Module: Feen::Parser::StyleTurn

Defined in:
lib/feen/parser/style_turn.rb

Overview

Handles parsing of the style turn section of a FEEN string

Constant Summary collapse

ERRORS =

Error messages for style turn parsing

{
  invalid_type:   "Style turn must be a string, got %s",
  empty_string:   "Style turn string cannot be empty",
  invalid_format: "Invalid style turn format. Expected format: UPPERCASE/lowercase or lowercase/UPPERCASE",
  invalid_snn:    "Invalid SNN notation in style turn: %s"
}.freeze
VALID_STYLE_TURN_PATTERN =

Pattern matching the FEEN specification for style turn <style-turn> ::= <style-id-uppercase> “/” <style-id-lowercase>

| <style-id-lowercase> "/" <style-id-uppercase>

%r{
  \A                                    # Start of string
  (?:                                   # Non-capturing group for alternatives
    (?<uppercase_first>[A-Z][A-Z0-9]*) # Named group: uppercase style identifier first
    /                                   # Separator
    (?<lowercase_second>[a-z][a-z0-9]*) # Named group: lowercase style identifier second
    |                                   # OR
    (?<lowercase_first>[a-z][a-z0-9]*) # Named group: lowercase style identifier first
    /                                   # Separator
    (?<uppercase_second>[A-Z][A-Z0-9]*) # Named group: uppercase style identifier second
  )
  \z                                    # End of string
}x

Class Method Summary collapse

Class Method Details

.parse(style_turn_str) ⇒ Array<String>

Parses the style turn section of a FEEN string

Examples:

Valid style turn string with uppercase first

StyleTurn.parse("CHESS/shogi")
# => ["CHESS", "shogi"]

Valid style turn string with lowercase first

StyleTurn.parse("chess/SHOGI")
# => ["chess", "SHOGI"]

Valid style turn with numeric identifiers

StyleTurn.parse("CHESS960/makruk")
# => ["CHESS960", "makruk"]

Parameters:

  • style_turn_str (String) —

    FEEN style turn string

Returns:

  • (Array<String>) —

    Array containing [active_style, inactive_style]

Raises:

  • (ArgumentError) —

    If the input string is invalid



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# File 'lib/feen/parser/style_turn.rb', line 51

def self.parse(style_turn_str)
  validate_input_type(style_turn_str)

  match = VALID_STYLE_TURN_PATTERN.match(style_turn_str)
  raise ::ArgumentError, ERRORS[:invalid_format] unless match

  style_identifiers = extract_style_identifiers(match)
  validate_snn_compliance(style_identifiers)

  style_identifiers
end