Model Syntax

A dfn is written as a sequence of one or more statements, separated by newlines or the diamond (⋄) character and enclosed in braces ({}). A dop takes the same form, and additionally refers to its operands. The arguments and operands are referred to by a fixed set of names rather than being declared in a header:

These names are described under Arguments.

In its simplest form, a dfn is a single expression:

      {(+/⍵)÷≢⍵} 1 2 3 4
2.5

A dfn is a value like any other function, so it can be named by ordinary assignment or used anonymously:

      mean←{(+/⍵)÷≢⍵}
      mean 1 2 3 4
2.5

A dfn is ambivalent, and its valence is not declared: its valence is inferred from whether the body refers to ⍺, and whether the dfn is applied with one argument or two. When a dfn that refers to ⍺ is called monadically, ⍺ has no value until a statement beginning ⍺← supplies a default left argument. Similarly, a dop is a monadic or dyadic operator according to whether it refers to ⍵⍵.

See Statements for information on the layout of multi-line dfns and Multi-line Dfns for the role of each line within such statements.