class

Crystal::Macros::FunDef

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 %}

Instance methods

args

Returns the parameters of the function.

This does not include the variadic parameter.

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body

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"

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has_body?

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

Source

name

Returns the name of the function in Crystal.

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real_name

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

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return_type

Returns the return type of the function, if specified.

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variadic?

Returns whether the function is variadic.

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