Function Types

The function type is a type composed of input and output types.

Signature

<function_signature> ::= <type_signature> "->" <type_signature> ;

Dependencies:

  • <type_signature>

The <function_signature> consists of an input type signature and an output type signature, separated by an arrow.

Note: <type_signature> also contains a tuple signature, therefore a function with multiple inputs and outputs is implicitly operating on a tuple.

Declaration

<function_declaration> ::= 
    "fn" <ident> "("
        [(<ident> ":" <type_signature>) ("," <ident> ":" <type_signature>)* [","]]
    ")" ["->" "(" <type_signature> ("," <type_signature>)* [","] ")"] ;

Dependencies:

  • <ident>
  • <type_signature>

Assignment

<function_assignment> ::= <function_declaration> <code_block> ;

Dependencies:

  • <code_block>

The <function_assignment> is defined as the "fn" keyword followed by its identifier, followed by optional comma separated pairs of identifiers and type signatures, delimited by parenthesis, then optionally followed by an arrow and a list of comma separated return types signatures delimited by parenthesis, then finally the code block of the function body.

Arrow Functions

<arrow_function> ::= (<ident> | ("(" <ident> ("," <ident>)* [","] ")")) "=>" <code_block> ;

Dependencies:

  • <ident>
  • <code_block>

The <arrow_function> is defined as either a single identifier or a comma separated, parenthesis delimited list of identifiers, followed by the "=>" bigram, followed by a code block.

Call

<function_call> ::= <ident> "(" [<expr> ("," <expr>) [","]] ")" ;

Dependencies:

  • <ident>
  • <expr>

The <function_call> is an identifier followed by a comma separated list of expressions delimited by parenthesis.

Semantics

todo