Class: Paru::PandocFilter::Metadata

Inherits:
Hash
  • Object
show all
Defined in:
lib/paru/filter/metadata.rb

Overview

A Metadata object is a Ruby Hash representation of a pandoc metadata node.

Instance Method Summary collapse

Constructor Details

#initialize(contents = {}) ⇒ Metadata

Create a new Metadata object based on the contents.

Parameters:

  • contents (MetaMap|String|Hash) (defaults to: {}) —

    the initial contents of this metadata. If contents is a String, it is treated as a YAML string and converted to a Hash first.

Raises:

  • Error when converting contents to a Hash fails



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# File 'lib/paru/filter/metadata.rb', line 36

def initialize(contents = {})
    if not contents.is_a? Hash
        # If not a Hash, it is either a YAML string or can be
        # converted to a YAML string
        if contents.is_a? PandocFilter::MetaMap
            yaml_string = meta2yaml contents
        elsif contents.is_a? String
            yaml_string = contents
        else
            raise FilterError.new("Expected a Hash, MetaMap, or String, got '#{contents}' instead.")
        end

        # Try to convert the YAML string to a Hash
        if yaml_string.empty?
            contents = {}
        else
            contents = YAML.safe_load yaml_string, permitted_classes: [Date]
        end

        if not contents
            # Error parsing YAML
            raise FilterError.new("Unable to convert YAML string '#{yaml_string}' to a Hash.")
        end
    end

    # Merge the contents with this newly created Metadata
    contents.each do |key, value|
        self[key] = value
    end
end

Instance Method Details

#to_meta ⇒ Meta

Convert this Metadata to a pandoc AST representation of metadata: Paru::PandocFilter::Meta

Returns:



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# File 'lib/paru/filter/metadata.rb', line 71

def to_meta()
    if self.empty?
        PandocFilter::Meta.new {}
    else
        begin
            yaml_string = "#{clean_hash.to_yaml}..."
            yaml2json = Paru::Pandoc.new {from "markdown"; to "json"}
            json_string = yaml2json << yaml_string
            meta_doc = PandocFilter::Document.from_JSON json_string
            meta_doc.meta
        rescue
        end
    end
end