5.8.1. Formal Parameters

5.8.1. Formal Parameters
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	Description
	Formal parameters define the interface of a graph pattern by a list of pattern variables.

	Syntax
FormalParamsAST ::= PatternVariableDefAST \| FormalParamsAST , PatternVariableDefAST Formal parameters is a list of pattern variables separated by commas. It can contain an arbitrary number of variables (including none).

Syntax

FormalParamsAST ::= PatternVariableDefAST 
                  | FormalParamsAST , PatternVariableDefAST

Formal parameters is a list of pattern variables separated by commas. It can contain an arbitrary number of variables (including none).

	Semantics
	In case of formal parameters the direction of the parameters is not defined (in contrast to the directed formal parameters). The variables can be used both for input and output purposes depending on the the invoking environment. Those variables that are bound before the invocation of the pattern are the input variables and those that are unbound are output variables.

Used By: graph pattern definition