Class: Cigale::MacroContext

Inherits:
Exts
  • Object
show all
Defined in:
lib/cigale/macro_context.rb

Instance Method Summary collapse

Methods inherited from Exts

#asplode, #boolp, #dig, #first_pair, #toa, #toh

Constructor Details

#initialize(options) ⇒ MacroContext

Returns a new instance of MacroContext.



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# File 'lib/cigale/macro_context.rb', line 16

def initialize (options)
  @library = options[:library]
  @params = options[:params]
  @had_expansions = false
end

Instance Method Details

#expand(entity) ⇒ Object

walk tree, expand macros we find



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# File 'lib/cigale/macro_context.rb', line 30

def expand (entity)
  case entity
  when Array
    # list of things, need to expand each individually
    array = []

    entity.each do |x|
      case child = expand(x)
      when Splat
        array += child.elems
      else
        array << child
      end
    end

    array
  when Hash
    pairs = []

    entity.each do |k, v|
      case k
      when /^\.(.*)$/
        # macro call
        if expanding?
          # keep child macro as-is for later expansion
          pairs << [k, expand(v)]
        else
          splat = false
          mname = $1

          # cf. https://github.com/itchio/cigale/issues/2 for 'spec'
          if mname =~ /^\./
            mname = mname[1..-1]
            splat = true
          end

          mdef = lookup(mname)

          res = self.with_params(v).expand(mdef)
          case res
          when Hash
            if splat
              raise "Unnecessary use of splat: #{entity.inspect}"
            end
            res.each_pair { |p| pairs << p }
          when Array
            if splat
              if entity.size > 1
                raise "Invalid array splat (needs to be single-pair hash): #{entity.inspect}"
              end
              return Splat.new(res)
            else
              return res
            end
          else
            if splat
              raise "Invalid macro expansion result for splat: #{res.inspect}"
            end
            return res
          end
        end
      else
        pairs << [k, expand(v)]
      end
    end

    pairs.to_h
  else
    # not a list, not a hash
    interpolate(entity)
  end
end

#expanding? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/cigale/macro_context.rb', line 144

def expanding?
  not @params.nil?
end

#get_param(spec) ⇒ Object 



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# File 'lib/cigale/macro_context.rb', line 121

def get_param (spec)
  raise "Found param {#{spec}} outside expansion" unless expanding?

  name, type = spec.split(" ")
  if name == '*'
    return @params
  end

  res = dig(@params, name)
  raise "Unspecified param {#{name}}" if res.nil?
  res
end

#had_expansions? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/cigale/macro_context.rb', line 140

def had_expansions?
  @had_expansions
end

#interpolate(entity) ⇒ Object

given “name”



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# File 'lib/cigale/macro_context.rb', line 104

def interpolate (entity)
  return entity unless expanding?

  case entity
  when /^{([a-zA-Z0-9*\. -]*)}$/
    # just paste param verbatim — could be a string,
    # could be a hash, a list, whatever, just jam it in there.
    get_param($1)
  when String
    entity.gsub /{([a-zA-Z0-9*\. -]*)}/ do |m|
      get_param($1)
    end
  else
    entity
  end
end

#lookup(macro_name) ⇒ Object

get a macro



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# File 'lib/cigale/macro_context.rb', line 23

def lookup (macro_name)
  mdef = @library[macro_name]
  raise "Undefined macro: #{macro_name} — got #{@library.keys.inspect}" unless mdef
  mdef
end

#with_params(params) ⇒ Object 



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# File 'lib/cigale/macro_context.rb', line 134

def with_params (params)
  raise "Can't expand while expanding" if expanding?
  @had_expansions = true
  MacroContext.new(:library => @library, :params => params)
end