Smart Contract Reference

This reference documentation covers the five smart contracts used in the examples and was created from the Natspec comments in the Solidity source files.

HelloWorld1

Description: HelloWorld1
Purpose: The simplest contract to say hello to the world.
Notes: Uses a public state variable to hold the greeting
Author: Stephen Newell

STATE VARIABLES

greeting: Hello World greeting.

METHODS

None

EVENTS

None

HelloWorld2

Description: HelloWorld2
Purpose: A slightly more involved contract to say hello to the world.
Notes: Uses a function to return the greeting.
Author: Stephen Newell

STATE VARIABLES

None

METHODS

getGreeting()

Purpose: Return the Hello World greeting.
Notes: Function returns a string with the greeting defined in the function.

EVENTS

None

HelloWorld3

Description: HelloWorld3
Purpose: A more complex contract to say hello to the world.
Notes: Uses a transaction to set the greeting and a function to return the greeting.
Author: Stephen Newell

STATE VARIABLES

greeting: holds the Hello World greeting.

METHODS

getGreeting()

Purpose: Return the greeting.
Notes: Function returns a string with the current contract greeting.

Returns:

_0: greeting contract greeting value

setGreeting(string)

Purpose: Changes the greeting.
Notes: Update the contract greeting to this new message.

Parameters:

_greeting: new greeting message

EVENTS

None

HelloWorld4

Description: HelloWorld4
Purpose: Adds an event to the constructor.
Notes: Find the greeting in the emitted event.
Author: Stephen Newell

STATE VARIABLES

greeting: the greeting to display

METHODS

constructor()

Purpose: Create a new HelloWorld4 contract on the blockchain.
Notes: Emits HelloWord4().

Parameters:

_initGreeting: set as the greeting string

EVENTS

HelloWorld4Constructed(uint256,address,string,address)

Purpose: Emitted when contract is constructed

Parameters:

HelloWorld4: address of the newly deployed contract
initGreeting: constructor arg with a greeting
sender: address sending the constructor
timestamp: block time when constructed

Test

Description: Test Contract
Purpose: This is used to for testing simpleth methods. It is designed with very simple transactions, functions, and variables to support a wide variety of test cases.
Notes: All changes must be made with the Python unit tests in mind. Be cautious that you do not break anything. See the tests directory for PyTest tests that use this contract.
Author: Stephen Newell

STATE VARIABLES

initNum: set by constructor. Has no other purpose.
nums: used by the storeNums…() transactions
numsTotal: used by sumNums() to hold the sum of nums[].
owner: address that constructed and deployed the contract.
testAddr: used to store an address
testArray: used to store an array
testBool: used to store a boolean
testBytes: used to store a byte array
testBytes32: used to store a 32-byte value
testBytes4: used to store a four-byte value
testInt: used to store a signed integer
testStr: used to store a string
testUint: used to store an unsigned integer

METHODS

constructor()

Purpose: Create a new Test contract on the blockchain.
Notes: msg.sender becomes contract owner. Emits TestConstructed().

Parameters:

_initNum: value is stored in initNum variable

assertGreaterThan10(int256)

Purpose: Allows test of assert()
Notes: If _value <= 10, assert will fail and pass back a message.

Parameters:

_value: only used in assert() test. Greater than 10 passes assert(). 10, or less, fails assert().

destroy(address)

Purpose: Destroy the deployed test contract. Make it unusable.
Notes: This is irreversible. Once destroyed, a contract is still on the blockchain and transactions can be sent to it, but they will not have any effect. Any ether in the contract’s balance is sent to _to. After a contract is destroyed, its either is inaccessible. Emits Destroyed event. Must be owner to use.

Parameters:

_to: address to receive contract’s ether balance

divideInitNum(int256)

Purpose: Divides initNum by a divisor
Notes: Emits InitNumDivided(). Used to test for divide-by-zero errors by using 0 for divisor and for non-integer results by using 3, or other, for divisor

Parameters:

_divisor: divide initNum by this value

divideNums(uint256)

Purpose: Divides values in nums[]. There is no test for _divisor being zero. This is used to test a transaction that fails.
Notes: Emits NumsDivided()

getBytes()

Purpose: Function to return the three test byte values

Returns:

testBytes32_: 32-byte value in testBytes32
testBytes4_: four-byte value in testBytes4
testBytes_: byte string in testBytes

getNum(uint8)

Purpose: Function to return nums[index]

Parameters:

index: specifies the nums[] entry to return

Returns:

num: value for nums[index]

getNum0()

Purpose: Function to return nums[0]

Returns:

num: the first element of nums[]

getNums()

Purpose: Function to return an array
Notes: Shows how to return all values as a list

Returns:

_0: nums all values in nums[]

getTypes()

Purpose: Function to return multiple values
Notes: Shows how to return multiple values and types set with storeTypes()

Returns:

testAddr_: testAddress value
testArray_: testArray value
testBool_: testBool value
testEnum_: testEnum value
testInt_: testInt value
testStr_: testStr value
testUint_: testUint value

requireFailsFunction()

Purpose: Function with require() that fails
Notes: Require always passes badk a message.

setOwner(address)

Purpose: Allows current owner to assign a new owner
Notes: Emits OwnerSet().

Parameters:

_newOwner: address of the account to be the new owner

storeBytes(bytes4,bytes32,bytes)

Purpose: Stores various byte values
Notes: Emits BytesStored()

Parameters:

_testBytes: value to store in testBytes
_testBytes32: value to store in testBytes32
_testBytes4: value to store in testBytes4

storeNum(uint256,uint256)

Purpose: Stores one of the nums[]
Notes: Emits NumStored(). Used to test for out of bounds errors by giving bad value to _index.

Parameters:

_index: selects which nums[]
_num: value to store in nums[index]

storeNums(uint256,uint256,uint256)

Purpose: Stores the three args in nums[]
Notes: Emits NumsStored()

Parameters:

_num0: value to store in nums[0]
_num1: value to store in nums[1]
_num2: value to store in nums[2]

storeNumsAndDivide(uint256,uint256,uint256,uint256)

Purpose: Stores the three args in nums[] and call sumNums() to divide nums
Notes: There is no test to check for a _divisor of 0. Zero is used in testing for this transaction to call another transaction that fails.

Parameters:

_divisor: pass to divideNums() to divide the three nums
_num0: value to store in nums[0]
_num1: value to store in nums[1]
_num2: value to store in nums[2]

storeNumsAndPay(uint256,uint256,uint256)

Purpose: Stores the three args in nums[] and accepts a payment.
Notes: Emits NumsStored()

Parameters:

_num0: value to store in nums[0]
_num1: value to store in nums[1]
_num2: value to store in nums[2]

storeNumsAndSum(uint256,uint256,uint256)

Purpose: Stores the three args in nums[] and call sumNums() to sum the nums
Notes: Emits NumsStored() and NumsStoredAndSummed()

Parameters:

_num0: value to store in nums[0]
_num1: value to store in nums[1]
_num2: value to store in nums[2]

storeNumsWithNoEvent(uint256,uint256,uint256)

Purpose: Stores the three args in nums[] but does not emit an event.
Notes: Same as NumsStored() but this transaction does not emit NumsStored()

Parameters:

_num0: value to store in nums[0]
_num1: value to store in nums[1]
_num2: value to store in nums[2]

storeNumsWithThreeEvents(uint256,uint256,uint256)

Purpose: Stores the three args in nums[] and emits three different events.
Notes: Same as NumsStored() but this transaction emits Num0Stored(), Num1Stored(), Num2Stored() instead of NumsStored().

Parameters:

_num0: value to store in nums[0]
_num1: value to store in nums[1]
_num2: value to store in nums[2]

storeTypes(bool,uint8,uint256,int256,address,string,uint256[3])

Purpose: Stores a variety of data types into public state variables
Notes: Emits TypesStored()

Parameters:

_addr: address to store into testAddr
_array: array of three unsigned integers to store in testArray
_bool: boolean to store in testBool
_enum: enumerated Size to store in testEnum
_int: signed integer to store into testUnt
_str: string to store into testStr
_uint: unsigned integer to store in testUint

sumNums()

Purpose: Sums values in nums[] and stores in numsTotal
Notes: Emits NumsSummed()

sumTwoNums()

Purpose: Sums values in nums[0] and nums[1] and stores in numsTotal. Required to be owner to call
Notes: Emits TwoNumsSummed()

throwAssert()

Purpose: Allows test of assert().
Notes: Always asserts. No event emitted.

throwRevert()

Purpose: Allows test of revert() with no parameter for a message
Notes: Always reverts. No event emitted.

throwRevertWithMessage(string)

Purpose: Allows test of revert() with a description message
Notes: Always reverts. No event emitted.

Parameters:

_message_str: Passed back as the revert description.

EVENTS

BytesStored(uint256,bytes4,bytes32,bytes)

Purpose: Emitted when new byte values are stored

Parameters:

testBytes: a byte array value
testBytes32: a 32-byte value
testBytes4: a 4-byte value
timestamp: block time when nums were updated

Destroyed(uint256,uint256)

Purpose: Emitted when contract is destroyed

Parameters:

amountGwei: contract’s ether balance sent to owner
timestamp: block time when paid

InitNumDivided(uint256,int256,int256)

Purpose: Emitted when new num1 is stored

Parameters:

divisor: used to divide initNum
result: resulting initNum
timestamp: block time when initNum was updated

Num0Stored(uint256,uint256)

Purpose: Emitted when num0 is stored

Parameters:

num0: stored in nums[0]
timestamp: block time when nums were updated

Num1Stored(uint256,uint256)

Purpose: Emitted when new num1 is stored

Parameters:

num1: stored in nums[1]
timestamp: block time when nums were updated

Num2Stored(uint256,uint256)

Purpose: Emitted when new num2 is stored

Parameters:

num2: stored in nums[2]
timestamp: block time when nums were updated

NumStored(uint256,uint256,uint256)

Purpose: Emitted when a selected nums[] is stored

Parameters:

index: into nums[]
num: stored in nums[index]
timestamp: block time when nums was updated

NumsDivided(uint256,uint256,uint256,uint256,uint256)

Purpose: Emitted when nums[] are divided

Parameters:

divisor: value used to divide nums[]
num0: value in nums[0] after dividing
num1: value in nums[1] after dividing
num2: value in nums[2] after dividing
timestamp: block time when nums divided

NumsStored(uint256,uint256,uint256,uint256)

Purpose: Emitted when new nums are stored

Parameters:

num0: stored in nums[0]. It is indexed for some test cases.
num1: stored in nums[1]
num2: stored in nums[2]
timestamp: block time when nums were updated

NumsStoredAndDivided(uint256)

Purpose: Emitted when nums were stored and then divided

Parameters:

timestamp: block time after nums[] divided

NumsStoredAndPaid(uint256,uint256,uint256,uint256,uint256,uint256)

Purpose: Emitted when new nums are stored along with a value (in wei) sent as a payment.

Parameters:

balance: amount of wei in contract’s balance
num0: stored in nums[0]
num1: stored in nums[1]
num2: stored in nums[2]
paid: amount of wei sent
timestamp: block time when nums were updated

NumsStoredAndSummed(uint256)

Purpose: Emitted when nums were stored and then summed

Parameters:

timestamp: block time after total was stored

NumsSummed(uint256,uint256,uint256,uint256,uint256)

Purpose: Emitted when nums[] total is stored

Parameters:

num0: value in nums[0]
num1: value in nums[1]
num2: value in nums[2]
timestamp: block time when total is stored
total: sum of the three nums assigned to numsTotal

OwnerSet(uint256,address)

Purpose: Emitted when owner is changed

Parameters:

newOwner: address of the new owner
timestamp: block time when owner was set

Received(uint256,address,uint256)

Purpose: Emitted when contract address is sent ether

Parameters:

amountWei: of ether received (in wei)
sender: address sending the ether
timestamp: block time when paid

TestConstructed(uint256,address,int256,address)

Purpose: Emitted when the contract is deployed.
Notes: Parameters are arbitrary.

Parameters:

Test: address of this contract
initNum: value assigned with constructor()
sender: becomes the address of owner
timestamp: block time, in epoch seconds, when deployed

TwoNumsSummed(uint256,uint256,uint256,uint256)

Purpose: Emitted when nums[0] and nums[1] total is stored

Parameters:

num0: value in nums[0]
num1: value in nums[1]
timestamp: block time when total is stored
total: sum of the first two nums assigned to numsTotal

TypesStored(uint256,bool,uint8,uint256,int256,address,string,uint256[3])

Purpose: Emitted when the four different types of variables are stored

Parameters:

testAddr: value given to the address variable
testArray: values given to the array
testBool: value given to the boolean variable
testEnum: value given to the enumerated variable
testInt: value given to the signed integer variable
testStr: value given to the string variable
testUint: value given to the unsigned integer variable
timestamp: block time when variables were updated