Signature

Description

Property Lists

<player>

Value Syntax

GlobalDataDef:

The syntax for the Signature property in a GlobalDataDef player is a single <identifier> or "string" surrounded by parentheses.

GlobalDataUse:

The syntax for the Signature property in a GlobalDataUse player is a single <identifier> or "string" surrounded by parentheses.

ReadFile:

The syntax for the Signature property in a ReadFile player is a list of items that are either <identifier>s or "string"s, surrounded by parentheses.

RoutineCall:

The syntax for the Signature property in a RoutineCall player consists of two fields, separated by a semicolon, surrounded by parentheses. Each of the fields is optional, yet one of them must be specified. The first field is a comma-separated list of items that are either <identifier>s or "string"s. The second field is a single <identifier> or "string". If the first field is omitted, the semicolon is required. If the second field is omitted, the semicolon must not be present.

RoutineDef:

The syntax for the Signature property in a RoutineDef player consists of two fields, separated by a semicolon, surrounded by parentheses. Each of the fields is optional, yet one of them must be specified. The first field is a comma-separated list of items that are either
<identifier>s or "string"s. The second field is a single <identifier> or "string". If the first field is omitted, the semicolon is required. If the second field is omitted, the semicolon must not be present.

RPCCall:

The syntax for the Signature property in an RPCCall player consists of two fields, separated by a semicolon, surrounded by parentheses. Each of the fields is optional, yet one of them must be specified. The first field is a list of items that are either <identifier>s or "string"s. The second field is a single <identifier> or "string". If the first field is omitted, the semicolon is required. If the second field is omitted, the semicolon must not be present.

RPCDef:

The syntax for the Signature property in an RPCDef player consists of two fields, separated by a semicolon, surrounded by parentheses. Each of the fields is optional, yet one of them must be specified. The first field is a list of items that are either <identifier>s or "string"s. The second field is a single <identifier> or "string". If the first field is omitted, the semicolon is required. If the second field is omitted, the semicolon must not be present.

StreamIn:

The syntax for the Signature property in a StreamIn player is a single <identifier> or "string", surrounded by parentheses.

StreamOut:

The syntax for the Signature property in a StreamOut player is a single <identifier> or "string", surrounded by parentheses.

WriteFile:

The syntax for the Signature property in a WriteFile player is a list of items that are either <identifier>s or "string"s, surrounded by parentheses.

Required Rule

There is no default value for the Signature property.

Merge Rule

Subsequent specifications of the Signature property in a single property list are reported as errors. The UniCon compiler uses the first of the duplicate Signature properties it encounters.

Semantic Checks

1. In ProcedureCall connections, the UniCon compiler compares the signature of each RoutineCall player with the signature of the RoutineDef player. The number of arguments in each signature, the data types of the arguments in corresponding positions in the argument lists, and the data types of the return values are compared. If the signatures are not identical in each comparison, UniCon reports the mismatches as errors.
   
   
2. In RemoteProcCall connections, the UniCon compiler compares the signature of each RPCCall player with the signature of the RPCDef player. The number of arguments in each signature, the data types of the arguments in corresponding positions in the argument lists, and the data types of the return values are compared. If the signatures are not identical in each comparison, UniCon reports the mismatches as errors.
   
   
3. In DataAccess connections, the UniCon compiler compares the signature of each GlobalDataUse player with the signature of the GlobalDataDef player. The data type constituting the signature in each player is compared. If the signatures are not identical, UniCon reports the mismatch as an error.
   
   
4. In Pipe connections, the UniCon compiler connects StreamIn players to StreamOut players, StreamIn players to ReadNext players, and StreamOut players to WriteNext players. In the first case, the data type constituting the signature of the StreamIn player is compared with the data type of the StreamOut player. In the other two cases, the data type of the StreamIn or StreamOut player is compared with the first data type in the list of data types in the RecordFormat property of the component containing the ReadNext or WriteNext player. If the data types are not identical, UniCon reports the mismatch as an error.
   
   

Example

  PLAYER input_data_stream IS StreamIn
    SIGNATURE ("line")
  END input_data_stream

  PLAYER output_data_stream IS StreamOut
    SIGNATURE ("line")
  END output_data_stream

  PLAYER global_variable IS GlobalDataDef
    SIGNATURE ("int")
  END global_variable

  PLAYER global_variable IS GlobalDataUse
    SIGNATURE ("int")
  END global_variable

  PLAYER local_routine IS RoutineCall
    SIGNATURE ("int", "char *"; "void")
  END local_routine

  PLAYER local_routine IS RoutineDef
    SIGNATURE ("int", "char *"; "void")
  END local_routine

  PLAYER remote_routine IS RPCCall
    SIGNATURE ("int", "double"; "void")
  END remote_routine

  PLAYER remote_routine IS RPCDef
    SIGNATURE ("int", "double"; "void")
  END remote_routine

  PLAYER read IS ReadFile
    SIGNATURE ("line")
  END read

  PLAYER write IS WriteFile
    SIGNATURE ("line")
  END write

Author: Gregory Zelesnik

Last Modified: May 12, 1996