Class: Argstring::Lexer::Segmenter

Inherits:
Object
  • Object
show all
Defined in:
lib/argstring/lexer/segmenter.rb

Instance Method Summary collapse

Constructor Details

#initialize(config) ⇒ Segmenter

Returns a new instance of Segmenter.



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# File 'lib/argstring/lexer/segmenter.rb', line 6

def initialize(config)
	@config = config
end

Instance Method Details

#split(argstring, errors:) ⇒ Object

Split argstring into raw segments using the configured separator. Enclosures and escapes prevent splitting.



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# File 'lib/argstring/lexer/segmenter.rb', line 12

def split(argstring, errors:)
	# Always strip leading/trailing whitespace globally in all modes.
	# Users who want leading/trailing whitespace must enclose it.
	argstring = argstring.to_s.strip
	
	segments = []
	buffer = +""

	i = 0
	in_enclosure = false
	current_encloser = nil

	while i < argstring.length
		ch = argstring[i]

		if in_enclosure
			# Escape inside enclosure consumes next character literally.
			if @config.escape_enabled? && ch == @config.escape
				if i + 1 < argstring.length
					buffer << ch
					buffer << argstring[i + 1]
					i += 2
				else
					buffer << ch
					i += 1
				end
				next
			end

			buffer << ch
			if ch == current_encloser[:close]
				in_enclosure = false
				current_encloser = nil
			end
			i += 1
			next
		end

		# Start enclosure if configured.
		pair = @config.encloser_open_pair_for(ch)
		if pair
			in_enclosure = true
			current_encloser = pair
			buffer << ch
			i += 1
			next
		end

		# Escape outside enclosure.
		if @config.escape_enabled? && ch == @config.escape
			# If separator is whitespace, escaping whitespace separators is not allowed.
			if @config.whitespace_separator? && i + 1 < argstring.length && @config.whitespace_char?(argstring[i + 1])
				i += 1
				next
			end

			if i + 1 < argstring.length
				buffer << ch
				buffer << argstring[i + 1]
				i += 2
			else
				buffer << ch
				i += 1
			end
			next
		end

		# Separator handling.
		if @config.separator_boundary_at?(argstring, i)
			flush_segment!(segments, buffer)

			if @config.whitespace_separator?
				# Collapse whitespace runs.
				while i < argstring.length && @config.whitespace_char?(argstring[i])
					i += 1
				end
			else
				# Non-whitespace separator does not collapse.
				i += 1
			end
			next
		end

		buffer << ch
		i += 1
	end

	if in_enclosure
		errors << ParseError.new(
			code: :unterminated_enclosure,
			message: "Unterminated enclosure in input"
		)
		return []
	end

	flush_segment!(segments, buffer)
	segments
end