Module: Stupidedi::Builder::Navigation
- Included in:
- StateMachine
- Defined in:
- lib/stupidedi/builder/navigation.rb
Querying the Current Position collapse
-
#deterministic? ⇒ Boolean
Is there exactly one valid parse tree in the current state?.
-
#distance(other) ⇒ Either<Integer>
Returns the number of segments apart the current state is from the given ‘StateMachine`’s state.
- #empty? ⇒ Boolean
-
#first? ⇒ Boolean
Is this the first segment?.
-
#last? ⇒ Boolean
Is this the last segment?.
- #successors ⇒ Array<InstructionTable>
Accessing the Current Node collapse
-
#element(m, n = nil, o = nil) ⇒ Either<Zipper::AbstractCursor<Values::AbstractElementVal>>
Extracts the mth element from the current segment, if the current state is deterministic.
-
#elementn(m, n = nil, o = nil) ⇒ Either<Values::AbstractElementVal>
Extracts the mth element from the current segment, if the current state is deterministic.
-
#segment ⇒ Either<Zipper::AbstractCursor<Values::SegmentVal>>
Extracts the segment from the current state, if the current state is deterministic and positioned on a segment.
-
#segmentn ⇒ Either<Values::SegmentVal>
Extracts the segment from the current state, if the current state is deterministic and positioned on a segment.
-
#zipper ⇒ Either<Zipper::AbstractCursor<Values::AbstractVal>>
Returns the current position within the parse tree, if the current state is deterministic.
Navigating the Tree collapse
- #count(id, *elements) ⇒ Integer
- #count!(id, *elements) ⇒ Integer
-
#find(id, *elements) ⇒ Either<StateMachine>
Returns a ‘StateMachine` positioned on the next matching segment, excluding Values::InvalidSegmentVals, that satisfies the given element constraints.
-
#find!(id, *elements) ⇒ Either<StateMachine>
Returns a ‘StateMachine` positioned on the next matching segment, including Values::InvalidSegmentVals, that satisfies the given element constraints.
-
#first ⇒ Either<StateMachine>
Returns a new ‘StateMachine` positioned on the first segment in the parse tree, if there are any segments in the parse tree.
-
#iterate(id, *elements) {|| ... } ⇒ Either<Array<Object>>
Convenience method to iterate repeated occurrences of a segment by iteratively calling ‘find`.
-
#last ⇒ Either<StateMachine>
Returns a new ‘StateMachine` positioned on the last segment in the parse tree, if there are any segments in the parse tree.
-
#next(count = 1) ⇒ Either<StateMachine>
Returns a new ‘StateMachine` positioned on the next segment, if there is a next segment.
-
#parent ⇒ Either<StateMachine>
Returns a new ‘StateMachine` positioned on the first segment of the parent structure.
-
#prev(count = 1) ⇒ Either<StateMachine>
Returns a new ‘StateMachine` positioned on the previous segment, if there is a previous segment.
-
#sequence(pattern, *patterns) ⇒ Either<StateMachine>
Sequence multiple traversals together, by iteratively calling ‘find`.
Instance Method Details
#count(id, *elements) ⇒ Integer
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# File 'lib/stupidedi/builder/navigation.rb', line 436 def count(id, *elements) __count(false, id, elements) end |
#count!(id, *elements) ⇒ Integer
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# File 'lib/stupidedi/builder/navigation.rb', line 441 def count!(id, *elements) __count(true, id, elements) end |
#deterministic? ⇒ Boolean
Is there exactly one valid parse tree in the current state?
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# File 'lib/stupidedi/builder/navigation.rb', line 19 def deterministic? @active.length == 1 end |
#distance(other) ⇒ Either<Integer>
This method uses AbstractCursor#between, which assumes the two cursors point to the same tree. If that is not the case, the results are undefined.
Returns the number of segments apart the current state is from the given ‘StateMachine`’s state. Note the direction is not indicated by the return value, so ‘a.distance(b) == b.distance(a)` for all states `a` and `b`.
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# File 'lib/stupidedi/builder/navigation.rb', line 71 def distance(other) zipper.flatmap do |a| other.zipper.map do |b| a.between(b).count(&:segment?) - 1 end end end |
#element(m, n = nil, o = nil) ⇒ Either<Zipper::AbstractCursor<Values::AbstractElementVal>>
Extracts the mth element from the current segment, if the current state is deterministic. Accepts optional arguments to extract a specific occurrence of a repeated element and/or a specific component from a composite element.
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# File 'lib/stupidedi/builder/navigation.rb', line 122 def element(m, n = nil, o = nil) segment.flatmap do |s| unless m >= 1 raise ArgumentError, "argument must be positive" end if s.node.invalid? # InvalidSegmentVal doesn't have child AbstractElementVals, its # children are SimpleElementTok, CompositeElementTok, etc, which # are not parsed values. return Either.failure("invalid segment") end designator = s.node.id.to_s definition = s.node.definition length = definition.element_uses.length unless m <= length raise ArgumentError, "#{designator} segment has only #{length} elements" end designator = designator + "%02d" % m value = s.child(m - 1) if n.nil? return Either.success(value) elsif value.node.repeated? unless n >= 1 raise ArgumentError, "argument must be positive" end limit = value.node.usage.repeat_count unless limit.include?(n) raise ArgumentError, "#{designator} can only occur #{limit.max} times" end unless value.node.children.defined_at?(n - 1) return Either.failure("#{designator} occurs only #{value.node.children.length} times") end value = value.child(n - 1) n, o = o, nil return Either.success(value) if n.nil? end unless value.node.composite? raise ArgumentError, "#{designator} is a simple element" end unless o.nil? raise ArgumentError, "#{designator} is a non-repeatable composite element" end unless n >= 1 raise ArgumentError, "argument must be positive" end length = definition.element_uses.at(m - 1).definition.component_uses.length unless n <= length raise ArgumentError, "#{designator} has only #{length} components" end if value.node.empty? Either.failure("#{designator} is empty") else Either.success(value.child(n - 1)) end end end |
#elementn(m, n = nil, o = nil) ⇒ Either<Values::AbstractElementVal>
Extracts the mth element from the current segment, if the current state is deterministic. Accepts optional arguments to extract a specific occurrence of a repeated element and/or a specific component from a composite element.
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# File 'lib/stupidedi/builder/navigation.rb', line 207 def elementn(m, n = nil, o = nil) element(m, n, o).map(&:node) end |
#empty? ⇒ Boolean
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# File 'lib/stupidedi/builder/navigation.rb', line 23 def empty? value = @active.head.node.zipper until value.root? value = value.up end value.node.children.empty? end |
#find(id, *elements) ⇒ Either<StateMachine>
Returns a ‘StateMachine` positioned on the next matching segment, excluding Values::InvalidSegmentVals, that satisfies the given element constraints. The search space is limited to certain related elements described in [Navigating.md]
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# File 'lib/stupidedi/builder/navigation.rb', line 418 def find(id, *elements) __find(false, id, elements) end |
#find!(id, *elements) ⇒ Either<StateMachine>
Returns a ‘StateMachine` positioned on the next matching segment, including Values::InvalidSegmentVals, that satisfies the given element constraints. The search space is limited to certain related elements described in [Navigating.md]
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# File 'lib/stupidedi/builder/navigation.rb', line 431 def find!(id, *elements) __find(true, id, elements) end |
#first ⇒ Either<StateMachine>
Returns a new ‘StateMachine` positioned on the first segment in the parse tree, if there are any segments in the parse tree.
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# File 'lib/stupidedi/builder/navigation.rb', line 218 def first active = roots.map do |zipper| state = zipper value = zipper.node.zipper until value.node.segment? or value.leaf? value = value.down state = state.down end unless value.node.segment? return Either.failure("no segments") end # Synchronize the two parallel state and value nodes unless value.eql?(state.node.zipper) state = state.replace(state.node.copy(:zipper => value)) end state end Either.success(StateMachine.new(@config, active)) end |
#first? ⇒ Boolean
Is this the first segment?
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# File 'lib/stupidedi/builder/navigation.rb', line 34 def first? value = @active.head.node.zipper until value.root? return false unless value.first? value = value.up end return true end |
#iterate(id, *elements) {|| ... } ⇒ Either<Array<Object>>
Convenience method to iterate repeated occurrences of a segment by iteratively calling ‘find`. Beware this doesn’t check that the segment is allowed to repeat, so calling ‘iterate(:XYZ)` may yield an `XYZ` segment and then throw an exception when searching for the second, if `XYZ` is not repeatable.
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# File 'lib/stupidedi/builder/navigation.rb', line 454 def iterate(id, *elements) a = [] m = find(id, *elements) return m unless m.defined? while m.defined? m = m.flatmap do |n| a << yield(n) n.find(id, *elements) end end Either.success(a) end |
#last ⇒ Either<StateMachine>
Returns a new ‘StateMachine` positioned on the last segment in the parse tree, if there are any segments in the parse tree.
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# File 'lib/stupidedi/builder/navigation.rb', line 247 def last active = roots.map do |zipper| state = zipper value = zipper.node.zipper until value.node.segment? or value.leaf? value = value.down.last state = state.down.last end unless value.node.segment? return Either.failure("no segments") end # Synchronize the two parallel state and value nodes unless value.eql?(state.node.zipper) state = state.replace(state.node.copy(:zipper => value)) end state end Either.success(StateMachine.new(@config, active)) end |
#last? ⇒ Boolean
Is this the last segment?
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# File 'lib/stupidedi/builder/navigation.rb', line 46 def last? value = @active.head.node.zipper until value.root? return false unless value.last? value = value.up end return true end |
#next(count = 1) ⇒ Either<StateMachine>
Returns a new ‘StateMachine` positioned on the next segment, if there is a next segment. Optionally, a `count` argument may be provided that indicates how many segments to advance.
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# File 'lib/stupidedi/builder/navigation.rb', line 324 def next(count = 1) unless count > 0 raise ArgumentError, "count must be positive" end active = @active.map do |zipper| state = zipper value = zipper.node.zipper count.times do while not value.root? and value.last? value = value.up state = state.up end if value.root? return Either.failure("cannot move to next after last segment") end value = value.next state = state.next until value.node.segment? value = value.down state = state.down end end # Synchronize the two parallel state and value nodes unless value.eql?(state.node.zipper) state = state.replace(state.node.copy(:zipper => value)) end state end Either.success(StateMachine.new(@config, active)) end |
#parent ⇒ Either<StateMachine>
Returns a new ‘StateMachine` positioned on the first segment of the parent structure. For example, when the current segment belongs to a loop but it’s not the first segment in that loop, this method will rewind to the first segment in the loop. If the current position is the first segment of a loop, this method will rewind to the first segment in the loop’s parent structure.
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# File 'lib/stupidedi/builder/navigation.rb', line 280 def parent active = [] @active.each do |zipper| state = zipper value = zipper.node.zipper while value.first? and not value.root? value = value.up state = state.up end if value.root? break end value = value.first state = state.first until value.node.segment? value = value.down state = state.down end # Synchronize the two parallel state and value nodes unless value.eql?(state.node.zipper) state = state.replace(state.node.copy(:zipper => value)) end active << state end if active.empty? Either.failure("no parent segment") else Either.success(StateMachine.new(@config, active)) end end |
#prev(count = 1) ⇒ Either<StateMachine>
Returns a new ‘StateMachine` positioned on the previous segment, if there is a previous segment. Optionally, a `count` argument may be provided that indicates how many segments to rewind.
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# File 'lib/stupidedi/builder/navigation.rb', line 369 def prev(count = 1) unless count > 0 raise ArgumentError, "count must be positive" end active = @active.map do |zipper| state = zipper value = zipper.node.zipper count.times do while not value.root? and value.first? value = value.up state = state.up end if value.root? return Either.failure("cannot move to prev before first segment") end state = state.prev value = value.prev until value.node.segment? value = value.down.last state = state.down.last end end # Synchronize the two parallel state and value nodes unless value.eql?(state.node.zipper) state = state.replace(state.node.copy(:zipper => value)) end state end Either.success(StateMachine.new(@config, active)) end |
#segment ⇒ Either<Zipper::AbstractCursor<Values::SegmentVal>>
Extracts the segment from the current state, if the current state is deterministic and positioned on a segment.
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# File 'lib/stupidedi/builder/navigation.rb', line 98 def segment zipper.flatmap do |z| if z.node.segment? Either.success(z) else Either.failure("not a segment") end end end |
#segmentn ⇒ Either<Values::SegmentVal>
Extracts the segment from the current state, if the current state is deterministic and positioned on a segment.
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# File 'lib/stupidedi/builder/navigation.rb', line 112 def segmentn segment.map(&:node) end |
#sequence(pattern, *patterns) ⇒ Either<StateMachine>
Sequence multiple traversals together, by iteratively calling ‘find`. Each argument must be either a single segment ID or a list whose first element is a segment ID and remaining elements are segment constraints.
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# File 'lib/stupidedi/builder/navigation.rb', line 479 def sequence(pattern, *patterns) patterns.inject(find(*pattern)) do |m, p| m = m.flatmap{|n| n.find(*p) } end end |
#successors ⇒ Array<InstructionTable>
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# File 'lib/stupidedi/builder/navigation.rb', line 14 def successors @active.map{|a| a.node.instructions } end |
#zipper ⇒ Either<Zipper::AbstractCursor<Values::AbstractVal>>
Returns the current position within the parse tree, if the current state is deterministic.
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# File 'lib/stupidedi/builder/navigation.rb', line 86 def zipper if deterministic? Either.success(@active.head.node.zipper) else Either.failure("non-deterministic state") end end |