Module: Kerbi::Mixins::EntryTagLogic

Extended by:
ActiveSupport::Concern
Included in:
State::EntrySet
Defined in:
lib/mixins/entry_tag_logic.rb

Overview

Mixin for handling mission critical state entry tag logic. The logic is most comprised name resolution, i.e turning special words that users pass in place of literal tags, into literal tags.

Defined Under Namespace

Modules: ClassMethods

Constant Summary collapse

SPECIAL_CHAR = 
"@"
CANDIDATE_WORD = 
"candidate"
NEW_CANDIDATE_WORD = 
"new-candidate"
LATEST_WORD = 
"latest"
LATEST_PLUS_WORD = 
"latest+\\."
OLDEST_WORD = 
"oldest"
RANDOM_WORD = 
"random"
SPECIAL_READ_WORDS = 
[
  CANDIDATE_WORD,
  LATEST_PLUS_WORD,
  LATEST_WORD,
  OLDEST_WORD
]
SPECIAL_WRITE_WORDS = 
[
  LATEST_PLUS_WORD,
  LATEST_WORD,
  OLDEST_WORD,
  CANDIDATE_WORD,
  NEW_CANDIDATE_WORD,
  RANDOM_WORD
]

Instance Method Summary collapse

Instance Method Details

#do_resolve_tag_expr(tag_expr, verb) ⇒ String

Main logic to template state entry tag expressions (that users use to identify state entries with) into a final, usable tag.

The method finds special words in the tag expression, which start with the SPECIAL_CHAR ‘@’, and substitutes them one at a time with a computed value. For instance, @latest will become the actual tag of the latest state entry, and @random will become a random string.

Depending on whether the user’s request is for reading or writing an entry, different substitutions are available.

Parameters:

  • tag_expr (String)
  • verb (String)

Returns:

  • (String) 


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# File 'lib/mixins/entry_tag_logic.rb', line 73

def do_resolve_tag_expr(tag_expr, verb)
  raise "Internal error" unless %w[read write].include?(verb)
  words = verb == 'read' ? SPECIAL_READ_WORDS : SPECIAL_WRITE_WORDS

  resolved_tag = tag_expr
  words.each do |special_word|
    part = "#{SPECIAL_CHAR}#{special_word}"
    if tag_expr.include?(part)
      resolved_word = resolve_word(special_word, verb)
      resolved_tag = resolved_tag.gsub(part, resolved_word)
    end
  end
  resolved_tag
end

#resolve_candidate_read_word ⇒ String

Single word resolver. Looks for the latest candidate state entry and returns its tag or an empty string if there is no latest candidate state.

Returns:

  • (String) 


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# File 'lib/mixins/entry_tag_logic.rb', line 121

def resolve_candidate_read_word
  latest_candidate&.tag || ""
end

#resolve_candidate_write_word ⇒ String

Single word resolver. Outputs a non-taken random tag (given by #generate_random_tag) prefixed with candidate flag prefix [cand]-.

Returns:

  • (String) 


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# File 'lib/mixins/entry_tag_logic.rb', line 129

def resolve_candidate_write_word
  resolve_candidate_read_word || resolve_new_candidate_word
end

#resolve_latest_word ⇒ String

Single word resolver. Looks for the latest committed state entry and returns its tag or an empty string if there is no latest committed state.

Returns:

  • (String) 


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# File 'lib/mixins/entry_tag_logic.rb', line 146

def resolve_latest_word
  latest&.tag || ""
end

#resolve_new_candidate_word ⇒ Object 



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# File 'lib/mixins/entry_tag_logic.rb', line 133

def resolve_new_candidate_word
  prefix = Kerbi::State::Entry::CANDIDATE_PREFIX
  begin
    tag = "#{prefix}#{self.class.generate_random_tag}"
  end while candidates.find{ |e| e.tag == tag }
  tag
end

#resolve_oldest_word ⇒ String

Single word resolver. Looks for the latest committed state entry and returns its tag or an empty string if there is no latest committed state.

Returns:

  • (String) 


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# File 'lib/mixins/entry_tag_logic.rb', line 155

def resolve_oldest_word
  oldest&.tag || ""
end

#resolve_random_word ⇒ String

Single word resolver. Outputs a non-taken random tag (given by #generate_random_tag).

Returns:

  • (String) 


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# File 'lib/mixins/entry_tag_logic.rb', line 163

def resolve_random_word
  begin
    tag = self.class.generate_random_tag
  end while entries.find{ |e|e.tag == tag }
  tag
end

#resolve_read_tag_expr(tag_expr) ⇒ String

Calls #do_resolve_tag_expr with verb=read in order to turn an entry tag expression like @latest into 2.1.1

See documentation for #resolve_word for information on how resolution works at the word level.

Parameters:

  • tag_expr (String)

Returns:

  • (String) 


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# File 'lib/mixins/entry_tag_logic.rb', line 56

def resolve_read_tag_expr(tag_expr)
  do_resolve_tag_expr(tag_expr, "read")
end

#resolve_word(word, verb) ⇒ Object

Performs a special word substitution for an individual special word, like ‘latest’, ‘random’, or ‘candidate’. Works by looking for a corresponding the word-resolver method in self.

E.g if you pass ‘random’, it expects the method resolve_random_word to exist.

Because the same special word can have different interpretations depending on whether the mode (read or write), this method will first look for the mode-specialized version of the word-resolver function, e.g if passed ‘candidate’ in ‘read’ mode, it will first look out for the a word-resolver method called ‘resolve_candidate_read_word’ and call it instead of the less specialized ‘resolve_candidate_word’ method.

Parameters:

  • word (String) —

    a special word (‘latest’, ‘random’, ‘candidate’)

  • verb (Object) —

    whether this is a read or write operation



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# File 'lib/mixins/entry_tag_logic.rb', line 105

def resolve_word(word, verb)
  word = word.gsub("-", "_")
  if respond_to?((method = "resolve_#{word}_#{verb}_word"))
    send(method)
  elsif respond_to?((method = "resolve_#{word}_word"))
    send(method)
  else
    raise "What is #{word}??"
  end
end

#resolve_write_tag_expr(tag_expr) ⇒ String

Calls #do_resolve_tag_expr with verb=write in order to turn an entry tag expression like @candidate-new into [cand]purple-forest-new.

See documentation for #resolve_word for information on how resolution works at the word level.

Parameters:

  • tag_expr (String)

Returns:

  • (String) 


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# File 'lib/mixins/entry_tag_logic.rb', line 44

def resolve_write_tag_expr(tag_expr)
  do_resolve_tag_expr(tag_expr, "write")
end