- types int, string and bool
+- struct types + method receives
+- functions
+- composite literals `[]int, []string`
+- basic if statements
+- binary expressions.
+- return statements
+
+## Not yet implemented
+- for loops
+- ranges
+- builtins (append, len, ..)
+- blockchain helpers (sha256, storage, ..)
+- import packages
+
+## Not supported
+Due to the limitations of the NEO virtual machine, features listed below will not be supported.
+- channels 
+- goroutines
+- multiple returns 
+
+## How to report bugs
+1. Make a proper testcase (example testcases can be found in the tests folder)
+2. Create an issue on Github 
+3. Make a PR with a reference to the created issue, containing the testcase that proves the bug
+4. Either you fix the bug yourself or wait for patch that solves the problem
diff --git a/pkg/vm/compiler/codegen.go b/pkg/vm/compiler/codegen.go
new file mode 100644
index 000000000..d480e14b2
--- /dev/null
+++ b/pkg/vm/compiler/codegen.go
@@ -0,0 +1,472 @@
+package compiler
+
+import (
+	"bytes"
+	"encoding/binary"
+	"go/ast"
+	"go/constant"
+	"go/token"
+	"go/types"
+	"log"
+
+	"github.com/CityOfZion/neo-go/pkg/vm"
+)
+
+const mainIdent = "Main"
+
+type codegen struct {
+	prog *bytes.Buffer
+
+	// Type information
+	typeInfo *types.Info
+
+	// a mapping of func identifiers with its scope.
+	funcs map[string]*funcScope
+
+	// current function being generated
+	fctx *funcScope
+
+	// Label table for recording jump destinations.
+	l []int
+}
+
+// newLabel creates a new label to jump to
+func (c *codegen) newLabel() (l int) {
+	l = len(c.l)
+	c.l = append(c.l, -1)
+	return
+}
+
+func (c *codegen) setLabel(l int) {
+	c.l[l] = c.pc() + 1
+}
+
+// pc return the program offset off the last instruction.
+func (c *codegen) pc() int {
+	return c.prog.Len() - 1
+}
+
+func (c *codegen) emitLoadConst(t types.TypeAndValue) {
+	switch typ := t.Type.(type) {
+	case *types.Basic:
+		switch typ.Kind() {
+		case types.Int:
+			val, _ := constant.Int64Val(t.Value)
+			emitInt(c.prog, val)
+		case types.String:
+			val := constant.StringVal(t.Value)
+			emitString(c.prog, val)
+		case types.Bool, types.UntypedBool:
+			val := constant.BoolVal(t.Value)
+			emitBool(c.prog, val)
+		}
+	default:
+		log.Fatalf("compiler don't know how to convert this constant: %v", t)
+	}
+}
+
+func (c *codegen) emitLoadLocal(name string) {
+	pos := c.fctx.loadLocal(name)
+	if pos < 0 {
+		log.Fatalf("cannot load local variable with position: %d", pos)
+	}
+
+	emitOpcode(c.prog, vm.Ofromaltstack)
+	emitOpcode(c.prog, vm.Odup)
+	emitOpcode(c.prog, vm.Otoaltstack)
+
+	emitInt(c.prog, int64(pos))
+	emitOpcode(c.prog, vm.Opickitem)
+}
+
+func (c *codegen) emitLoadStructField(sName, fName string) {
+	strct := c.fctx.loadStruct(sName)
+	pos := strct.loadField(fName)
+	emitInt(c.prog, int64(pos))
+	emitOpcode(c.prog, vm.Opickitem)
+}
+
+func (c *codegen) emitStoreLocal(pos int) {
+	emitOpcode(c.prog, vm.Ofromaltstack)
+	emitOpcode(c.prog, vm.Odup)
+	emitOpcode(c.prog, vm.Otoaltstack)
+
+	if pos < 0 {
+		log.Fatalf("invalid position to store local: %d", pos)
+	}
+
+	emitInt(c.prog, int64(pos))
+	emitInt(c.prog, 2)
+	emitOpcode(c.prog, vm.Oroll)
+	emitOpcode(c.prog, vm.Osetitem)
+}
+
+func (c *codegen) emitStoreStructField(sName, fName string) {
+	strct := c.fctx.loadStruct(sName)
+	pos := strct.loadField(fName)
+	emitInt(c.prog, int64(pos))
+	emitOpcode(c.prog, vm.Orot)
+	emitOpcode(c.prog, vm.Osetitem)
+}
+
+func (c *codegen) convertFuncDecl(decl *ast.FuncDecl) {
+	var (
+		f  *funcScope
+		ok bool
+	)
+
+	f, ok = c.funcs[decl.Name.Name]
+	if ok {
+		c.setLabel(f.label)
+	} else {
+		f = c.newFunc(decl)
+	}
+	c.fctx = f
+
+	emitInt(c.prog, f.stackSize())
+	emitOpcode(c.prog, vm.Onewarray)
+	emitOpcode(c.prog, vm.Otoaltstack)
+
+	// We need to handle methods, which in Go, is just syntactic sugar.
+	// The method receiver will be passed in as first argument.
+	// We check if this declaration has a receiver and load it into scope.
+	//
+	// FIXME: For now we will hard cast this to a struct. We can later finetune this
+	// to support other types.
+	if decl.Recv != nil {
+		for _, arg := range decl.Recv.List {
+			strct := c.fctx.newStruct()
+
+			ident := arg.Names[0]
+			strct.initializeFields(ident, c.typeInfo)
+			l := c.fctx.newLocal(ident.Name)
+			c.emitStoreLocal(l)
+		}
+	}
+
+	// Load the arguments in scope.
+	for _, arg := range decl.Type.Params.List {
+		name := arg.Names[0].Name // for now.
+		l := c.fctx.newLocal(name)
+		c.emitStoreLocal(l)
+	}
+
+	ast.Walk(c, decl.Body)
+}
+
+func (c *codegen) Visit(node ast.Node) ast.Visitor {
+	switch n := node.(type) {
+
+	case *ast.AssignStmt:
+		for i := 0; i < len(n.Lhs); i++ {
+			// resolve the whole right hand side.
+			ast.Walk(c, n.Rhs[i])
+			// check if we are assigning to a struct or an identifier
+			switch t := n.Lhs[i].(type) {
+			case *ast.Ident:
+				l := c.fctx.loadLocal(t.Name)
+				c.emitStoreLocal(l)
+
+			case *ast.SelectorExpr:
+				switch n := t.X.(type) {
+				case *ast.Ident:
+					c.emitLoadLocal(n.Name)                    // load the struct
+					c.emitStoreStructField(n.Name, t.Sel.Name) // store the field
+				default:
+					log.Fatal("nested selector assigns not supported yet")
+				}
+			}
+		}
+		return nil
+
+	case *ast.ReturnStmt:
+		if len(n.Results) > 1 {
+			log.Fatal("multiple returns not supported.")
+		}
+
+		emitOpcode(c.prog, vm.Ojmp)
+		emitOpcode(c.prog, vm.Opcode(0x03))
+		emitOpcode(c.prog, vm.Opush0)
+
+		if len(n.Results) > 0 {
+			ast.Walk(c, n.Results[0])
+		}
+
+		emitOpcode(c.prog, vm.Onop)
+		emitOpcode(c.prog, vm.Ofromaltstack)
+		emitOpcode(c.prog, vm.Odrop)
+		emitOpcode(c.prog, vm.Oret)
+		return nil
+
+	case *ast.IfStmt:
+		lIf := c.newLabel()
+		lElse := c.newLabel()
+		if n.Cond != nil {
+			ast.Walk(c, n.Cond)
+			emitJmp(c.prog, vm.Ojmpifnot, int16(lElse))
+		}
+
+		c.setLabel(lIf)
+		ast.Walk(c, n.Body)
+
+		if n.Else != nil {
+			// TODO: handle else statements.
+			// emitJmp(c.prog, vm.Ojmp, int16(lEnd))
+		}
+		c.setLabel(lElse)
+		if n.Else != nil {
+			ast.Walk(c, n.Else)
+		}
+		return nil
+
+	case *ast.BasicLit:
+		c.emitLoadConst(c.getTypeInfo(n))
+		return nil
+
+	case *ast.Ident:
+		if isIdentBool(n) {
+			c.emitLoadConst(makeBoolFromIdent(n, c.typeInfo))
+		} else {
+			c.emitLoadLocal(n.Name)
+		}
+		return nil
+
+	case *ast.CompositeLit:
+		switch t := n.Type.(type) {
+		case *ast.Ident:
+			typ := c.typeInfo.ObjectOf(t).Type().Underlying()
+			switch typ.(type) {
+			case *types.Struct:
+				c.convertStruct(n)
+			}
+
+		default:
+			ln := len(n.Elts)
+			for i := ln - 1; i >= 0; i-- {
+				c.emitLoadConst(c.getTypeInfo(n.Elts[i]))
+			}
+			emitInt(c.prog, int64(ln))
+			emitOpcode(c.prog, vm.Opack)
+		}
+		return nil
+
+	case *ast.BinaryExpr:
+		switch n.Op {
+		case token.LAND:
+			ast.Walk(c, n.X)
+			emitJmp(c.prog, vm.Ojmpifnot, int16(len(c.l)-1))
+			ast.Walk(c, n.Y)
+			return nil
+
+		case token.LOR:
+			ast.Walk(c, n.X)
+			emitJmp(c.prog, vm.Ojmpif, int16(len(c.l)-2))
+			ast.Walk(c, n.Y)
+			return nil
+
+		default:
+			// The AST package will try to resolve all basic literals for us.
+			// If the typeinfo.Value is not nil we know that the expr is resolved
+			// and needs no further action. e.g. x := 2 + 2 + 2 will be resolved to 6.
+			if tinfo := c.getTypeInfo(n); tinfo.Value != nil {
+				c.emitLoadConst(tinfo)
+				return c
+			}
+
+			ast.Walk(c, n.X)
+			ast.Walk(c, n.Y)
+
+			switch n.Op {
+			case token.ADD:
+				emitOpcode(c.prog, vm.Oadd)
+			case token.SUB:
+				emitOpcode(c.prog, vm.Osub)
+			case token.MUL:
+				emitOpcode(c.prog, vm.Omul)
+			case token.QUO:
+				emitOpcode(c.prog, vm.Odiv)
+			case token.LSS:
+				emitOpcode(c.prog, vm.Olt)
+			case token.LEQ:
+				emitOpcode(c.prog, vm.Olte)
+			case token.GTR:
+				emitOpcode(c.prog, vm.Ogt)
+			case token.GEQ:
+				emitOpcode(c.prog, vm.Ogte)
+			}
+			return nil
+		}
+
+	case *ast.CallExpr:
+		var (
+			f       *funcScope
+			ok      bool
+			numArgs = len(n.Args)
+		)
+
+		switch fun := n.Fun.(type) {
+		case *ast.Ident:
+			f, ok = c.funcs[fun.Name]
+			if !ok {
+				log.Fatalf("could not resolve function %s", fun.Name)
+			}
+		case *ast.SelectorExpr:
+			ast.Walk(c, fun.X)
+			f, ok = c.funcs[fun.Sel.Name]
+			if !ok {
+				log.Fatalf("could not resolve function %s", fun.Sel.Name)
+			}
+			// Dont forget to add 1 extra argument when its a method.
+			numArgs++
+		}
+
+		for _, arg := range n.Args {
+			ast.Walk(c, arg)
+		}
+		if numArgs == 2 {
+			emitOpcode(c.prog, vm.Oswap)
+		}
+		if numArgs == 3 {
+			emitInt(c.prog, 2)
+			emitOpcode(c.prog, vm.Oxswap)
+		}
+
+		// c# compiler adds a NOP (0x61) before every function call. Dont think its relevant
+		// and we could easily removed it, but to be consistent with the original compiler I
+		// will put them in. ^^
+		emitOpcode(c.prog, vm.Onop)
+		emitCall(c.prog, vm.Ocall, int16(f.label))
+		return nil
+
+	case *ast.SelectorExpr:
+		switch t := n.X.(type) {
+		case *ast.Ident:
+			c.emitLoadLocal(t.Name)                   // load the struct
+			c.emitLoadStructField(t.Name, n.Sel.Name) // load the field
+		default:
+			log.Fatal("nested selectors not supported yet")
+		}
+		return nil
+	}
+	return c
+}
+
+func (c *codegen) convertStruct(lit *ast.CompositeLit) {
+	emitOpcode(c.prog, vm.Onop)
+	emitInt(c.prog, int64(len(lit.Elts)))
+	emitOpcode(c.prog, vm.Onewstruct)
+	emitOpcode(c.prog, vm.Otoaltstack)
+
+	// Create a new struct scope to store the positions of its variables.
+	strct := c.fctx.newStruct()
+
+	for _, field := range lit.Elts {
+		f := field.(*ast.KeyValueExpr)
+		// Walk to resolve the expression of the value.
+		ast.Walk(c, f.Value)
+		l := strct.newField(f.Key.(*ast.Ident).Name)
+		c.emitStoreLocal(l)
+	}
+	emitOpcode(c.prog, vm.Ofromaltstack)
+}
+
+func (c *codegen) newFunc(decl *ast.FuncDecl) *funcScope {
+	f := newFuncScope(decl, c.newLabel())
+	c.funcs[f.name] = f
+	return f
+}
+
+func (c *codegen) getTypeInfo(expr ast.Expr) types.TypeAndValue {
+	return c.typeInfo.Types[expr]
+}
+
+func makeBoolFromIdent(ident *ast.Ident, tinfo *types.Info) types.TypeAndValue {
+	var b bool
+	if ident.Name == "true" {
+		b = true
+	} else if ident.Name == "false" {
+		b = false
+	} else {
+		log.Fatalf("givent identifier cannot be converted to a boolean => %s", ident.Name)
+	}
+
+	return types.TypeAndValue{
+		Type:  tinfo.ObjectOf(ident).Type(),
+		Value: constant.MakeBool(b),
+	}
+}
+
+func isIdentBool(ident *ast.Ident) bool {
+	return ident.Name == "true" || ident.Name == "false"
+}
+
+// CodeGen is the function that compiles the program to bytecode.
+func CodeGen(f *ast.File, tInfo *types.Info) (*bytes.Buffer, error) {
+	c := &codegen{
+		prog:     new(bytes.Buffer),
+		l:        []int{},
+		funcs:    map[string]*funcScope{},
+		typeInfo: tInfo,
+	}
+
+	var main *ast.FuncDecl
+	ast.Inspect(f, func(n ast.Node) bool {
+		switch t := n.(type) {
+		case *ast.FuncDecl:
+			if t.Name.Name == mainIdent {
+				main = t
+				return false
+			}
+		}
+		return true
+	})
+	if main == nil {
+		log.Fatal("could not find func main. did you forgot to declare it?")
+	}
+
+	c.resolveFuncDecls(f)
+	c.convertFuncDecl(main)
+
+	for _, decl := range f.Decls {
+		switch n := decl.(type) {
+		case *ast.FuncDecl:
+			if n.Name.Name != mainIdent {
+				c.convertFuncDecl(n)
+			}
+		}
+	}
+
+	c.writeJumps()
+
+	return c.prog, nil
+}
+
+func (c *codegen) resolveFuncDecls(f *ast.File) {
+	for _, decl := range f.Decls {
+		switch n := decl.(type) {
+		case *ast.FuncDecl:
+			if n.Name.Name != mainIdent {
+				c.newFunc(n)
+			}
+		}
+	}
+}
+
+func (c *codegen) writeJumps() {
+	b := c.prog.Bytes()
+	for i, op := range b {
+		j := i + 1
+		switch vm.Opcode(op) {
+		case vm.Ojmpifnot, vm.Ojmpif, vm.Ocall:
+			index := binary.LittleEndian.Uint16(b[j : j+2])
+			if int(index) > len(c.l) {
+				continue
+			}
+			offset := uint16(c.l[index] - i)
+			if offset < 0 {
+				log.Fatalf("new offset is negative, table list %v", c.l)
+			}
+			binary.LittleEndian.PutUint16(b[j:j+2], offset)
+		}
+	}
+}
diff --git a/pkg/vm/compiler/compiler.go b/pkg/vm/compiler/compiler.go
index eecd355a2..6aa7e8c9a 100644
--- a/pkg/vm/compiler/compiler.go
+++ b/pkg/vm/compiler/compiler.go
@@ -2,153 +2,44 @@ package compiler
 
 import (
 	"bytes"
+	"encoding/hex"
+	"errors"
+	"fmt"
 	"go/ast"
-	"go/constant"
 	"go/importer"
 	"go/parser"
 	"go/token"
 	"go/types"
 	"io"
+	"io/ioutil"
 	"log"
 	"os"
-	"reflect"
+	"strings"
+	"text/tabwriter"
 
 	"github.com/CityOfZion/neo-go/pkg/vm"
 )
 
-const (
-	outputExt = ".avm"
-	// Identifier off the entry point function.
-	mainIdent = "Main"
-)
+const fileExt = ".avm"
 
-// CallContext represents more details on function calls in the program.
-// It stores the position off where the call happend along with the
-// function it called. The compiler will store all function calls, so
-// it can update them later.
-type CallContext struct {
-	pos      int
-	funcName string
+// Options contains all the parameters that affect the behaviour of the compiler.
+type Options struct {
+	// The extension of the output file default set to .avm
+	Ext string
+
+	// The name of the output file.
+	Outfile string
+
+	// Debug will output an hex encoded string of the generated bytecode.
+	Debug bool
 }
 
-// A VarContext holds the info about the context of a variable in the program.
-type VarContext struct {
-	name  string
-	tinfo types.TypeAndValue
-	pos   int
-}
-
-func newVarContext(name string, tinfo types.TypeAndValue) *VarContext {
-	return &VarContext{
-		name:  name,
-		pos:   -1,
-		tinfo: tinfo,
-	}
-}
-
-// Compiler holds the output buffer of the compiled source.
-type Compiler struct {
-	// Output extension of the file. Default .avm.
-	OutputExt string
-
-	// scriptBuilder is responsible for all opcode writes.
-	sb *ScriptBuilder
-
-	// map with all function contexts across the program.
-	funcs map[string]*FuncContext
-
-	// list of function calls
-	funcCalls []CallContext
-
-	// struct with info about decls, types, uses, ..
-	typeInfo *types.Info
-}
-
-// New returns a new compiler ready to compile smartcontracts.
-func New() *Compiler {
-	return &Compiler{
-		OutputExt: outputExt,
-		sb:        &ScriptBuilder{buf: new(bytes.Buffer)},
-		funcs:     map[string]*FuncContext{},
-		funcCalls: []CallContext{},
-	}
-}
-
-// CompileSource will compile the source file into an avm format.
-func (c *Compiler) CompileSource(src string) error {
-	file, err := os.Open(src)
-	if err != nil {
-		return err
-	}
-	return c.Compile(file)
-}
-
-// LoadConst load a constant, if storeLocal is true it will store it on the position
-// of the VarContext.
-func (c *Compiler) loadConst(ctx *VarContext, storeLocal bool) {
-	switch t := ctx.tinfo.Type.(type) {
-	case *types.Basic:
-		switch t.Kind() {
-		case types.Int:
-			val, _ := constant.Int64Val(ctx.tinfo.Value)
-			c.sb.emitPushInt(val)
-		case types.String:
-			val := constant.StringVal(ctx.tinfo.Value)
-			c.sb.emitPushString(val)
-		case types.Bool, types.UntypedBool:
-			val := constant.BoolVal(ctx.tinfo.Value)
-			c.sb.emitPushBool(val)
-		}
-	default:
-		log.Fatalf("compiler don't know how to handle this => %v", ctx)
-	}
-
-	if storeLocal {
-		c.storeLocal(ctx)
-	}
-}
-
-// Load a local variable. The position of the VarContext is used to retrieve from
-// that position.
-func (c *Compiler) loadLocal(ctx *VarContext) {
-	pos := int64(ctx.pos)
-	if pos < 0 {
-		log.Fatalf("want to load local %v but got invalid position => %d <=", ctx, pos)
-	}
-
-	c.sb.emitPush(vm.OpFromAltStack)
-	c.sb.emitPush(vm.OpDup)
-	c.sb.emitPush(vm.OpToAltStack)
-
-	// push it's index on the stack
-	c.sb.emitPushInt(pos)
-	c.sb.emitPush(vm.OpPickItem)
-}
-
-// Store a local variable on the stack. The position of the VarContext is used
-// to store at that position.
-func (c *Compiler) storeLocal(vctx *VarContext) {
-	c.sb.emitPush(vm.OpFromAltStack)
-	c.sb.emitPush(vm.OpDup)
-	c.sb.emitPush(vm.OpToAltStack)
-
-	pos := int64(vctx.pos)
-	if pos < 0 {
-		log.Fatalf("want to store local %v but got invalid positionl => %d", vctx, pos)
-	}
-
-	c.sb.emitPushInt(pos)
-	c.sb.emitPushInt(2)
-	c.sb.emitPush(vm.OpRoll)
-	c.sb.emitPush(vm.OpSetItem)
-}
-
-// Compile will compile from r into an avm format.
-func (c *Compiler) Compile(r io.Reader) error {
+// Compile compiles a Go program into bytecode that can run on the NEO virtual machine.
+func Compile(input io.Reader, o *Options) ([]byte, error) {
 	fset := token.NewFileSet()
-	f, err := parser.ParseFile(fset, "", r, 0)
+	f, err := parser.ParseFile(fset, "", input, 0)
 	if err != nil {
-		return err
+		return nil, err
 	}
 
 	conf := types.Config{Importer: importer.Default()}
@@ -161,343 +52,67 @@ func (c *Compiler) Compile(r io.Reader) error {
 		Scopes:     make(map[ast.Node]*types.Scope),
 	}
 
-	c.typeInfo = typeInfo
-
 	// Typechecker
 	_, err = conf.Check("", fset, []*ast.File{f}, typeInfo)
 	if err != nil {
-		log.Fatal(err)
+		return nil, err
 	}
 
-	var main *ast.FuncDecl
-	ast.Inspect(f, func(n ast.Node) bool {
-		switch t := n.(type) {
-		case *ast.FuncDecl:
-			if t.Name.Name == mainIdent {
-				main = t
-				return false
-			}
+	buf, err := CodeGen(f, typeInfo)
+	if err != nil {
+		return nil, err
+	}
+
+	return buf.Bytes(), nil
+}
+
+// CompileAndSave will compile and save the file to disk.
+func CompileAndSave(src string, o *Options) error {
+	if len(o.Outfile) == 0 {
+		if !strings.HasSuffix(src, ".go") {
+			return errors.New("not a Go file")
 		}
-		return true
-	})
-	if main == nil {
-		log.Fatal("could not find func main. did you forgot to declare it?")
+		o.Outfile = strings.TrimSuffix(src, ".go")
+	}
+	if len(o.Ext) == 0 {
+		o.Ext = fileExt
+	}
+	b, err := ioutil.ReadFile(src)
+	if err != nil {
+		return err
+	}
+	b, err = Compile(bytes.NewReader(b), o)
+	if err != nil {
+		return err
+	}
+	if o.Debug {
+		log.Println(hex.EncodeToString(b))
 	}
 
-	c.resolveFuncDecls(f)
-	c.convertFuncDecl(main)
+	out := fmt.Sprintf("%s.%s", o.Outfile, o.Ext)
+	return ioutil.WriteFile(out, b, os.ModePerm)
+}
 
-	// Start building all declarations
-	for _, decl := range f.Decls {
-		switch t := decl.(type) {
-		case *ast.GenDecl:
-		case *ast.FuncDecl:
-			if t.Name.Name != mainIdent {
-				c.convertFuncDecl(t)
-			}
-		}
+// DumpOpcode compiles the program and dumps the opcode in a user friendly format.
+func DumpOpcode(src string) error {
+	b, err := ioutil.ReadFile(src)
+	if err != nil {
+		return err
+	}
+	b, err = Compile(bytes.NewReader(b), &Options{})
+	if err != nil {
+		return err
 	}
 
-	// update all local function calls.
-	c.updateFuncCalls()
-
+	w := tabwriter.NewWriter(os.Stdout, 0, 0, 4, ' ', 0)
+	fmt.Fprintln(w, "INDEX\tOPCODE\tDESC\t")
+	for i := 0; i < len(b); i++ {
+		fmt.Fprintf(w, "%d\t0x%2x\t%s\t\n", i, b[i], vm.Opcode(b[i]))
+	}
+	w.Flush()
 	return nil
 }
 
-// updateFuncCalls will update all local function calls that occured the program.
-func (c *Compiler) updateFuncCalls() {
-	for _, ctx := range c.funcCalls {
-		fun, ok := c.funcs[ctx.funcName]
-		if !ok {
-			log.Fatalf("could not resolve function %s", ctx.funcName)
-		}
-		// pos is the position of the call op, we need to add 1 to get the
-		// start of the label.
-		// for calculating the correct offset we need to subtract the target label
-		// with the position the call occured.
-		offset := fun.label - int16(ctx.pos)
-		c.sb.updatePushCall(ctx.pos+1, offset)
-	}
-}
-
-func (c *Compiler) resolveFuncDecls(f *ast.File) {
-	for _, decl := range f.Decls {
-		switch t := decl.(type) {
-		case *ast.GenDecl:
-		case *ast.FuncDecl:
-			if t.Name.Name != mainIdent {
-				c.funcs[t.Name.Name] = newFuncContext(t, 0)
-			}
-		}
-	}
-}
-
-func (c *Compiler) convertFuncDecl(decl *ast.FuncDecl) {
-	ctx := newFuncContext(decl, c.currentPos())
-	c.funcs[ctx.name] = ctx
-
-	// We need to write the the total stack size of the function first.
-	// That size is the number of arguments + body operations  that will be
-	// pushed on the stack
-	c.sb.emitPushInt(ctx.numStackOps())
-	c.sb.emitPush(vm.OpNewArray)
-	c.sb.emitPush(vm.OpToAltStack)
-
-	// Load the arguments into scope.
-	for _, arg := range decl.Type.Params.List {
-		name := arg.Names[0].Name
-		ctx.args[name] = true
-		vctx := ctx.newConst(name, c.getTypeInfo(arg.Type), true)
-		c.storeLocal(vctx)
-	}
-
-	for _, stmt := range decl.Body.List {
-		c.convertStmt(ctx, stmt)
-	}
-}
-
-func (c *Compiler) convertStmt(fctx *FuncContext, stmt ast.Stmt) {
-	switch t := stmt.(type) {
-	case *ast.AssignStmt:
-		for i := 0; i < len(t.Lhs); i++ {
-			lhs := t.Lhs[i].(*ast.Ident)
-
-			switch rhs := t.Rhs[i].(type) {
-			case *ast.BasicLit:
-				vctx := fctx.newConst(lhs.Name, c.getTypeInfo(t.Rhs[i]), true)
-				c.loadConst(vctx, true)
-
-			case *ast.CompositeLit:
-				// Write constants in reverse order on the stack.
-				n := len(rhs.Elts)
-				for i := n - 1; i >= 0; i-- {
-					vctx := fctx.newConst("", c.getTypeInfo(rhs.Elts[i]), false)
-					c.loadConst(vctx, false)
-				}
-
-				c.sb.emitPushInt(int64(n))
-				c.sb.emitPush(vm.OpPack)
-
-				vctx := fctx.newConst(lhs.Name, c.getTypeInfo(rhs), true)
-				c.storeLocal(vctx)
-
-			case *ast.Ident:
-				if isIdentBool(rhs) {
-					vctx := fctx.newConst(lhs.Name, makeBoolFromIdent(rhs, c.typeInfo), true)
-					c.loadConst(vctx, true)
-					continue
-				}
-
-				knownCtx := fctx.getContext(rhs.Name)
-				c.loadLocal(knownCtx)
-				newCtx := fctx.newConst(lhs.Name, c.getTypeInfo(rhs), true)
-				c.storeLocal(newCtx)
-
-			default:
-				c.convertExpr(fctx, t.Rhs[i])
-				vctx := fctx.newConst(lhs.Name, c.getTypeInfo(t.Rhs[i]), true)
-				c.storeLocal(vctx)
-			}
-		}
-
-	//Due to the design of the orginal VM, multiple return are not supported.
-	case *ast.ReturnStmt:
-		if len(t.Results) > 1 {
-			log.Fatal("multiple returns not supported.")
-		}
-
-		c.sb.emitPush(vm.OpJMP)
-		c.sb.emitPush(vm.OpCode(0x03))
-		c.sb.emitPush(vm.OpPush0)
-
-		c.convertExpr(fctx, t.Results[0])
-
-		c.sb.emitPush(vm.OpNOP)
-		c.sb.emitPush(vm.OpFromAltStack)
-		c.sb.emitPush(vm.OpDrop)
-		c.sb.emitPush(vm.OpRET)
-
-	// TODO: this needs a rewrite ASAP.
-	case *ast.IfStmt:
-		c.convertExpr(fctx, t.Cond)
-
-		binExpr, ok := t.Cond.(*ast.BinaryExpr)
-		if ok && binExpr.Op != token.LAND && binExpr.Op != token.LOR {
-			// use a placeholder for the label.
-			c.sb.emitJump(vm.OpJMPIFNOT, int16(0))
-			// track our offset to update later subtract sizeOf int16.
-			offset := int(c.currentPos()) - 2
-
-			defer func(offset int) {
-				jumpTo := c.currentPos() + 1 - int16(offset)
-				c.sb.updateJmpLabel(jumpTo, offset)
-			}(offset)
-		}
-
-		labelBeforeBlock := c.currentPos()
-		// Process the block.
-		for _, stmt := range t.Body.List {
-			c.convertStmt(fctx, stmt)
-		}
-
-		// if there are any labels we need to update.
-		if len(fctx.jumpLabels) > 0 {
-			for _, label := range fctx.jumpLabels {
-				var pos int16
-				if label.op == vm.OpJMPIF {
-					pos = labelBeforeBlock + 1
-				} else {
-					pos = c.currentPos() + 1
-				}
-				jumpTo := pos - int16(label.offset)
-				c.sb.updateJmpLabel(jumpTo, label.offset)
-			}
-			fctx.jumpLabels = []jumpLabel{}
-		}
-
-	default:
-		log.Fatalf("compiler has not implemented this statement => %v", reflect.TypeOf(t))
-	}
-}
-
-func (c *Compiler) convertExpr(fctx *FuncContext, expr ast.Expr) {
-	switch t := expr.(type) {
-	case *ast.BasicLit:
-		vctx := fctx.newConst("", c.getTypeInfo(t), false)
-		c.loadConst(vctx, false)
-
-	case *ast.Ident:
-		if isIdentBool(t) {
-			vctx := fctx.newConst(t.Name, makeBoolFromIdent(t, c.typeInfo), false)
-			c.loadConst(vctx, false)
-			return
-		}
-		if fctx.isArgument(t.Name) {
-			vctx := fctx.getContext(t.Name)
-			c.loadLocal(vctx)
-			return
-		}
-		vctx := fctx.getContext(t.Name)
-		c.loadLocal(vctx)
-
-	case *ast.CallExpr:
-		fun := t.Fun.(*ast.Ident)
-		fctx, ok := c.funcs[fun.Name]
-		if !ok {
-			log.Fatalf("could not resolve func %s", fun.Name)
-		}
-
-		// handle the passed arguments.
-		for _, arg := range t.Args {
-			vctx := fctx.newConst("", c.getTypeInfo(arg), false)
-			c.loadLocal(vctx)
-		}
-
-		// c# compiler adds a NOP (0x61) before every function call. Dont think its relevant
-		// and we could easily removed it, but to be consistent with the original compiler I
-		// will put them in. ^^
-		c.sb.emitPush(vm.OpNOP)
-
-		c.funcCalls = append(c.funcCalls, CallContext{int(c.currentPos()), fun.Name})
-		c.sb.emitPushCall(0) // placeholder, update later.
-
-	case *ast.BinaryExpr:
-		if t.Op == token.LAND || t.Op == token.LOR {
-			c.convertExpr(fctx, t.X)
-
-			opJMP := vm.OpJMPIFNOT
-			if t.Op == token.LOR {
-				opJMP = vm.OpJMPIF
-			}
-
-			if e, ok := t.X.(*ast.BinaryExpr); ok && e.Op != token.LAND && e.Op != token.LOR {
-				c.sb.emitJump(opJMP, int16(0))
-				fctx.addJump(opJMP, int(c.currentPos())-2)
-			}
-
-			c.convertExpr(fctx, t.Y)
-			c.sb.emitJump(vm.OpJMPIFNOT, int16(0))
-			fctx.addJump(vm.OpJMPIFNOT, int(c.currentPos())-2)
-			c.convertToken(t.Op)
-			return
-		}
-
-		// The AST package resolves all basic literals for us. If the typeinfo.Value is not nil
-		// we know that the bin expr is resolved and needs no further action.
-		// e.g. x := 2 + 2 + 2 will be resolved to 6.
-		if tinfo := c.getTypeInfo(t); tinfo.Value != nil {
-			vctx := fctx.newConst("", tinfo, false)
-			c.loadConst(vctx, false)
-			return
-		}
-
-		c.convertExpr(fctx, t.X)
-		c.convertExpr(fctx, t.Y)
-		c.convertToken(t.Op)
-
-	default:
-		log.Fatalf("compiler has not implemented this expr => %v", reflect.TypeOf(t))
-	}
-}
-
-func (c *Compiler) convertToken(tok token.Token) {
-	switch tok {
-	case token.ADD:
-		c.sb.emitPush(vm.OpAdd)
-	case token.SUB:
-		c.sb.emitPush(vm.OpSub)
-	case token.MUL:
-		c.sb.emitPush(vm.OpMul)
-	case token.QUO:
-		c.sb.emitPush(vm.OpDiv)
-	case token.LSS:
-		c.sb.emitPush(vm.OpLT)
-	case token.LEQ:
-		c.sb.emitPush(vm.OpLTE)
-	case token.GTR:
-		c.sb.emitPush(vm.OpGT)
-	case token.GEQ:
-		c.sb.emitPush(vm.OpGTE)
-	}
-}
-
-// getTypeInfo return TypeAndValue for the given expression. If it could not resolve
-// the type value and type will be NIL.
-func (c *Compiler) getTypeInfo(expr ast.Expr) types.TypeAndValue {
-	return c.typeInfo.Types[expr]
-}
-
-// currentPos return the current position (address) of the latest opcode.
-func (c *Compiler) currentPos() int16 {
-	return int16(c.sb.buf.Len())
-}
-
-// Buffer returns the buffer of the builder as a io.Reader.
-func (c *Compiler) Buffer() *bytes.Buffer {
-	return c.sb.buf
-}
-
-// DumpOpcode dumps the current buffer, formatted with index, hex and opcode.
-func (c *Compiler) DumpOpcode() {
-	c.sb.dumpOpcode()
-}
-
-func makeBoolFromIdent(ident *ast.Ident, tinfo *types.Info) types.TypeAndValue {
-	var b bool
-	if ident.Name == "true" {
-		b = true
-	} else if ident.Name == "false" {
-		b = false
-	} else {
-		log.Fatalf("givent identifier cannot be converted to a boolean => %s", ident.Name)
-	}
-
-	return types.TypeAndValue{
-		Type:  tinfo.ObjectOf(ident).Type(),
-		Value: constant.MakeBool(b),
-	}
-}
-
-func isIdentBool(ident *ast.Ident) bool {
-	return ident.Name == "true" || ident.Name == "false"
+func init() {
+	log.SetFlags(0)
 }
diff --git a/pkg/vm/compiler/emit.go b/pkg/vm/compiler/emit.go
new file mode 100644
index 000000000..c0cfb738e
--- /dev/null
+++ b/pkg/vm/compiler/emit.go
@@ -0,0 +1,101 @@
+package compiler
+
+import (
+	"bytes"
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"math/big"
+
+	"github.com/CityOfZion/neo-go/pkg/util"
+	"github.com/CityOfZion/neo-go/pkg/vm"
+)
+
+func emit(w *bytes.Buffer, op vm.Opcode, b []byte) error {
+	if err := w.WriteByte(byte(op)); err != nil {
+		return err
+	}
+	_, err := w.Write(b)
+	return err
+}
+
+func emitOpcode(w *bytes.Buffer, op vm.Opcode) error {
+	return w.WriteByte(byte(op))
+}
+
+func emitBool(w *bytes.Buffer, ok bool) error {
+	if ok {
+		return emitOpcode(w, vm.Opusht)
+	}
+	return emitOpcode(w, vm.Opushf)
+}
+
+func emitInt(w *bytes.Buffer, i int64) error {
+	if i == -1 {
+		return emitOpcode(w, vm.Opushm1)
+	}
+	if i == 0 {
+		return emitOpcode(w, vm.Opushf)
+	}
+	if i > 0 && i < 16 {
+		val := vm.Opcode((int(vm.Opush1) - 1 + int(i)))
+		return emitOpcode(w, val)
+	}
+
+	bInt := big.NewInt(i)
+	val := util.ToArrayReverse(bInt.Bytes())
+	return emitBytes(w, val)
+}
+
+func emitString(w *bytes.Buffer, s string) error {
+	return emitBytes(w, []byte(s))
+}
+
+func emitBytes(w *bytes.Buffer, b []byte) error {
+	var (
+		err error
+		n   = len(b)
+	)
+
+	if n == 0 {
+		return errors.New("cannot emit 0 bytes")
+	}
+	if n <= int(vm.Opushbytes75) {
+		return emit(w, vm.Opcode(n), b)
+	} else if n < 0x100 {
+		err = emit(w, vm.Opushdata1, []byte{byte(n)})
+	} else if n < 0x10000 {
+		buf := make([]byte, 2)
+		binary.LittleEndian.PutUint16(buf, uint16(n))
+		err = emit(w, vm.Opushdata2, buf)
+	} else {
+		buf := make([]byte, 4)
+		binary.LittleEndian.PutUint32(buf, uint32(n))
+		err = emit(w, vm.Opushdata4, buf)
+	}
+	if err != nil {
+		return err
+	}
+	_, err = w.Write(b)
+	return err
+}
+
+func emitCall(w *bytes.Buffer, op vm.Opcode, label int16) error {
+	return emitJmp(w, op, label)
+}
+
+func emitJmp(w *bytes.Buffer, op vm.Opcode, label int16) error {
+	if !isOpcodeJmp(op) {
+		return fmt.Errorf("opcode %s is not a jump or call type", op)
+	}
+	buf := make([]byte, 2)
+	binary.LittleEndian.PutUint16(buf, uint16(label))
+	return emit(w, op, buf)
+}
+
+func isOpcodeJmp(op vm.Opcode) bool {
+	if op == vm.Ojmp || op == vm.Ojmpifnot || op == vm.Ojmpif || op == vm.Ocall {
+		return true
+	}
+	return false
+}
diff --git a/pkg/vm/compiler/func_context.go b/pkg/vm/compiler/func_context.go
deleted file mode 100644
index e00e6dcc4..000000000
--- a/pkg/vm/compiler/func_context.go
+++ /dev/null
@@ -1,96 +0,0 @@
-package compiler
-
-import (
-	"go/ast"
-	"go/types"
-	"log"
-
-	"github.com/CityOfZion/neo-go/pkg/vm"
-)
-
-type jumpLabel struct {
-	offset int
-	op     vm.OpCode
-}
-
-// A FuncContext represents details about a function in the program along withs its variables.
-type FuncContext struct {
-	// The declaration tree of this function.
-	decl *ast.FuncDecl
-	// Identifier (name of the function in the program).
-	name string
-	// The scope of the function.
-	scope map[string]*VarContext
-	// Arguments of the function.
-	args map[string]bool
-	// Address (label) where the compiler can find this function when someone calls it.
-	label int16
-	// Counter for stored local variables.
-	i int
-	// This needs refactor along with the (if stmt)
-	jumpLabels []jumpLabel
-}
-
-func (f *FuncContext) addJump(op vm.OpCode, offset int) {
-	f.jumpLabels = append(f.jumpLabels, jumpLabel{offset, op})
-}
-
-func newFuncContext(decl *ast.FuncDecl, label int16) *FuncContext {
-	return &FuncContext{
-		decl:       decl,
-		label:      int16(label),
-		name:       decl.Name.Name,
-		scope:      map[string]*VarContext{},
-		args:       map[string]bool{},
-		jumpLabels: []jumpLabel{},
-	}
-}
-
-func (f *FuncContext) newConst(name string, t types.TypeAndValue, needStore bool) *VarContext {
-	ctx := &VarContext{
-		name:  name,
-		tinfo: t,
-	}
-	if needStore {
-		f.storeContext(ctx)
-	}
-	return ctx
-}
-
-func (f *FuncContext) numStackOps() int64 {
-	ops := 0
-	ast.Inspect(f.decl, func(n ast.Node) bool {
-		switch n.(type) {
-		case *ast.AssignStmt, *ast.ReturnStmt, *ast.IfStmt:
-			ops++
-		}
-		return true
-	})
-
-	numArgs := len(f.decl.Type.Params.List)
-	return int64(ops + numArgs)
-}
-
-func (f *FuncContext) storeContext(ctx *VarContext) {
-	ctx.pos = f.i
-	f.scope[ctx.name] = ctx
-	f.i++
-}
-
-func (f *FuncContext) getContext(name string) *VarContext {
-	ctx, ok := f.scope[name]
-	if !ok {
-		log.Fatalf("could not resolve variable %s", name)
-	}
-	return ctx
-}
-
-func (f *FuncContext) isRegistered(ctx *VarContext) bool {
-	_, ok := f.scope[ctx.name]
-	return ok
-}
-
-func (f *FuncContext) isArgument(name string) bool {
-	_, ok := f.args[name]
-	return ok
-}
diff --git a/pkg/vm/compiler/func_scope.go b/pkg/vm/compiler/func_scope.go
new file mode 100644
index 000000000..c545e3273
--- /dev/null
+++ b/pkg/vm/compiler/func_scope.go
@@ -0,0 +1,89 @@
+package compiler
+
+import (
+	"go/ast"
+	"log"
+)
+
+// A funcScope represents a scope within the function context.
+// It holds al the local variables along with the initialized struct positions.
+type funcScope struct {
+	// function identifier
+	name string
+
+	// The declaration of the function in the AST
+	decl *ast.FuncDecl
+
+	// program label of the function
+	label int
+
+	// local scope of the function
+	scope map[string]int
+
+	// mapping of structs positions with their scope
+	structs map[int]*structScope
+
+	// local variable counter
+	i int
+}
+
+func newFuncScope(decl *ast.FuncDecl, label int) *funcScope {
+	return &funcScope{
+		name:    decl.Name.Name,
+		decl:    decl,
+		label:   label,
+		scope:   map[string]int{},
+		structs: map[int]*structScope{},
+		i:       -1,
+	}
+}
+
+func (c *funcScope) stackSize() int64 {
+	size := 0
+	ast.Inspect(c.decl, func(n ast.Node) bool {
+		switch n.(type) {
+		case *ast.AssignStmt, *ast.ReturnStmt, *ast.IfStmt:
+			size++
+		}
+		return true
+	})
+
+	numArgs := len(c.decl.Type.Params.List)
+	// Also take care of struct methods recv: e.g. (t Token).Foo().
+	if c.decl.Recv != nil {
+		numArgs += len(c.decl.Recv.List)
+	}
+	return int64(size + numArgs)
+}
+
+func (c *funcScope) newStruct() *structScope {
+	strct := newStructScope()
+	c.structs[len(c.scope)] = strct
+	return strct
+}
+
+func (c *funcScope) loadStruct(name string) *structScope {
+	l := c.loadLocal(name)
+	strct, ok := c.structs[l]
+	if !ok {
+		log.Fatalf("could not resolve struct %s", name)
+	}
+	return strct
+}
+
+// newLocal creates a new local variable into the scope of the function.
+func (c *funcScope) newLocal(name string) int {
+	c.i++
+	c.scope[name] = c.i
+	return c.i
+}
+
+// loadLocal loads the position of a local variable inside the scope of the function.
+func (c *funcScope) loadLocal(name string) int {
+	i, ok := c.scope[name]
+	if !ok {
+		// should emit a compiler warning.
+		return c.newLocal(name)
+	}
+	return i
+}
diff --git a/pkg/vm/compiler/script_builder.go b/pkg/vm/compiler/script_builder.go
deleted file mode 100644
index 317e2582a..000000000
--- a/pkg/vm/compiler/script_builder.go
+++ /dev/null
@@ -1,152 +0,0 @@
-package compiler
-
-import (
-	"bytes"
-	"encoding/binary"
-	"errors"
-	"fmt"
-	"math/big"
-	"os"
-	"text/tabwriter"
-
-	"github.com/CityOfZion/neo-go/pkg/util"
-	"github.com/CityOfZion/neo-go/pkg/vm"
-)
-
-// ScriptBuilder generates bytecode and will write all
-// generated bytecode into its internal buffer.
-type ScriptBuilder struct {
-	buf *bytes.Buffer
-}
-
-func (sb *ScriptBuilder) emit(op vm.OpCode, b []byte) error {
-	if err := sb.buf.WriteByte(byte(op)); err != nil {
-		return err
-	}
-	_, err := sb.buf.Write(b)
-	return err
-}
-
-func (sb *ScriptBuilder) emitPush(op vm.OpCode) error {
-	return sb.buf.WriteByte(byte(op))
-}
-
-func (sb *ScriptBuilder) emitPushBool(b bool) error {
-	if b {
-		return sb.emitPush(vm.OpPushT)
-	}
-	return sb.emitPush(vm.OpPushF)
-}
-
-func (sb *ScriptBuilder) emitPushInt(i int64) error {
-	if i == -1 {
-		return sb.emitPush(vm.OpPushM1)
-	}
-	if i == 0 {
-		return sb.emitPush(vm.OpPushF)
-	}
-	if i > 0 && i < 16 {
-		val := vm.OpCode((int(vm.OpPush1) - 1 + int(i)))
-		return sb.emitPush(val)
-	}
-
-	bInt := big.NewInt(i)
-	val := util.ToArrayReverse(bInt.Bytes())
-	return sb.emitPushArray(val)
-}
-
-func (sb *ScriptBuilder) emitPushArray(b []byte) error {
-	var (
-		err error
-		n   = len(b)
-	)
-
-	if n == 0 {
-		return errors.New("0 bytes given in pushArray")
-	}
-	if n <= int(vm.OpPushBytes75) {
-		return sb.emit(vm.OpCode(n), b)
-	} else if n < 0x100 {
-		err = sb.emit(vm.OpPushData1, []byte{byte(n)})
-	} else if n < 0x10000 {
-		buf := make([]byte, 2)
-		binary.LittleEndian.PutUint16(buf, uint16(n))
-		err = sb.emit(vm.OpPushData2, buf)
-	} else {
-		buf := make([]byte, 4)
-		binary.LittleEndian.PutUint32(buf, uint32(n))
-		err = sb.emit(vm.OpPushData4, buf)
-	}
-	if err != nil {
-		return err
-	}
-	_, err = sb.buf.Write(b)
-	return err
-}
-
-func (sb *ScriptBuilder) emitPushString(str string) error {
-	return sb.emitPushArray([]byte(str))
-}
-
-func (sb *ScriptBuilder) emitSysCall(api string) error {
-	lenAPI := len(api)
-	if lenAPI == 0 {
-		return errors.New("syscall argument cant be 0")
-	}
-	if lenAPI > 252 {
-		return fmt.Errorf("invalid syscall argument: %s", api)
-	}
-
-	bapi := []byte(api)
-	args := make([]byte, lenAPI+1)
-	args[0] = byte(lenAPI)
-	copy(args, bapi[1:])
-	return sb.emit(vm.OpSysCall, args)
-}
-
-func (sb *ScriptBuilder) emitPushCall(offset int16) error {
-	buf := new(bytes.Buffer)
-	binary.Write(buf, binary.LittleEndian, offset)
-	return sb.emit(vm.OpCall, buf.Bytes())
-}
-
-func (sb *ScriptBuilder) emitJump(op vm.OpCode, offset int16) error {
-	if op != vm.OpJMP && op != vm.OpJMPIF && op != vm.OpJMPIFNOT && op != vm.OpCall {
-		return fmt.Errorf("invalid jump opcode: %v", op)
-	}
-	buf := make([]byte, 2)
-	binary.LittleEndian.PutUint16(buf, uint16(offset))
-	return sb.emit(op, buf)
-}
-
-func (sb *ScriptBuilder) updateJmpLabel(label int16, offset int) error {
-	sizeOfInt16 := 2
-	if sizeOfInt16+offset >= sb.buf.Len() {
-		return fmt.Errorf("cannot update label at offset %d", offset)
-	}
-
-	b := make([]byte, sizeOfInt16)
-	binary.LittleEndian.PutUint16(b, uint16(label))
-	buf := sb.buf.Bytes()
-	copy(buf[offset:offset+sizeOfInt16], b)
-	return nil
-}
-
-func (sb *ScriptBuilder) updatePushCall(offset int, label int16) {
-	b := new(bytes.Buffer)
-	binary.Write(b, binary.LittleEndian, label)
-
-	buf := sb.buf.Bytes()
-	copy(buf[offset:offset+2], b.Bytes())
-}
-
-func (sb *ScriptBuilder) dumpOpcode() {
-	w := tabwriter.NewWriter(os.Stdout, 0, 0, 4, ' ', 0)
-	buf := sb.buf.Bytes()
-
-	fmt.Fprintln(w, "INDEX\tOPCODE\tDESC")
-	for i := 0; i < len(buf); i++ {
-		fmt.Fprintf(w, "%d\t0x%2x\t%s\n", i, buf[i], vm.OpCode(buf[i]))
-	}
-	w.Flush()
-}
diff --git a/pkg/vm/compiler/script_builder_test.go b/pkg/vm/compiler/script_builder_test.go
deleted file mode 100644
index 9e22cbd04..000000000
--- a/pkg/vm/compiler/script_builder_test.go
+++ /dev/null
@@ -1,104 +0,0 @@
-package compiler
-
-import (
-	"bytes"
-	"math/big"
-	"testing"
-
-	"github.com/CityOfZion/neo-go/pkg/util"
-	"github.com/CityOfZion/neo-go/pkg/vm"
-)
-
-func TestEmitPush(t *testing.T) {
-	sb := &ScriptBuilder{buf: new(bytes.Buffer)}
-
-	if err := sb.emitPush(vm.OpPush1); err != nil {
-		t.Fatal(err)
-	}
-	if sb.buf.Len() != 1 {
-		t.Fatalf("expect buffer len of 1 got %d", sb.buf.Len())
-	}
-}
-func TestEmitPushIntNeg(t *testing.T) {
-	sb := &ScriptBuilder{buf: new(bytes.Buffer)}
-	val := -1
-	if err := sb.emitPushInt(int64(val)); err != nil {
-		t.Fatal(err)
-	}
-	if want, have := vm.OpPushM1, vm.OpCode(sb.buf.Bytes()[0]); want != have {
-		t.Fatalf("expected %v got %v", want, have)
-	}
-}
-
-func TestEmitPushInt0(t *testing.T) {
-	sb := &ScriptBuilder{buf: new(bytes.Buffer)}
-	val := 0
-	if err := sb.emitPushInt(int64(val)); err != nil {
-		t.Fatal(err)
-	}
-	if want, have := vm.OpPushF, vm.OpCode(sb.buf.Bytes()[0]); want != have {
-		t.Fatalf("expected %v got %v", want, have)
-	}
-}
-
-func TestEmitPushInt1(t *testing.T) {
-	sb := &ScriptBuilder{buf: new(bytes.Buffer)}
-	val := 1
-	if err := sb.emitPushInt(int64(val)); err != nil {
-		t.Fatal(err)
-	}
-	if want, have := vm.OpPush1, vm.OpCode(sb.buf.Bytes()[0]); want != have {
-		t.Fatalf("expected %v got %v", want, have)
-	}
-}
-
-func TestEmitPushInt100(t *testing.T) {
-	x := 100
-	bigx := big.NewInt(int64(x))
-	t.Log(bigx.Bytes())
-
-	sb := &ScriptBuilder{buf: new(bytes.Buffer)}
-	val := 100
-	if err := sb.emitPushInt(int64(val)); err != nil {
-		t.Fatal(err)
-	}
-	// len = 1
-	if want, have := byte(0x01), byte(sb.buf.Bytes()[0]); want != have {
-		t.Fatalf("expected %v got %v", want, have)
-	}
-	if want, have := byte(0x64), byte(sb.buf.Bytes()[1]); want != have {
-		t.Fatalf("expected %v got %v", want, have)
-	}
-}
-
-func TestEmitPush1000(t *testing.T) {
-	sb := &ScriptBuilder{buf: new(bytes.Buffer)}
-	val := 1000
-	if err := sb.emitPushInt(int64(val)); err != nil {
-		t.Fatal(err)
-	}
-	bInt := big.NewInt(int64(val))
-	if want, have := byte(len(bInt.Bytes())), byte(sb.buf.Bytes()[0]); want != have {
-		t.Fatalf("expected %v got %v", want, have)
-	}
-	want := util.ToArrayReverse(bInt.Bytes()) // reverse
-	have := sb.buf.Bytes()[1:]
-	if bytes.Compare(want, have) != 0 {
-		t.Fatalf("expected %v got %v", want, have)
-	}
-}
-
-func TestEmitPushString(t *testing.T) {
-	sb := &ScriptBuilder{buf: new(bytes.Buffer)}
-	str := "anthdm"
-	if err := sb.emitPushString(str); err != nil {
-		t.Fatal(err)
-	}
-	if want, have := byte(len(str)), sb.buf.Bytes()[0]; want != have {
-		t.Fatalf("expected %v got %v", want, have)
-	}
-	want, have := []byte(str), sb.buf.Bytes()[1:]
-	if bytes.Compare(want, have) != 0 {
-		t.Fatalf("expected %v got %v", want, have)
-	}
-}
diff --git a/pkg/vm/compiler/struct_scope.go b/pkg/vm/compiler/struct_scope.go
new file mode 100644
index 000000000..8bf71fea7
--- /dev/null
+++ b/pkg/vm/compiler/struct_scope.go
@@ -0,0 +1,51 @@
+package compiler
+
+import (
+	"go/ast"
+	"go/types"
+	"log"
+)
+
+// A structScope holds the positions for it's fields. Struct fields have different
+// positions then local variables in any scope.
+type structScope struct {
+	// identifier of the initialized struct in the program.
+	name string
+
+	// a mapping of field identifier and its position.
+	fields map[string]int
+}
+
+func newStructScope() *structScope {
+	return &structScope{
+		fields: map[string]int{},
+	}
+}
+
+func (s *structScope) newField(name string) int {
+	i := len(s.fields)
+	s.fields[name] = i
+	return i
+}
+
+func (s *structScope) loadField(name string) int {
+	i, ok := s.fields[name]
+	if !ok {
+		log.Fatalf("could not resolve field name %s for struct %s", name, s.name)
+	}
+	return i
+}
+
+func (s *structScope) initializeFields(ident *ast.Ident, tInfo *types.Info) {
+	def, ok := tInfo.Defs[ident]
+	if !ok {
+		log.Fatalf("could not initialize fields of %s: definitions not found in typeinfo", ident.Name)
+	}
+	t, ok := def.Type().Underlying().(*types.Struct)
+	if !ok {
+		log.Fatalf("%s is not of type struct", ident.Name)
+	}
+	for i := 0; i < t.NumFields(); i++ {
+		s.newField(t.Field(i).Name())
+	}
+}
diff --git a/pkg/vm/compiler/tests/array_test.go b/pkg/vm/compiler/tests/array_test.go
new file mode 100644
index 000000000..2b6c19883
--- /dev/null
+++ b/pkg/vm/compiler/tests/array_test.go
@@ -0,0 +1,26 @@
+package compiler_test
+
+var arrayTestCases = []testCase{
+	{
+		"assign int array",
+		`
+		package foo
+		func Main() []int {
+			x := []int{1, 2, 3}
+			return x
+		}
+		`,
+		"52c56b53525153c16c766b00527ac46203006c766b00c3616c7566",
+	},
+	{
+		"assign string array",
+		`
+		package foo
+		func Main() []string {
+			x := []string{"foo", "bar", "foobar"}
+			return x
+		}
+		`,
+		"52c56b06666f6f6261720362617203666f6f53c16c766b00527ac46203006c766b00c3616c7566",
+	},
+}
diff --git a/pkg/vm/compiler/tests/assign_test.go b/pkg/vm/compiler/tests/assign_test.go
new file mode 100644
index 000000000..7fa71d387
--- /dev/null
+++ b/pkg/vm/compiler/tests/assign_test.go
@@ -0,0 +1,31 @@
+package compiler_test
+
+var assignTestCases = []testCase{
+	{
+		"chain define",
+		`
+		package foo
+		func Main() int {
+			x := 4
+			y := x
+			z := y
+			foo := z
+			bar := foo
+			return bar
+		}
+		`,
+		"56c56b546c766b00527ac46c766b00c36c766b51527ac46c766b51c36c766b52527ac46c766b52c36c766b53527ac46c766b53c36c766b54527ac46203006c766b54c3616c7566",
+	},
+	{
+		"simple assign",
+		`
+		package foo
+		func Main() int {
+			x := 4
+			x = 8
+			return x
+		}
+		`,
+		"53c56b546c766b00527ac4586c766b00527ac46203006c766b00c3616c7566",
+	},
+}
diff --git a/pkg/vm/compiler/tests/bool_test.go b/pkg/vm/compiler/tests/bool_test.go
new file mode 100644
index 000000000..90d09f9d9
--- /dev/null
+++ b/pkg/vm/compiler/tests/bool_test.go
@@ -0,0 +1,15 @@
+package compiler_test
+
+var boolTestCases = []testCase{
+	{
+		"bool assign",
+		`
+		package foo
+		func Main() bool {
+			x := true
+			return x
+		}
+		`,
+		"52c56b516c766b00527ac46203006c766b00c3616c7566",
+	},
+}
diff --git a/pkg/vm/compiler/tests/compiler_test.go b/pkg/vm/compiler/tests/compiler_test.go
index 4f600b5ad..d3b55d800 100644
--- a/pkg/vm/compiler/tests/compiler_test.go
+++ b/pkg/vm/compiler/tests/compiler_test.go
@@ -21,14 +21,18 @@ type testCase struct {
 
 func TestAllCases(t *testing.T) {
 	testCases := []testCase{}
+	testCases = append(testCases, assignTestCases...)
+	testCases = append(testCases, arrayTestCases...)
+	testCases = append(testCases, functionCallTestCases...)
+	testCases = append(testCases, boolTestCases...)
 	testCases = append(testCases, stringTestCases...)
 	testCases = append(testCases, binaryExprTestCases...)
+	testCases = append(testCases, structTestCases...)
 	testCases = append(testCases, ifStatementTestCases...)
-	testCases = append(testCases, functionCallTestCases...)
 
 	for _, tc := range testCases {
-		c := compiler.New()
-		if err := c.Compile(strings.NewReader(tc.src)); err != nil {
+		b, err := compiler.Compile(strings.NewReader(tc.src), &compiler.Options{})
+		if err != nil {
 			t.Fatal(err)
 		}
 
@@ -37,10 +41,10 @@ func TestAllCases(t *testing.T) {
 			t.Fatal(err)
 		}
 
-		if bytes.Compare(c.Buffer().Bytes(), expectedResult) != 0 {
-			t.Log(hex.EncodeToString(c.Buffer().Bytes()))
+		if bytes.Compare(b, expectedResult) != 0 {
+			t.Log(hex.EncodeToString(b))
 			want, _ := hex.DecodeString(tc.result)
-			dumpOpCodeSideBySide(c.Buffer().Bytes(), want)
+			dumpOpCodeSideBySide(b, want)
 			t.Fatalf("compiling %s failed", tc.name)
 		}
 	}
@@ -59,7 +63,7 @@ func dumpOpCodeSideBySide(have, want []byte) {
 			diff = "<<"
 		}
 		fmt.Fprintf(w, "%d\t0x%2x\t%s\t0x%2x\t%s\t%s\n",
-			i, have[i], vm.OpCode(have[i]), want[i], vm.OpCode(want[i]), diff)
+			i, have[i], vm.Opcode(have[i]), want[i], vm.Opcode(want[i]), diff)
 	}
 	w.Flush()
 }
diff --git a/pkg/vm/compiler/tests/function_call_test.go b/pkg/vm/compiler/tests/function_call_test.go
index 4b41621be..947e86872 100644
--- a/pkg/vm/compiler/tests/function_call_test.go
+++ b/pkg/vm/compiler/tests/function_call_test.go
@@ -58,4 +58,19 @@ var functionCallTestCases = []testCase{
 		`,
 		"53c56b5a6c766b00527ac46c766b00c3616516006c766b51527ac46203006c766b51c3616c756653c56b6c766b00527ac4586c766b51527ac46203006c766b00c36c766b51c393616c7566",
 	},
+	{
+		"function call with multiple arguments",
+		`
+		package testcase
+		func Main() int {
+			x := addIntegers(2, 4)
+			return x
+		}
+
+		func addIntegers(x int, y int) int {
+			return x + y
+		}
+		`,
+		"52c56b52547c616516006c766b00527ac46203006c766b00c3616c756653c56b6c766b00527ac46c766b51527ac46203006c766b00c36c766b51c393616c7566",
+	},
 }
diff --git a/pkg/vm/compiler/tests/struct_test.go b/pkg/vm/compiler/tests/struct_test.go
new file mode 100644
index 000000000..758fcbe17
--- /dev/null
+++ b/pkg/vm/compiler/tests/struct_test.go
@@ -0,0 +1,157 @@
+package compiler_test
+
+var structTestCases = []testCase{
+	{
+		"struct field assign",
+		`
+		package foo
+		type token struct {
+			x int 
+			y int
+		}
+
+		func Main() int {
+			t := token {
+				x: 2,
+				y: 4,
+			}
+
+			age := t.x
+			return age
+		}
+		`,
+		"53c56b6152c66b526c766b00527ac4546c766b51527ac46c6c766b00527ac46c766b00c300c36c766b51527ac46203006c766b51c3616c7566",
+	},
+	{
+		"struct field return",
+		`
+		package foo
+		type token struct {
+			x int
+			y int
+		}
+
+		func Main() int {
+			t := token {
+				x: 2,
+				y: 4,
+			}
+
+			return t.x
+		}
+		`,
+		"52c56b6152c66b526c766b00527ac4546c766b51527ac46c6c766b00527ac46203006c766b00c300c3616c7566",
+	},
+	{
+		"struct field assign",
+		`
+		package foo
+		type token struct {
+			x int
+			y int
+		}
+
+		func Main() int {
+			t := token {
+				x: 2,
+				y: 4,
+			}
+			t.x = 10
+			return t.x
+		}
+		`,
+		"53c56b6152c66b526c766b00527ac4546c766b51527ac46c6c766b00527ac45a6c766b00c3007bc46203006c766b00c300c3616c7566",
+	},
+	{
+		"complex struct",
+		`
+		package foo
+		type token struct {
+			x int
+			y int
+		}
+
+		func Main() int {
+			x := 10
+
+			t := token {
+				x: 2,
+				y: 4,
+			}
+
+			y := x + t.x
+
+			return y
+		}
+		`,
+		"54c56b5a6c766b00527ac46152c66b526c766b00527ac4546c766b51527ac46c6c766b51527ac46c766b00c36c766b51c300c3936c766b52527ac46203006c766b52c3616c7566",
+	},
+	{
+		"initialize same struct twice",
+		`
+		package foo
+		type token struct {
+			x int
+			y int
+		}
+
+		func Main() int {
+			t1 := token {
+				x: 2,
+				y: 4,
+			}
+			t2 := token {
+				x: 2,
+				y: 4,
+			}
+			return t1.x + t2.y
+		}
+		`,
+		"53c56b6152c66b526c766b00527ac4546c766b51527ac46c6c766b00527ac46152c66b526c766b00527ac4546c766b51527ac46c6c766b51527ac46203006c766b00c300c36c766b51c351c393616c7566",
+	},
+	{
+		"struct methods",
+		`
+		package foo
+		type token struct {
+			x int
+		}
+
+		func(t token) getInteger() int {
+			return t.x
+		}
+
+		func Main() int {
+			t := token {
+				x: 4, 
+			}
+			someInt := t.getInteger()
+			return someInt
+		}
+		`,
+		"53c56b6151c66b546c766b00527ac46c6c766b00527ac46c766b00c3616516006c766b51527ac46203006c766b51c3616c756652c56b6c766b00527ac46203006c766b00c300c3616c7566",
+	},
+	{
+		"struct methods with arguments",
+		`
+		package foo
+		type token struct {
+			x int
+		}
+
+		// Also tests if x conflicts with t.x
+		func(t token) addIntegers(x int, y int) int {
+			return t.x + x + y
+		}
+
+		func Main() int {
+			t := token {
+				x: 4, 
+			}
+			someInt := t.addIntegers(2, 4)
+			return someInt
+		}
+		`,
+		"53c56b6151c66b546c766b00527ac46c6c766b00527ac46c766b00c352545272616516006c766b51527ac46203006c766b51c3616c756654c56b6c766b00527ac46c766b51527ac46c766b52527ac46203006c766b00c300c36c766b51c3936c766b52c393616c7566",
+	},
+}
diff --git a/pkg/vm/opcode.go b/pkg/vm/opcode.go
index cf36bc059..724df2616 100644
--- a/pkg/vm/opcode.go
+++ b/pkg/vm/opcode.go
@@ -1,129 +1,129 @@
 package vm
 
-// OpCode is an single operational instruction for the GO NEO virtual machine.
-type OpCode byte
+// Opcode is an single operational instruction for the GO NEO virtual machine.
+type Opcode byte
 
 // List of supported opcodes.
 const (
 	// Constants
-	OpPush0       OpCode = 0x00 // An empty array of bytes is pushed onto the stack.
-	OpPushF       OpCode = OpPush0
-	OpPushBytes1  OpCode = 0x01 // 0x01-0x4B The next opcode bytes is data to be pushed onto the stack
-	OpPushBytes75 OpCode = 0x4B
-	OpPushData1   OpCode = 0x4C // The next byte contains the number of bytes to be pushed onto the stack.
-	OpPushData2   OpCode = 0x4D // The next two bytes contain the number of bytes to be pushed onto the stack.
-	OpPushData4   OpCode = 0x4E // The next four bytes contain the number of bytes to be pushed onto the stack.
-	OpPushM1      OpCode = 0x4F // The number -1 is pushed onto the stack.
-	OpPush1       OpCode = 0x51
-	OpPushT       OpCode = OpPush1
-	OpPush2       OpCode = 0x52 // The number 2 is pushed onto the stack.
-	OpPush3       OpCode = 0x53 // The number 3 is pushed onto the stack.
-	OpPush4       OpCode = 0x54 // The number 4 is pushed onto the stack.
-	OpPush5       OpCode = 0x55 // The number 5 is pushed onto the stack.
-	OpPush6       OpCode = 0x56 // The number 6 is pushed onto the stack.
-	OpPush7       OpCode = 0x57 // The number 7 is pushed onto the stack.
-	OpPush8       OpCode = 0x58 // The number 8 is pushed onto the stack.
-	OpPush9       OpCode = 0x59 // The number 9 is pushed onto the stack.
-	OpPush10      OpCode = 0x5A // The number 10 is pushed onto the stack.
-	OpPush11      OpCode = 0x5B // The number 11 is pushed onto the stack.
-	OpPush12      OpCode = 0x5C // The number 12 is pushed onto the stack.
-	OpPush13      OpCode = 0x5D // The number 13 is pushed onto the stack.
-	OpPush14      OpCode = 0x5E // The number 14 is pushed onto the stack.
-	OpPush15      OpCode = 0x5F // The number 15 is pushed onto the stack.
-	OpPush16      OpCode = 0x60 // The number 16 is pushed onto the stack.
+	Opush0       Opcode = 0x00 // An empty array of bytes is pushed onto the stack.
+	Opushf       Opcode = Opush0
+	Opushbytes1  Opcode = 0x01 // 0x01-0x4B The next opcode bytes is data to be pushed onto the stack
+	Opushbytes75 Opcode = 0x4B
+	Opushdata1   Opcode = 0x4C // The next byte contains the number of bytes to be pushed onto the stack.
+	Opushdata2   Opcode = 0x4D // The next two bytes contain the number of bytes to be pushed onto the stack.
+	Opushdata4   Opcode = 0x4E // The next four bytes contain the number of bytes to be pushed onto the stack.
+	Opushm1      Opcode = 0x4F // The number -1 is pushed onto the stack.
+	Opush1       Opcode = 0x51
+	Opusht       Opcode = Opush1
+	Opush2       Opcode = 0x52 // The number 2 is pushed onto the stack.
+	Opush3       Opcode = 0x53 // The number 3 is pushed onto the stack.
+	Opush4       Opcode = 0x54 // The number 4 is pushed onto the stack.
+	Opush5       Opcode = 0x55 // The number 5 is pushed onto the stack.
+	Opush6       Opcode = 0x56 // The number 6 is pushed onto the stack.
+	Opush7       Opcode = 0x57 // The number 7 is pushed onto the stack.
+	Opush8       Opcode = 0x58 // The number 8 is pushed onto the stack.
+	Opush9       Opcode = 0x59 // The number 9 is pushed onto the stack.
+	Opush10      Opcode = 0x5A // The number 10 is pushed onto the stack.
+	Opush11      Opcode = 0x5B // The number 11 is pushed onto the stack.
+	Opush12      Opcode = 0x5C // The number 12 is pushed onto the stack.
+	Opush13      Opcode = 0x5D // The number 13 is pushed onto the stack.
+	Opush14      Opcode = 0x5E // The number 14 is pushed onto the stack.
+	Opush15      Opcode = 0x5F // The number 15 is pushed onto the stack.
+	Opush16      Opcode = 0x60 // The number 16 is pushed onto the stack.
 
 	// Flow control
-	OpNOP      OpCode = 0x61 // No operation.
-	OpJMP      OpCode = 0x62
-	OpJMPIF    OpCode = 0x63
-	OpJMPIFNOT OpCode = 0x64
-	OpCall     OpCode = 0x65
-	OpRET      OpCode = 0x66
-	OpAppCall  OpCode = 0x67
-	OpSysCall  OpCode = 0x68
-	OpTailCall OpCode = 0x69
+	Onop      Opcode = 0x61 // No operation.
+	Ojmp      Opcode = 0x62
+	Ojmpif    Opcode = 0x63
+	Ojmpifnot Opcode = 0x64
+	Ocall     Opcode = 0x65
+	Oret      Opcode = 0x66
+	Opcall    Opcode = 0x67
+	Osyscall  Opcode = 0x68
+	Otailcall Opcode = 0x69
 
 	// The stack
-	OpDupFromAltStack OpCode = 0x6A
-	OpToAltStack      OpCode = 0x6B // Puts the input onto the top of the alt stack. Removes it from the main stack.
-	OpFromAltStack    OpCode = 0x6C // Puts the input onto the top of the main stack. Removes it from the alt stack.
-	OpXDrop           OpCode = 0x6D
-	OpXSwap           OpCode = 0x72
-	OpXTuck           OpCode = 0x73
-	OpDepth           OpCode = 0x74 // Puts the number of stack items onto the stack.
-	OpDrop            OpCode = 0x75 // Removes the top stack item.
-	OpDup             OpCode = 0x76 // Duplicates the top stack item.
-	OpNip             OpCode = 0x77 // Removes the second-to-top stack item.
-	OpOver            OpCode = 0x78 // Copies the second-to-top stack item to the top.
-	OpPick            OpCode = 0x79 // The item n back in the stack is copied to the top.
-	OpRoll            OpCode = 0x7A // The item n back in the stack is moved to the top.
-	OpRot             OpCode = 0x7B // The top three items on the stack are rotated to the left.
-	OpSwap            OpCode = 0x7C // The top two items on the stack are swapped.
-	OpTuck            OpCode = 0x7D // The item at the top of the stack is copied and inserted before the second-to-top item.
+	Odupfromaltstack Opcode = 0x6A
+	Otoaltstack      Opcode = 0x6B // Puts the input onto the top of the alt stack. Removes it from the main stack.
+	Ofromaltstack    Opcode = 0x6C // Puts the input onto the top of the main stack. Removes it from the alt stack.
+	Oxdrop           Opcode = 0x6D
+	Oxswap           Opcode = 0x72
+	Oxtuck           Opcode = 0x73
+	Odepth           Opcode = 0x74 // Puts the number of stack items onto the stack.
+	Odrop            Opcode = 0x75 // Removes the top stack item.
+	Odup             Opcode = 0x76 // Duplicates the top stack item.
+	Onip             Opcode = 0x77 // Removes the second-to-top stack item.
+	Oover            Opcode = 0x78 // Copies the second-to-top stack item to the top.
+	Opick            Opcode = 0x79 // The item n back in the stack is copied to the top.
+	Oroll            Opcode = 0x7A // The item n back in the stack is moved to the top.
+	Orot             Opcode = 0x7B // The top three items on the stack are rotated to the left.
+	Oswap            Opcode = 0x7C // The top two items on the stack are swapped.
+	Otuck            Opcode = 0x7D // The item at the top of the stack is copied and inserted before the second-to-top item.
 
 	// Splice
-	OpCat    OpCode = 0x7E // Concatenates two strings.
-	OpSubStr OpCode = 0x7F // Returns a section of a string.
-	OpLeft   OpCode = 0x80 // Keeps only characters left of the specified point in a string.
-	OpRight  OpCode = 0x81 // Keeps only characters right of the specified point in a string.
-	OpSize   OpCode = 0x82 // Returns the length of the input string.
+	Ocat    Opcode = 0x7E // Concatenates two strings.
+	Osubstr Opcode = 0x7F // Returns a section of a string.
+	Oleft   Opcode = 0x80 // Keeps only characters left of the specified point in a string.
+	Oright  Opcode = 0x81 // Keeps only characters right of the specified point in a string.
+	Osize   Opcode = 0x82 // Returns the length of the input string.
 
 	// Bitwise logic
-	OpInvert OpCode = 0x83 // Flips all of the bits in the input.
-	OpAnd    OpCode = 0x84 // Boolean and between each bit in the inputs.
-	OpOr     OpCode = 0x85 // Boolean or between each bit in the inputs.
-	OpXor    OpCode = 0x86 // Boolean exclusive or between each bit in the inputs.
-	OpEqual  OpCode = 0x87 // Returns 1 if the inputs are exactly equal, 0 otherwise.
+	Oinvert Opcode = 0x83 // Flips all of the bits in the input.
+	Oand    Opcode = 0x84 // Boolean and between each bit in the inputs.
+	Oor     Opcode = 0x85 // Boolean or between each bit in the inputs.
+	Oxor    Opcode = 0x86 // Boolean exclusive or between each bit in the inputs.
+	Oequal  Opcode = 0x87 // Returns 1 if the inputs are exactly equal, 0 otherwise.
 
 	// Arithmetic
 	// Note: Arithmetic inputs are limited to signed 32-bit integers, but may overflow their output.
-	OpInc         OpCode = 0x8B // 1 is added to the input.
-	OpDec         OpCode = 0x8C // 1 is subtracted from the input.
-	OpSign        OpCode = 0x8D
-	OpNegate      OpCode = 0x8F // The sign of the input is flipped.
-	OpAbs         OpCode = 0x90 // The input is made positive.
-	OpNot         OpCode = 0x91 // If the input is 0 or 1, it is flipped. Otherwise the output will be 0.
-	OpNZ          OpCode = 0x92 // Returns 0 if the input is 0. 1 otherwise.
-	OpAdd         OpCode = 0x93 // a is added to b.
-	OpSub         OpCode = 0x94 // b is subtracted from a.
-	OpMul         OpCode = 0x95 // a is multiplied by b.
-	OpDiv         OpCode = 0x96 // a is divided by b.
-	OpMod         OpCode = 0x97 // Returns the remainder after dividing a by b.
-	OpShl         OpCode = 0x98 // Shifts a left b bits, preserving sign.
-	OpShr         OpCode = 0x99 // Shifts a right b bits, preserving sign.
-	OpBoolAnd     OpCode = 0x9A // If both a and b are not 0, the output is 1. Otherwise 0.
-	OpBoolOr      OpCode = 0x9B // If a or b is not 0, the output is 1. Otherwise 0.
-	OpNumEqual    OpCode = 0x9C // Returns 1 if the numbers are equal, 0 otherwise.
-	OpNumNotEqual OpCode = 0x9E // Returns 1 if the numbers are not equal, 0 otherwise.
-	OpLT          OpCode = 0x9F // Returns 1 if a is less than b, 0 otherwise.
-	OpGT          OpCode = 0xA0 // Returns 1 if a is greater than b, 0 otherwise.
-	OpLTE         OpCode = 0xA1 // Returns 1 if a is less than or equal to b, 0 otherwise.
-	OpGTE         OpCode = 0xA2 // Returns 1 if a is greater than or equal to b, 0 otherwise.
-	OpMin         OpCode = 0xA3 // Returns the smaller of a and b.
-	OpMax         OpCode = 0xA4 // Returns the larger of a and b.
-	OpWithin      OpCode = 0xA5 // Returns 1 if x is within the specified range (left-inclusive), 0 otherwise.
+	Oinc         Opcode = 0x8B // 1 is added to the input.
+	Odec         Opcode = 0x8C // 1 is subtracted from the input.
+	Osign        Opcode = 0x8D
+	Onegate      Opcode = 0x8F // The sign of the input is flipped.
+	Oabs         Opcode = 0x90 // The input is made positive.
+	Onot         Opcode = 0x91 // If the input is 0 or 1, it is flipped. Otherwise the output will be 0.
+	Onz          Opcode = 0x92 // Returns 0 if the input is 0. 1 otherwise.
+	Oadd         Opcode = 0x93 // a is added to b.
+	Osub         Opcode = 0x94 // b is subtracted from a.
+	Omul         Opcode = 0x95 // a is multiplied by b.
+	Odiv         Opcode = 0x96 // a is divided by b.
+	Omod         Opcode = 0x97 // Returns the remainder after dividing a by b.
+	Oshl         Opcode = 0x98 // Shifts a left b bits, preserving sign.
+	Oshr         Opcode = 0x99 // Shifts a right b bits, preserving sign.
+	Obooland     Opcode = 0x9A // If both a and b are not 0, the output is 1. Otherwise 0.
+	Oboolor      Opcode = 0x9B // If a or b is not 0, the output is 1. Otherwise 0.
+	Onumequal    Opcode = 0x9C // Returns 1 if the numbers are equal, 0 otherwise.
+	Onumnotequal Opcode = 0x9E // Returns 1 if the numbers are not equal, 0 otherwise.
+	Olt          Opcode = 0x9F // Returns 1 if a is less than b, 0 otherwise.
+	Ogt          Opcode = 0xA0 // Returns 1 if a is greater than b, 0 otherwise.
+	Olte         Opcode = 0xA1 // Returns 1 if a is less than or equal to b, 0 otherwise.
+	Ogte         Opcode = 0xA2 // Returns 1 if a is greater than or equal to b, 0 otherwise.
+	Omin         Opcode = 0xA3 // Returns the smaller of a and b.
+	Omax         Opcode = 0xA4 // Returns the larger of a and b.
+	Owithin      Opcode = 0xA5 // Returns 1 if x is within the specified range (left-inclusive), 0 otherwise.
 
 	// Crypto
-	OpSHA1          OpCode = 0xA7 // The input is hashed using SHA-1.
-	OpSHA256        OpCode = 0xA8 // The input is hashed using SHA-256.
-	OpHASH160       OpCode = 0xA9
-	OpHASH256       OpCode = 0xAA
-	OpCheckSig      OpCode = 0xAC
-	OpCheckMultiSig OpCode = 0xAE
+	Osha1          Opcode = 0xA7 // The input is hashed using SHA-1.
+	Osha256        Opcode = 0xA8 // The input is hashed using SHA-256.
+	Ohash160       Opcode = 0xA9
+	Ohash256       Opcode = 0xAA
+	Ochecksig      Opcode = 0xAC
+	Ocheckmultisig Opcode = 0xAE
 
-	// Array
-	OpArraySize OpCode = 0xC0
-	OpPack      OpCode = 0xC1
-	OpUnpack    OpCode = 0xC2
-	OpPickItem  OpCode = 0xC3
-	OpSetItem   OpCode = 0xC4
-	OpNewArray  OpCode = 0xC5 // Pops size from stack and creates a new array with that size, and pushes the array into the stack
-	OpNewStruct OpCode = 0xC6
-	OpAppend    OpCode = 0xC8
-	OpReverse   OpCode = 0xC9
-	OpRemove    OpCode = 0xCA
+	// array
+	Oarraysize Opcode = 0xC0
+	Opack      Opcode = 0xC1
+	Ounpack    Opcode = 0xC2
+	Opickitem  Opcode = 0xC3
+	Osetitem   Opcode = 0xC4
+	Onewarray  Opcode = 0xC5 // Pops size from stack and creates a new array with that size, and pushes the array into the stack
+	Onewstruct Opcode = 0xC6
+	Oappend    Opcode = 0xC8
+	Oreverse   Opcode = 0xC9
+	Oremove    Opcode = 0xCA
 
-	// Exceptions
-	OpThrow      OpCode = 0xF0
-	OpThrowIfNot OpCode = 0xF1
+	// exceptions
+	Othrow      Opcode = 0xF0
+	Othrowifnot Opcode = 0xF1
 )
diff --git a/pkg/vm/opcode_string.go b/pkg/vm/opcode_string.go
index 67e922e35..5d118ec0b 100644
--- a/pkg/vm/opcode_string.go
+++ b/pkg/vm/opcode_string.go
@@ -1,118 +1,118 @@
-// Code generated by "stringer -type=OpCode ./pkg/vm"; DO NOT EDIT.
+// Code generated by "stringer -type=Opcode ./pkg/vm/compiler"; DO NOT EDIT.
 
 package vm
 
 import "strconv"
 
-const _OpCode_name = "OpPush0OpPushBytes1OpPushBytes75OpPushData1OpPushData2OpPushData4OpPushM1OpPush1OpPush2OpPush3OpPush4OpPush5OpPush6OpPush7OpPush8OpPush9OpPush10OpPush11OpPush12OpPush13OpPush14OpPush15OpPush16OpNOPOpJMPOpJMPIFOpJMPIFNOTOpCallOpRETOpAppCallOpSysCallOpTailCallOpDupFromAltStackOpToAltStackOpFromAltStackOpXDropOpXSwapOpXTuckOpDepthOpDropOpDupOpNipOpOverOpPickOpRollOpRotOpSwapOpTuckOpCatOpSubStrOpLeftOpRightOpSizeOpInvertOpAndOpOrOpXorOpEqualOpIncOpDecOpSignOpNegateOpAbsOpNotOpNZOpAddOpSubOpMulOpDivOpModOpShlOpShrOpBoolAndOpBoolOrOpNumEqualOpNumNotEqualOpLTOpGTOpLTEOpGTEOpMinOpMaxOpWithinOpSHA1OpSHA256OpHASH160OpHASH256OpCheckSigOpCheckMultiSigOpArraySizeOpPackOpUnpackOpPickItemOpSetItemOpNewArrayOpNewStructOpAppendOpReverseOpRemoveOpThrowOpThrowIfNot"
+const _Opcode_name = "Opush0Opushbytes1Opushbytes75Opushdata1Opushdata2Opushdata4Opushm1Opush1Opush2Opush3Opush4Opush5Opush6Opush7Opush8Opush9Opush10Opush11Opush12Opush13Opush14Opush15Opush16OnopOjmpOjmpifOjmpifnotOcallOretOpcallOsyscallOtailcallOdupfromaltstackOtoaltstackOfromaltstackOxdropOxswapOxtuckOdepthOdropOdupOnipOoverOpickOrollOrotOswapOtuckOcatOsubstrOleftOrightOsizeOinvertOandOorOxorOequalOincOdecOsignOnegateOabsOnotOnzOaddOsubOmulOdivOmodOshlOshrOboolandOboolorOnumequalOnumnotequalOltOgtOlteOgteOminOmaxOwithinOsha1Osha256Ohash160Ohash256OchecksigOcheckmultisigOarraysizeOpackOunpackOpickitemOsetitemOnewarrayOnewstructOappendOreverseOremoveOthrowOthrowifnot"
 
-var _OpCode_map = map[OpCode]string{
-	0:   _OpCode_name[0:7],
-	1:   _OpCode_name[7:19],
-	75:  _OpCode_name[19:32],
-	76:  _OpCode_name[32:43],
-	77:  _OpCode_name[43:54],
-	78:  _OpCode_name[54:65],
-	79:  _OpCode_name[65:73],
-	81:  _OpCode_name[73:80],
-	82:  _OpCode_name[80:87],
-	83:  _OpCode_name[87:94],
-	84:  _OpCode_name[94:101],
-	85:  _OpCode_name[101:108],
-	86:  _OpCode_name[108:115],
-	87:  _OpCode_name[115:122],
-	88:  _OpCode_name[122:129],
-	89:  _OpCode_name[129:136],
-	90:  _OpCode_name[136:144],
-	91:  _OpCode_name[144:152],
-	92:  _OpCode_name[152:160],
-	93:  _OpCode_name[160:168],
-	94:  _OpCode_name[168:176],
-	95:  _OpCode_name[176:184],
-	96:  _OpCode_name[184:192],
-	97:  _OpCode_name[192:197],
-	98:  _OpCode_name[197:202],
-	99:  _OpCode_name[202:209],
-	100: _OpCode_name[209:219],
-	101: _OpCode_name[219:225],
-	102: _OpCode_name[225:230],
-	103: _OpCode_name[230:239],
-	104: _OpCode_name[239:248],
-	105: _OpCode_name[248:258],
-	106: _OpCode_name[258:275],
-	107: _OpCode_name[275:287],
-	108: _OpCode_name[287:301],
-	109: _OpCode_name[301:308],
-	114: _OpCode_name[308:315],
-	115: _OpCode_name[315:322],
-	116: _OpCode_name[322:329],
-	117: _OpCode_name[329:335],
-	118: _OpCode_name[335:340],
-	119: _OpCode_name[340:345],
-	120: _OpCode_name[345:351],
-	121: _OpCode_name[351:357],
-	122: _OpCode_name[357:363],
-	123: _OpCode_name[363:368],
-	124: _OpCode_name[368:374],
-	125: _OpCode_name[374:380],
-	126: _OpCode_name[380:385],
-	127: _OpCode_name[385:393],
-	128: _OpCode_name[393:399],
-	129: _OpCode_name[399:406],
-	130: _OpCode_name[406:412],
-	131: _OpCode_name[412:420],
-	132: _OpCode_name[420:425],
-	133: _OpCode_name[425:429],
-	134: _OpCode_name[429:434],
-	135: _OpCode_name[434:441],
-	139: _OpCode_name[441:446],
-	140: _OpCode_name[446:451],
-	141: _OpCode_name[451:457],
-	143: _OpCode_name[457:465],
-	144: _OpCode_name[465:470],
-	145: _OpCode_name[470:475],
-	146: _OpCode_name[475:479],
-	147: _OpCode_name[479:484],
-	148: _OpCode_name[484:489],
-	149: _OpCode_name[489:494],
-	150: _OpCode_name[494:499],
-	151: _OpCode_name[499:504],
-	152: _OpCode_name[504:509],
-	153: _OpCode_name[509:514],
-	154: _OpCode_name[514:523],
-	155: _OpCode_name[523:531],
-	156: _OpCode_name[531:541],
-	158: _OpCode_name[541:554],
-	159: _OpCode_name[554:558],
-	160: _OpCode_name[558:562],
-	161: _OpCode_name[562:567],
-	162: _OpCode_name[567:572],
-	163: _OpCode_name[572:577],
-	164: _OpCode_name[577:582],
-	165: _OpCode_name[582:590],
-	167: _OpCode_name[590:596],
-	168: _OpCode_name[596:604],
-	169: _OpCode_name[604:613],
-	170: _OpCode_name[613:622],
-	172: _OpCode_name[622:632],
-	174: _OpCode_name[632:647],
-	192: _OpCode_name[647:658],
-	193: _OpCode_name[658:664],
-	194: _OpCode_name[664:672],
-	195: _OpCode_name[672:682],
-	196: _OpCode_name[682:691],
-	197: _OpCode_name[691:701],
-	198: _OpCode_name[701:712],
-	200: _OpCode_name[712:720],
-	201: _OpCode_name[720:729],
-	202: _OpCode_name[729:737],
-	240: _OpCode_name[737:744],
-	241: _OpCode_name[744:756],
+var _Opcode_map = map[Opcode]string{
+	0:   _Opcode_name[0:6],
+	1:   _Opcode_name[6:17],
+	75:  _Opcode_name[17:29],
+	76:  _Opcode_name[29:39],
+	77:  _Opcode_name[39:49],
+	78:  _Opcode_name[49:59],
+	79:  _Opcode_name[59:66],
+	81:  _Opcode_name[66:72],
+	82:  _Opcode_name[72:78],
+	83:  _Opcode_name[78:84],
+	84:  _Opcode_name[84:90],
+	85:  _Opcode_name[90:96],
+	86:  _Opcode_name[96:102],
+	87:  _Opcode_name[102:108],
+	88:  _Opcode_name[108:114],
+	89:  _Opcode_name[114:120],
+	90:  _Opcode_name[120:127],
+	91:  _Opcode_name[127:134],
+	92:  _Opcode_name[134:141],
+	93:  _Opcode_name[141:148],
+	94:  _Opcode_name[148:155],
+	95:  _Opcode_name[155:162],
+	96:  _Opcode_name[162:169],
+	97:  _Opcode_name[169:173],
+	98:  _Opcode_name[173:177],
+	99:  _Opcode_name[177:183],
+	100: _Opcode_name[183:192],
+	101: _Opcode_name[192:197],
+	102: _Opcode_name[197:201],
+	103: _Opcode_name[201:207],
+	104: _Opcode_name[207:215],
+	105: _Opcode_name[215:224],
+	106: _Opcode_name[224:240],
+	107: _Opcode_name[240:251],
+	108: _Opcode_name[251:264],
+	109: _Opcode_name[264:270],
+	114: _Opcode_name[270:276],
+	115: _Opcode_name[276:282],
+	116: _Opcode_name[282:288],
+	117: _Opcode_name[288:293],
+	118: _Opcode_name[293:297],
+	119: _Opcode_name[297:301],
+	120: _Opcode_name[301:306],
+	121: _Opcode_name[306:311],
+	122: _Opcode_name[311:316],
+	123: _Opcode_name[316:320],
+	124: _Opcode_name[320:325],
+	125: _Opcode_name[325:330],
+	126: _Opcode_name[330:334],
+	127: _Opcode_name[334:341],
+	128: _Opcode_name[341:346],
+	129: _Opcode_name[346:352],
+	130: _Opcode_name[352:357],
+	131: _Opcode_name[357:364],
+	132: _Opcode_name[364:368],
+	133: _Opcode_name[368:371],
+	134: _Opcode_name[371:375],
+	135: _Opcode_name[375:381],
+	139: _Opcode_name[381:385],
+	140: _Opcode_name[385:389],
+	141: _Opcode_name[389:394],
+	143: _Opcode_name[394:401],
+	144: _Opcode_name[401:405],
+	145: _Opcode_name[405:409],
+	146: _Opcode_name[409:412],
+	147: _Opcode_name[412:416],
+	148: _Opcode_name[416:420],
+	149: _Opcode_name[420:424],
+	150: _Opcode_name[424:428],
+	151: _Opcode_name[428:432],
+	152: _Opcode_name[432:436],
+	153: _Opcode_name[436:440],
+	154: _Opcode_name[440:448],
+	155: _Opcode_name[448:455],
+	156: _Opcode_name[455:464],
+	158: _Opcode_name[464:476],
+	159: _Opcode_name[476:479],
+	160: _Opcode_name[479:482],
+	161: _Opcode_name[482:486],
+	162: _Opcode_name[486:490],
+	163: _Opcode_name[490:494],
+	164: _Opcode_name[494:498],
+	165: _Opcode_name[498:505],
+	167: _Opcode_name[505:510],
+	168: _Opcode_name[510:517],
+	169: _Opcode_name[517:525],
+	170: _Opcode_name[525:533],
+	172: _Opcode_name[533:542],
+	174: _Opcode_name[542:556],
+	192: _Opcode_name[556:566],
+	193: _Opcode_name[566:571],
+	194: _Opcode_name[571:578],
+	195: _Opcode_name[578:587],
+	196: _Opcode_name[587:595],
+	197: _Opcode_name[595:604],
+	198: _Opcode_name[604:614],
+	200: _Opcode_name[614:621],
+	201: _Opcode_name[621:629],
+	202: _Opcode_name[629:636],
+	240: _Opcode_name[636:642],
+	241: _Opcode_name[642:653],
 }
 
-func (i OpCode) String() string {
-	if str, ok := _OpCode_map[i]; ok {
+func (i Opcode) String() string {
+	if str, ok := _Opcode_map[i]; ok {
 		return str
 	}
-	return "OpCode(" + strconv.FormatInt(int64(i), 10) + ")"
+	return "Opcode(" + strconv.FormatInt(int64(i), 10) + ")"
 }