Class: ActionDispatch::Journey::GTG::Builder
- Inherits:
-
Object
- Object
- ActionDispatch::Journey::GTG::Builder
- Defined in:
- lib/action_dispatch/journey/gtg/builder.rb
Overview
:nodoc:
Constant Summary collapse
Instance Attribute Summary collapse
-
#ast ⇒ Object
readonly
Returns the value of attribute ast.
-
#endpoints ⇒ Object
readonly
Returns the value of attribute endpoints.
-
#root ⇒ Object
readonly
Returns the value of attribute root.
Instance Method Summary collapse
- #firstpos(node) ⇒ Object
- #followpos(node) ⇒ Object
-
#initialize(root) ⇒ Builder
constructor
A new instance of Builder.
- #lastpos(node) ⇒ Object
- #nullable?(node) ⇒ Boolean
- #transition_table ⇒ Object
Constructor Details
Instance Attribute Details
#ast ⇒ Object (readonly)
Returns the value of attribute ast.
9 10 11 |
# File 'lib/action_dispatch/journey/gtg/builder.rb', line 9 def ast @ast end |
#endpoints ⇒ Object (readonly)
Returns the value of attribute endpoints.
9 10 11 |
# File 'lib/action_dispatch/journey/gtg/builder.rb', line 9 def endpoints @endpoints end |
#root ⇒ Object (readonly)
Returns the value of attribute root.
9 10 11 |
# File 'lib/action_dispatch/journey/gtg/builder.rb', line 9 def root @root end |
Instance Method Details
#firstpos(node) ⇒ Object
82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 |
# File 'lib/action_dispatch/journey/gtg/builder.rb', line 82 def firstpos(node) case node when Nodes::Star firstpos(node.left) when Nodes::Cat if nullable?(node.left) firstpos(node.left) | firstpos(node.right) else firstpos(node.left) end when Nodes::Or node.children.map { |c| firstpos(c) }.flatten.uniq when Nodes::Unary firstpos(node.left) when Nodes::Terminal nullable?(node) ? [] : [node] else raise ArgumentError, 'unknown firstpos: %s' % node.class.name end end |
#followpos(node) ⇒ Object
124 125 126 |
# File 'lib/action_dispatch/journey/gtg/builder.rb', line 124 def followpos(node) followpos_table[node] end |
#lastpos(node) ⇒ Object
103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 |
# File 'lib/action_dispatch/journey/gtg/builder.rb', line 103 def lastpos(node) case node when Nodes::Star firstpos(node.left) when Nodes::Or node.children.map { |c| lastpos(c) }.flatten.uniq when Nodes::Cat if nullable?(node.right) lastpos(node.left) | lastpos(node.right) else lastpos(node.right) end when Nodes::Terminal nullable?(node) ? [] : [node] when Nodes::Unary lastpos(node.left) else raise ArgumentError, 'unknown lastpos: %s' % node.class.name end end |
#nullable?(node) ⇒ Boolean
63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 |
# File 'lib/action_dispatch/journey/gtg/builder.rb', line 63 def nullable?(node) case node when Nodes::Group true when Nodes::Star true when Nodes::Or node.children.any? { |c| nullable?(c) } when Nodes::Cat nullable?(node.left) && nullable?(node.right) when Nodes::Terminal !node.left when Nodes::Unary nullable?(node.left) else raise ArgumentError, 'unknown nullable: %s' % node.class.name end end |
#transition_table ⇒ Object
17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 |
# File 'lib/action_dispatch/journey/gtg/builder.rb', line 17 def transition_table dtrans = TransitionTable.new marked = {} state_id = Hash.new { |h,k| h[k] = h.length } start = firstpos(root) dstates = [start] until dstates.empty? s = dstates.shift next if marked[s] marked[s] = true # mark s s.group_by { |state| symbol(state) }.each do |sym, ps| u = ps.map { |l| followpos(l) }.flatten next if u.empty? if u.uniq == [DUMMY] from = state_id[s] to = state_id[Object.new] dtrans[from, to] = sym dtrans.add_accepting(to) ps.each { |state| dtrans.add_memo(to, state.memo) } else dtrans[state_id[s], state_id[u]] = sym if u.include?(DUMMY) to = state_id[u] accepting = ps.find_all { |l| followpos(l).include?(DUMMY) } accepting.each { |accepting_state| dtrans.add_memo(to, accepting_state.memo) } dtrans.add_accepting(state_id[u]) end end dstates << u end end dtrans end |