Signature Statement :Signature

:Signature <rslttype←><name><arg1type arg1name>,...

This statement identifies the name and signature by which a function is exported as a method to be called from outside Dyalog APL. Several :Signature statements may be specified to allow the method to be called with different arguments and/or to specify a different result type.

Element	Description
rslttype	Specifies the data type for the result of the method
name	Specifies the name of the exported method.
argntype	Specifies the data type of the nth parameter
argnname	Specifies the name of the nth parameter

Argument and result data types are identified by the names of .NET Types which are defined in the .NET Assemblies specified by ⎕USING or by a :USING statement.

Examples

In the following examples, it is assumed that the .NET Search Path (defined by :Using or ⎕USING includes 'System'.

The following statement specifies that the function is exported as a method named Format which takes a single parameter of type System.Object named Array. The data type of the result of the method is an array (vector) of type System.String.

      :Signature String[]←Format Object Array

The next statement specifies that the function is exported as a method named Catenate whose result is of type System.Object and which takes 3 parameters. The first parameter is of type System.Double and is named Dimension. The second is of type System.Object and is named Arg1. The third is of type System.Object and is named Arg2.

      :Signature Object←Catenate Double Dimension,...
                              ...Object Arg1, Object Arg2

The next statement specifies that the function is exported as a method named IndexGen whose result is an array of type System.Int32 and which takes 2 parameters. The first parameter is of type System.Int32 and is named N. The second is of type System.Int32 and is named Origin.

      :Signature Int32[]←IndexGen Int32 N, Int32 Origin

The next block of statements specifies that the function is exported as a method named Mix. The method has 4 different signatures; that is, it may be called with 4 different parameter/result combinations.

      :Signature Int32[,]←Mix Double Dimension, ...
            ...Int32[] Vec1, Int32[] Vec2
      :Signature Int32[,]←Mix Double Dimension,...
            ... Int32[] Vec1, Int32[] Vec2, Int32 Vec3
      :Signature Double[,]←Mix Double Dimension, ...
            ... Double[] Vec1, Double[] Vec2
      :Signature Double[,]←Mix Double Dimension, ...
            ... Double[] Vec1, Double[] Vec2, Double[] Vec3