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# Algorand Specifications

An _application call_ transaction additionally has the following fields:

| FIELD | CODEC | TYPE | REQUIRED |
| --- | --- | --- | --- |
| Application ID | `apid` | `uint64` | Yes (except for Creation) |
| On Completion Action | `apan` | `uint64` | Yes |
| Approval Program | `apap` | `[]byte` | No |
| Clear State Program | `apsu` | `[]byte` | No |
| Reject Version | `aprv` | `uint64` | No |
| Extra Program Pages | `apep` | `uint64` | No |
| Global State Schema | `apgs` | `struct` | No |
| Local State Schema | `apls` | `struct` | No |
| Arguments | `apaa` | `[][]byte` | No |
| Foreign Accounts | `apat` | `[]address` | No |
| Foreign Applications | `apfa` | `[]uint64` | No |
| Foreign Assets | `apas` | `[]uint64` | No |
| Box References | `apbx` | `[]struct` | No |
| Access List | `al` | `[]struct` | No |

The sum of the elements in _foreign accounts_ (`apat`), _foreign applications_ (`apfa`), _foreign assets_ (`apas`), and _box references_ (`apbx`) **MUST NOT** exceed Appr,maxAppr,max.

The _application ID_ identifies the application being called.

> If the _application ID_ is omitted (zero), this transaction is _creating_ an application.

The _on completion action_ specifies an additional effect of this transaction on the application’s state in the _sender_ or _application creator’s_ account data.

The `apan` field values are enumerated as follows:

| ACTION | VALUE | EFFECT |
| --- | --- | --- |
| `NoOpOC` | `0` | _Only_ execute the Approval Program associated with this _application ID_, with no additional effects. |
| `OptInOC` | `1` | _Before_ executing the Approval Program, allocate _local state_ for this _application ID_ into the _sender_’s account data. |
| `CloseOutOC` | `2` | _After_ executing the Approval Program, clear any _local state_ for this _application ID_ out of the _sender_’s account data. |
| `ClearStateOC` | `3` | _Do not_ execute the Approval Program, and instead execute the Clear State Program (which may not reject this transaction). Additionally, clear any _local state_ for this _application ID_ out of the _sender_’s account data (as in `CloseOutOC`). |
| `UpdateApplicationOC` | `4` | _After_ executing the Approval Program, _replace_ the Approval Program and Clear State Program associated with this _application ID_ with the programs specified in this transaction. |
| `DeleteApplicationOC` | `5` | _After_ executing the Approval Program, _delete_ the parameters of with this _application ID_ from the account data of the application’s creator. |

The _approval program_ ( **OPTIONAL**) contains the approval program bytecode.

> This field is used for _application creation_ and _updates_, and sets the corresponding application’s Approval Program.

The _clear state program_ ( **OPTIONAL**) contains the clear state program bytecode.

> This field is used for _application creation_ and _updates_, and sets the corresponding application’s Clear State Program.

- The Approval Program and the Clear State Program **MUST** have the same version number if either is 66 or higher.

The _reject version_ ( **OPTIONAL**), if set to a positive number, specifies that the application call **MUST** fail unless the reject version value exceeds the Application Version.

> For further details on Application Versions, refer to the [Applications Specifications](https://specs.algorand.co/ledger/ledger-applications).

A _program page_ ( **OPTIONAL**) is a chunk of application program bytecode. The _extra program pages_ define the number of _program pages_ besides the first one.

> This field is only used during _application creation_, and requests an increased maximum size for the Approval Program or Clear State Program.

- There **MUST NOT** be more than Apppage,maxApppage,max _extra program_ pages,

- The _program page_ byte length **MUST NOT** exceed Appprog,maxAppprog,max.

The _global state schema_ ( **OPTIONAL**) defines the _global_ state allocated into the creator account that of the _application ID_.

The _global state schema_ is a structure containing:

| FIELD | CODEC | TYPE | DESCRIPTION |
| --- | --- | --- | --- |
| Number of Uints | `nui` | `uint64` | The number of _global_ 64-bit unsigned integer variables for the application. |
| Number of Bytes | `nbs` | `uint64` | The number of _global_ byte-array variables for the application. |

> This field is only used during _application creation_, and sets bounds on the size of the _global state_ associated with this application.

- There **MUST NOT** be more than AppGS,maxAppGS,max _global_ variables for the application.

TODO: Restrictions on key-value lengths

The _local state schema_ ( **OPTIONAL**) defines the _local_ state allocated into the accounts that opt-in the _application ID_.

The _local state schema_ is a structure containing:

| FIELD | CODEC | TYPE | DESCRIPTION |
| --- | --- | --- | --- |
| Number of Uints | `nui` | `uint64` | The number of _local_ 64-bit unsigned integer variables for the application. |
| Number of Bytes | `nbs` | `uint64` | The number of _local_ byte-array variables for the application. |

> This field is only used during _application creation_, and sets bounds on the size of the _local state_ for accounts that opt in to this application.

- There **MUST NOT** be more than AppLS,maxAppLS,max _local_ variables for the application.

TODO: Restrictions on key-value lengths

The _application arguments_ ( **OPTIONAL**) list provides byte-array arguments to the application being called.

- There **MUST NOT** be more than Apparg,maxApparg,max entries in this list,

- The sum of their byte lengths **MUST NOT** exceed Appay,maxAppay,max.

The _foreign accounts_ ( **OPTIONAL**) list specifies the _accounts_, besides the _sender_, whose _local states_ **MAY** be referred to by executing the Approval Program or the Clear State Program. These accounts are referred to by their 32-byte addresses.

- There **MUST NOT** be more than Appacc,maxAppacc,max entries in this list.

The _foreign applications_ ( **OPTIONAL**) list specifies the _application IDs_, besides the application whose Approval Program or Clear State Program is executing, that the executing program **MAY** read _global state_ from. These applications are referred to by their 64-bit unsigned integer IDs.

- There **MUST NOT** be more than Appapp,maxAppapp,max entries in this list.

The _foreign assets_ ( **OPTIONAL**) list specifies the _asset IDs_ from which the executing Approval Program or Clear State Program **MAY** read _asset parameters_. These assets are referred to by their 64-bit unsigned integer IDs.

- There **MUST NOT** be more than Appasa,maxAppasa,max entries in this list.

The _box references_ ( **OPTIONAL**) list specifies the _boxes_ that the executing Approval Program (with AVM Version 9 or later), or any other Approval Program in the same group, **MAY** access for reading or writing when the _box reference_ matches the running program _application IDs_.

Each element of the _box reference_ encodes a structure containing:

| FIELD | CODEC | TYPE | DESCRIPTION |
| --- | --- | --- | --- |
| Index | `i` | `uint64` | A 11-based index in the _foreign applications_ (`apfa`) list. |
| Name | `n` | `[]byte` | The box identifier. |

An omitted index (`i`) is interpreted as the _application ID_ of this transaction (`apid`, or the ID allocated for the created application when `apid` is 00).

- There **MUST NOT** be more than AppBox,maxAppBox,max entries in this list.

- The _box name_ byte length **MUST NOT** exceed Appk,maxAppk,max.

The _access list_ ( **OPTIONAL**) specifies _resources_ ( _accounts_, _application_ IDs_, _asset IDs_, and _box references_) that the executing Approval Program (with AVM Version 9 or later), or any other Approval Program in the same group, **MAY** access for reading or writing.

Each element of the _access list_ encodes one of the following resources:

| FIELD | CODEC | TYPE | DESCRIPTION |
| --- | --- | --- | --- |
| Address | `d` | `[]byte` | An Account |
| Asset | `s` | `uint64` | An Asset ID |
| Application | `p` | `uint64` | An Application ID |
| Holding | `h` | `struct` | A Holding contains subfields `d` and `s` that refer to the Address and Asset of the Holding, respectively. |
| Locals | `l` | `struct` | A Local contains subfields `d` and `p` that refer to the Address and Application of the Local State, respectively. |
| Box Reference | `b` | `struct` | A Box Reference contains subfields `i` and `n`, that refer to the Application and Box Name, respectively. |

The subfields of `h`, `l`, `b` refer to Accounts, Assets, and Applications by using an 11-based index into the Access List.

An omitted `d` indicates the _sender_ of the transaction.

An omitted app (`p` or `i`) indicates the called Application.

The _access list_ **MUST** be empty if any of the _foreign arrays_ (`apat`, `apfa`, `apas`), or _box reference_ list (`apbx`) fields are populated.

- There **MUST NOT** be more than Appaccess,maxAppaccess,max entries in this list.

TODO

TODO