Improve comment

manager/eris-mint/evm/snative.go

@@ -187,6 +187,12 @@ func SNativeContracts() map[string]*SNativeContractDescription {
 
 	contractMap := make(map[string]*SNativeContractDescription, len(contracts))
 	for _, contract := range contracts {
+		if _, ok := contractMap[contract.Name]; ok {
+			// If this happens we have a pseudo compile time error that will be caught
+			// on native.go init()
+			panic(fmt.Errorf("Duplicate contract with name %s defined. " +
+					"Contract names must be unique.", contract.Name))
+		}
 		contractMap[contract.Name] = contract
 	}
 	return contractMap

util/snatives/templates/solidity_templates.go

@@ -25,9 +25,10 @@ import (
 
 const contractTemplateText = `/**
 [[.Comment]]
-* @dev These functions can be accessed as if this contract were deployed at the address [[.Address]].
-* @dev For readability you may wish to define the following constant to refer to the SNative contract:
-* @dev address constant [[.Name]]ContractAddress = [[.Address]]
+* @dev These functions can be accessed as if this contract were deployed at a special address ([[.Address]]).
+* @dev This special address is defined as the last 20 bytes of the sha3 hash of the the contract name.
+* @dev To instantiate the contract use:
+* @dev [[.Name]] [[.InstanceName]] = [[.Name]](address(sha3("[[.Name]]")));
 */
 contract [[.Name]] {[[range .Functions]]
 [[.SolidityIndent 1]]
@@ -69,11 +70,30 @@ type solidityFunction struct {
 	*vm.SNativeFunctionDescription
 }
 
+//
+// Contract
+//
+
 // Create a templated solidityContract from an SNative contract description
 func NewSolidityContract(contract *vm.SNativeContractDescription) *solidityContract {
 	return &solidityContract{contract}
 }
 
+func (contract *solidityContract) Comment() string {
+	return comment(contract.SNativeContractDescription.Comment)
+}
+
+// Get a version of the contract name to be used for an instance of the contract
+func (contract *solidityContract) InstanceName() string {
+	// Hopefully the contract name is UpperCamelCase. If it's not, oh well, this
+	// is meant to be illustrative rather than cast iron compilable
+	instanceName := strings.ToLower(contract.Name[:1]) + contract.Name[1:]
+	if instanceName == contract.Name {
+		return "contractInstance"
+	}
+	return instanceName
+}
+
 func (contract *solidityContract) Address() string {
 	return fmt.Sprintf("0x%x",
 		contract.SNativeContractDescription.Address())
@@ -98,6 +118,10 @@ func (contract *solidityContract) Functions() []*solidityFunction {
 	return solidityFunctions
 }
 
+//
+// Function
+//
+
 // Create a templated solidityFunction from an SNative function description
 func NewSolidityFunction(function *vm.SNativeFunctionDescription) *solidityFunction {
 	return &solidityFunction{function}
@@ -133,9 +157,11 @@ func (function *solidityFunction) solidity(indentLevel uint) (string, error) {
 	return buf.String(), nil
 }
 
-func (contract *solidityContract) Comment() string {
-	return comment(contract.SNativeContractDescription.Comment)
-}
+
+//
+// Contract
+//
+
 
 func comment(comment string) string {
 	commentLines := make([]string, 0, 5)