Module: Kapusta::Compiler::EmitterModules::SimpleExpression

Defined in:
lib/kapusta/compiler/emitter/simple_expression.rb

Constant Summary collapse

KEYWORDS = 
%w[nil true false self].freeze
OPENERS = 
{ '(' => ')', '[' => ']', '{' => '}' }.freeze
CLOSERS = 
OPENERS.values.freeze
PRIMARY_OPENERS =

‘…` is intentionally excluded — a top-level hash or block literal shouldn’t be treated as a bare primary even though balanced.

{ '(' => ')', '[' => ']' }.freeze
PRIMARY_PATTERNS = 
[
  /\A-?\d+(?:\.\d+)?/, # number (incl. negative literal)
  /\A:[a-zA-Z_]\w*[!?=]?/, # :symbol
  /\A"(?:[^"\\]|\\.)*"/, # "string"
  /\A'(?:[^'\\]|\\.)*'/, # 'string'
  /\A@@?[a-z_]\w*/, # @ivar / @@cvar
  /\A\$[a-zA-Z_]\w*/, # $gvar
  /\A[A-Z]\w*(?:::[A-Z]\w*)*/, # Constant / A::B::C
  /\A[a-z_]\w*[!?=]?/ # local or bare call head
].freeze
CHAIN_METHOD = 
/\A\.[a-zA-Z_]\w*[!?=]?/

Class Method Summary collapse

Class Method Details

.consume(code, pos) ⇒ Object 



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# File 'lib/kapusta/compiler/emitter/simple_expression.rb', line 46

def consume(code, pos)
  pos = consume_primary(code, pos)
  while pos && pos < code.length
    advanced = consume_segment(code, pos)
    break unless advanced

    pos = advanced
  end
  pos
end

.consume_group(code, pos) ⇒ Object 



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# File 'lib/kapusta/compiler/emitter/simple_expression.rb', line 78

def consume_group(code, pos)
  return unless OPENERS.key?(code[pos])

  stack = [OPENERS[code[pos]]]
  pos += 1
  quote = nil
  while pos < code.length
    ch = code[pos]
    if quote
      if ch == '\\' && pos + 1 < code.length
        pos += 2
      else
        quote = nil if ch == quote
        pos += 1
      end
    elsif ['"', "'"].include?(ch)
      quote = ch
      pos += 1
    elsif OPENERS.key?(ch)
      stack.push(OPENERS[ch])
      pos += 1
    elsif CLOSERS.include?(ch)
      return unless stack.last == ch

      stack.pop
      pos += 1
      return pos if stack.empty?
    else
      pos += 1
    end
  end
  nil
end

.consume_primary(code, pos) ⇒ Object 



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# File 'lib/kapusta/compiler/emitter/simple_expression.rb', line 57

def consume_primary(code, pos)
  return consume_group(code, pos) if PRIMARY_OPENERS.key?(code[pos])

  regex = PRIMARY_PATTERNS.find { |re| code[pos..].match?(re) }
  return unless regex

  after = pos + regex.match(code[pos..]).end(0)
  code[after] == '(' ? consume_group(code, after) : after
end

.consume_segment(code, pos) ⇒ Object 



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# File 'lib/kapusta/compiler/emitter/simple_expression.rb', line 67

def consume_segment(code, pos)
  return consume_group(code, pos) if code[pos] == '['
  return unless code[pos] == '.'

  match = CHAIN_METHOD.match(code[pos..])
  return unless match

  after = pos + match.end(0)
  code[after] == '(' ? consume_group(code, after) : after
end

.match?(code) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/kapusta/compiler/emitter/simple_expression.rb', line 31

def match?(code)
  return false if code.empty? || code.include?("\n")
  return true if KEYWORDS.include?(code)
  return negation?(code) if code.start_with?('!')

  consume(code, 0) == code.length
end

.negation?(code) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/kapusta/compiler/emitter/simple_expression.rb', line 39

def negation?(code)
  return false if code.length < 2

  rest = code[1..]
  match?(rest) || (rest.start_with?('(') && rest.end_with?(')'))
end