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Update introduction-to-smart-contracts.rst

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modifying "write" to "transactions"
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andreb0x 2022-03-07 10:57:56 -05:00 committed by nishant-sachdeva
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docs/introduction-to-smart-contracts.rst
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@ -396,13 +396,13 @@ returns that code when executed.
Gas Gas
=== ===
Upon creation, each transaction is charged with a certain amount of **gas**. Upon creation, each transaction is charged with a certain amount of **gas**.
Imposing a cost on operations that write to the blockchain serves to secure the network: Imposing a cost on transactions serves to secure the network:
it deincentivizes bad actors from spamming, and pays validators (i.e. miners and stakers) it deincentivizes bad actors from spamming, and pays validators (i.e. miners and stakers)
for the work that is required to validate new blocks. While the EVM executes the for the work that is required to validate new blocks. While the EVM executes the
transaction, the gas is gradually depleted according to specific rules. transaction, the gas is gradually depleted according to specific rules.
The **gas price** is a value set by the creator of the transaction (see `msg.sender), who The **gas price** is a value set by the originator of the transaction, i.e. `tx.origin`, who
has to pay ``gas_price * gas`` up front from the sending account. has to pay ``gas_price * gas`` up front from the sending account.
If some gas is left after execution, it is refunded to the transaction originator. If some gas is left after execution, it is refunded to the transaction originator.
@ -505,25 +505,14 @@ Delegatecall / Callcode and Libraries
There exists a special variant of a message call, named **delegatecall** There exists a special variant of a message call, named **delegatecall**
which is identical to a message call apart from the fact that which is identical to a message call apart from the fact that
the code at the target address is executed in the context of the calling the code at the target address is executed in the context of the calling
<<<<<<< HEAD
contract. In practice this means ``msg.sender`` and ``msg.value`` retain contract. In practice this means ``msg.sender`` and ``msg.value`` retain
the values that were passed to the delegator, while executing code that the values that were passed to the delegator, while executing code that
lives in the delegated contract. lives in the delegated contract.
=======
contract. In practice this means ``msg.sender`` and ``msg.value`` retain
the values that were passed to the delegator, while executing code that
lives in the delegated contract.
>>>>>>> updates to delegatecall
This means that a contract can dynamically load code from a different This means that a contract can dynamically load code from a different
address at runtime. Storage, current address and balance still address at runtime. Storage, current address and balance still
refer to the calling contract, only the code is taken from the called address. refer to the calling contract, only the code is taken from the called address.
For example, say Alice calls a method in contract A to modify
state variable `A.var` according to method ``A.foo()``.
If contract A then delegates call to contract B, the logic of `B.foo()`
will be executed, but modifications will be made to state variable `A.var`.
This makes it possible to implement the "library" feature in Solidity: This makes it possible to implement the "library" feature in Solidity:
Reusable library code that can be applied to a contract's storage, e.g. in Reusable library code that can be applied to a contract's storage, e.g. in
order to implement a complex data structure. order to implement a complex data structure.