Determines if a struct is declared yet.

The declaration of a struct extends to the entire process execution, and prevails at the end of the XSQL-script in which has been declared. Consequently, if this XSQL-script is recursively called, without taking into account if the struct has been previously declared, through the second iteration will produce an error of struct already defined.

For this reason, it is recommended that all declaration of a susceptible structure to be declared several times in a same execution, will be encapsulated inside of the isDeclared tag.

1 struct.isDeclared

<struct.isDeclared type='type'/>

Attributes
Name	Type	Required	Default	Description
Atype	String				Struct name.

Returns
Type	Description
boolean	[True] If the struct is already declared. [False] If it has not yet been declared.

Exceptions

attribute 'type' required

The struct name has not been specified.

Example

Declaration of a struct, controlling that has not been previously declared.

Copy

<xsql-script name='struct_isDeclared_point2d'>
    <body>
        <if>
            <expr>
                <not><struct.isDeclared type='point2d' /></not>
            </expr>
            <then>
                <struct.declare type='point2d'>
                    <field name='x' type='double' />
                    <field name='y' type='double' />
                </struct.declare>
            </then>
        </if>
    </body>
</xsql-script>