class Crystal::Macros::FunDef

Overview

A function declaration inside a lib, or a top-level C function definition.

Every function node is equivalent to:

fun {{ node.name }} {% if real_name = node.real_name %}= {{ real_name }}{% end %}(
  {% for arg in node.args %} {{ arg }}, {% end %}
  {% if node.variadic? %} ... {% end %}
) {% if return_type = node.return_type %}: {{ return_type }}{% end %}
{% if node.has_body? %}
  {{ body }}
end
{% end %}

Defined in:

compiler/crystal/macros.cr

Instance Method Summary

Instance methods inherited from class Crystal::Macros::ASTNode

!=(other : ASTNode) : BoolLiteral !=, ==(other : ASTNode) : BoolLiteral ==, class_name : StringLiteral class_name, column_number : StringLiteral | NilLiteral column_number, doc : StringLiteral doc, doc_comment : MacroId doc_comment, end_column_number : StringLiteral | NilLiteral end_column_number, end_line_number : StringLiteral | NilLiteral end_line_number, filename : StringLiteral | NilLiteral filename, id : MacroId id, is_a?(type : TypeNode) : BoolLiteral is_a?, line_number : StringLiteral | NilLiteral line_number, nil? : BoolLiteral nil?, raise(message) : NoReturn raise, stringify : StringLiteral stringify, symbolize : SymbolLiteral symbolize, warning(message : StringLiteral) : NilLiteral warning

Instance Method Detail

def args : ArrayLiteral(Arg) #

Returns the parameters of the function.

This does not include the variadic parameter.


[View source]
def body : ASTNode | Nop #

Returns the body of the function, if any.

Both top-level funs and lib funs may return a Nop. Instead, #has_body? can be used to distinguish between the two.

macro body_class(x)
  {{ (x.is_a?(LibDef) ? x.body : x).body.class_name }}
end

body_class(lib MyLib
  fun foo
end) # => "Nop"

body_class(fun foo
end) # => "Nop"

[View source]
def has_body? : BoolLiteral #

Returns whether this function has a body.

Top-level funs have a body, whereas lib funs do not.

macro has_body(x)
  {{ (x.is_a?(LibDef) ? x.body : x).has_body? }}
end

has_body(lib MyLib
  fun foo
end) # => false

has_body(fun foo
end) # => true

[View source]
def name : MacroId #

Returns the name of the function in Crystal.


[View source]
def real_name : StringLiteral | Nop #

Returns the real C name of the function, if any.


[View source]
def return_type : ASTNode | Nop #

Returns the return type of the function, if specified.


[View source]
def variadic? : BoolLiteral #

Returns whether the function is variadic.


[View source]