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Merge pull request #6566 from ethereum/docs-intro-sc-storage

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[DOCS] Polish introductory section of introduction to smart contracts
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docs/introduction-to-smart-contracts.rst
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@ -31,10 +31,9 @@ Storage Example
} }
} }
The first line simply tells that the source code is written for The first line tells you that the source code is written for
Solidity version 0.4.0 or anything newer that does not break functionality Solidity version 0.4.0, or a newer version of the language up to, but not including version 0.7.0.
(up to, but not including, version 0.7.0). This is to ensure that the This is to ensure that the contract is not compilable with a new (breaking) compiler version, where it could behave differently.
contract is not compilable with a new (breaking) compiler version, where it could behave differently.
:ref:`Pragmas<pragma>` are common instructions for compilers about how to treat the :ref:`Pragmas<pragma>` are common instructions for compilers about how to treat the
source code (e.g. `pragma once <https://en.wikipedia.org/wiki/Pragma_once>`_). source code (e.g. `pragma once <https://en.wikipedia.org/wiki/Pragma_once>`_).
@ -42,9 +41,9 @@ A contract in the sense of Solidity is a collection of code (its *functions*) an
data (its *state*) that resides at a specific address on the Ethereum data (its *state*) that resides at a specific address on the Ethereum
blockchain. The line ``uint storedData;`` declares a state variable called ``storedData`` of blockchain. The line ``uint storedData;`` declares a state variable called ``storedData`` of
type ``uint`` (*u*\nsigned *int*\eger of *256* bits). You can think of it as a single slot type ``uint`` (*u*\nsigned *int*\eger of *256* bits). You can think of it as a single slot
in a database that can be queried and altered by calling functions of the in a database that you can query and alter by calling functions of the
code that manages the database. In the case of Ethereum, this is always the owning code that manages the database. In the case of Ethereum, this is always the owning
contract. And in this case, the functions ``set`` and ``get`` can be used to modify contract. In this case, the functions ``set`` and ``get`` can be used to modify
or retrieve the value of the variable. or retrieve the value of the variable.
To access a state variable, you do not need the prefix ``this.`` as is common in To access a state variable, you do not need the prefix ``this.`` as is common in
@ -53,9 +52,9 @@ other languages.
This contract does not do much yet apart from (due to the infrastructure This contract does not do much yet apart from (due to the infrastructure
built by Ethereum) allowing anyone to store a single number that is accessible by built by Ethereum) allowing anyone to store a single number that is accessible by
anyone in the world without a (feasible) way to prevent you from publishing anyone in the world without a (feasible) way to prevent you from publishing
this number. Of course, anyone could just call ``set`` again with a different value this number. Anyone could call ``set`` again with a different value
and overwrite your number, but the number will still be stored in the history and overwrite your number, but the number is still stored in the history
of the blockchain. Later, we will see how you can impose access restrictions of the blockchain. Later, you will see how you can impose access restrictions
so that only you can alter the number. so that only you can alter the number.
.. note:: .. note::
@ -64,7 +63,7 @@ so that only you can alter the number.
.. warning:: .. warning::
Be careful with using Unicode text, as similar looking (or even identical) characters can Be careful with using Unicode text, as similar looking (or even identical) characters can
have different code points and as such will be encoded as a different byte array. have different code points and as such are encoded as a different byte array.
.. index:: ! subcurrency .. index:: ! subcurrency