class YAML::Builder

• YAML::Builder
• Reference
• Object

Overview

A YAML builder generates valid YAML.

A YAML::Error is raised if attempting to generate an invalid YAML (for example, if invoking #end_sequence without a matching #start_sequence)

require "yaml"

string = YAML.build do |yaml|
  yaml.mapping do
    yaml.scalar "foo"
    yaml.sequence do
      yaml.scalar 1
      yaml.scalar 2
    end
    yaml.scalar "bar"
    yaml.mapping do
      yaml.scalar "baz"
      yaml.scalar "qux"
    end
  end
end
string # => "---\nfoo:\n- 1\n- 2\nbar:\n  baz: qux\n"

Defined in:

Constructors

• .new(io : IO)

  Creates a YAML::Builder that will write to the given IO.

• .new(io : IO, &)

  Creates a YAML::Builder that will write to the given IO, invokes the block and closes the builder.

Instance Method Summary

• #alias(anchor : String) : Nil

  Emits an alias to the given anchor.

• #close

  Closes the builder, freeing up resources.

• #document(&)

  Starts a document, invokes the block, and then ends it.

• #end_document

  Ends a document.

• #end_mapping

  Ends a mapping.

• #end_sequence

  Ends a sequence.

• #end_stream

  Ends a YAML stream.

• #finalize
• #flush

  Flushes any pending data to the underlying IO.

• #mapping(anchor : String? = nil, tag : String? = nil, style : YAML::MappingStyle = YAML::MappingStyle::ANY, &)

  Starts a mapping, invokes the block, and then ends it.

• #max_nesting : Int32

  By default the maximum nesting of sequences/amppings is 99.

• #max_nesting=(max_nesting)

  By default the maximum nesting of sequences/amppings is 99.

• #merge(anchor : String) : Nil

  Emits the scalar "<<" followed by an alias to the given anchor.

• #scalar(value, anchor : String? = nil, tag : String? = nil, style : YAML::ScalarStyle = YAML::ScalarStyle::ANY)

  Emits a scalar value.

• #sequence(anchor : String? = nil, tag : String? = nil, style : YAML::SequenceStyle = YAML::SequenceStyle::ANY, &)

  Starts a sequence, invokes the block, and the ends it.

• #start_document

  Starts a document.

• #start_mapping(anchor : String? = nil, tag : String? = nil, style : YAML::MappingStyle = YAML::MappingStyle::ANY)

  Starts a mapping.

• #start_sequence(anchor : String? = nil, tag : String? = nil, style : YAML::SequenceStyle = YAML::SequenceStyle::ANY)

  Starts a sequence.

• #start_stream

  Starts a YAML stream.

• #stream(&)

  Starts a YAML stream, invokes the block, and ends it.

Constructor Detail

Instance Method Detail

require "yaml"

yaml = YAML.build do |builder|
  builder.mapping do
    builder.scalar "key"
    builder.alias "example"
  end
end

yaml # => "---\nkey: *example\n"

require "yaml"

yaml = YAML.build do |builder|
  builder.mapping do
    builder.merge "development"
  end
end

yaml # => "---\n<<: *development\n"