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ffea3977f0
Per [XLS-0095](https://xls.xrpl.org/xls/XLS-0095-rename-rippled-to-xrpld.html), we are taking steps to rename ripple(d) to xrpl(d). This change modifies the system name from `rippled` to `xrpld`. The system name is used in limited places: * When no explicit config file is passed via the `--config` flag, then the system name is used to construct the path where the config file and database may be stored, via the `$XDG_CONFIG_HOME` and `$XDG_DATA_HOME` directories, respectively. * It is used in the metadata and user-agent as part of RPC calls. * It is newly used in the full version string.
protocol
Classes and functions for handling data and values associated with the XRP Ledger protocol.
Serialized Objects
Objects transmitted over the network must be serialized into a canonical format. The prefix "ST" refers to classes that deal with the serialized format.
The term "Tx" or "tx" is an abbreviation for "Transaction", a commonly occurring object type.
Optional Fields
Our serialized fields have some "type magic" to make optional fields easier to read:
- The operation
x[sfFoo]means "return the value of 'Foo' if it exists, or the default value if it doesn't." - The operation
x[~sfFoo]means "return the value of 'Foo' if it exists, or nothing if it doesn't." This usage of the tilde/bitwise NOT operator is not standard outside of therippledcodebase.- As a consequence of this,
x[~sfFoo] = y[~sfFoo]assigns the value of Foo from y to x, including omitting Foo from x if it doesn't exist in y.
- As a consequence of this,
Typically, for things that are guaranteed to exist, you use
x[sfFoo] and avoid having to deal with a container that may
or may not hold a value. For things not guaranteed to exist,
you use x[~sfFoo] because you want such a container. It
avoids having to look something up twice, once just to see if
it exists and a second time to get/set its value.
(Real example)
The source of this "type magic" is in SField.h.