********************************
Layout of a Solidity Source File
********************************

Source files can contain an arbitrary number of contract definitions and include directives.

.. index:: source file, ! import

Importing other Source Files
============================


Other source files can be referenced using `import "filename";` and the symbols
defined there will also be available in the current source file.

.. warning::

    Import will not work automatically for the commandline-compiler.
    Furthermore, this system of importing other files is not completely fleshed out
    yet, so please expect changes.

The `browser-based compiler <https://chriseth.github.io/browser-solidity>`_
has quite advanced support for multiple files and can even import files
directly from github, by using e.g.
```import "github.com/ethereum/dapp-bin/library/iterable_mapping.sol";```

If you want to use multiple source files with the (commandline compiler)[../commandline-compiler/] solc,
you have to specify all files you will use as arguments to solc,
the compiler will not yet search your filesystem on its own.

.. index:: ! comment, natspec

Comments
========

Single-line comments (`//`) and multi-line comments (`/*...*/`) are possible.

There are special types of comments called natspec comments
(documentation yet to be written). These are introduced by 
triple-slash comments (`///`) or using double asterisks (`/** ... */`).
Right in front of function declarations or statements,
you can use doxygen-style tags inside them to document functions, annotate conditions for formal
verification and provide a **confirmation text** that is shown to users if they want to
invoke a function.