Class: SyntaxTree::Mermaid::FlowChart

Inherits:
Object
  • Object
show all
Defined in:
lib/syntax_tree/mermaid.rb

Overview

This is the main class that handles rendering a flowchart. It keeps track of its nodes and links and renders them according to the mermaid syntax.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ FlowChart

Returns a new instance of FlowChart.



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# File 'lib/syntax_tree/mermaid.rb', line 15

def initialize
  @output = StringIO.new
  @output.puts("flowchart TD")
  @prefix = "  "

  @nodes = {}
  @links = []
end

Instance Attribute Details

Returns the value of attribute links.



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# File 'lib/syntax_tree/mermaid.rb', line 13

def links
  @links
end

#nodes ⇒ Object (readonly)

Returns the value of attribute nodes.



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# File 'lib/syntax_tree/mermaid.rb', line 13

def nodes
  @nodes
end

#output ⇒ Object (readonly)

Returns the value of attribute output.



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# File 'lib/syntax_tree/mermaid.rb', line 13

def output
  @output
end

#prefix ⇒ Object (readonly)

Returns the value of attribute prefix.



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# File 'lib/syntax_tree/mermaid.rb', line 13

def prefix
  @prefix
end

Instance Method Details

#fetch(id) ⇒ Object

Retrieve a node that has already been added to the flowchart by its id.



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# File 'lib/syntax_tree/mermaid.rb', line 25

def fetch(id)
  nodes.fetch(id)
end

#link(from, to, label = nil, type: :directed, color: nil) ⇒ Object

Add a link to the flowchart between two nodes with an optional label.



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# File 'lib/syntax_tree/mermaid.rb', line 30

def link(from, to, label = nil, type: :directed, color: nil)
  link = Link.new(from, to, label, type, color)
  links << link

  output.puts("#{prefix}#{link.render}")
  link
end

#node(id, label = " ", shape: :rectangle) ⇒ Object

Add a node to the flowchart with an optional label.



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# File 'lib/syntax_tree/mermaid.rb', line 39

def node(id, label = " ", shape: :rectangle)
  node = Node.new(id, label, shape)
  nodes[id] = node

  output.puts("#{prefix}#{nodes[id].render}")
  node
end

#render ⇒ Object

Return the rendered flowchart.



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# File 'lib/syntax_tree/mermaid.rb', line 64

def render
  links.each_with_index do |link, index|
    if link.color
      output.puts("#{prefix}linkStyle #{index} stroke:#{link.color}")
    end
  end

  output.string
end

#subgraph(label) ⇒ Object

Add a subgraph to the flowchart. Within the given block, all of the nodes will be rendered within the subgraph.



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# File 'lib/syntax_tree/mermaid.rb', line 49

def subgraph(label)
  output.puts("#{prefix}subgraph #{Mermaid.escape(label)}")

  previous = prefix
  @prefix = "#{prefix}  "

  begin
    yield
  ensure
    @prefix = previous
    output.puts("#{prefix}end")
  end
end