Class: Rich::JavaScriptLexer

Inherits:
BaseLexer show all
Defined in:
lib/rich/syntax.rb

Overview

JavaScript lexer

Constant Summary collapse

KEYWORDS = 
%w[
  async await break case catch class const continue debugger default
  delete do else export extends finally for function if import in
  instanceof let new return static super switch this throw try typeof
  var void while with yield true false null undefined
].freeze
BUILTINS = 
%w[
  Array Boolean Date Error Function JSON Math Number Object Promise
  RegExp String Symbol Map Set WeakMap WeakSet Proxy Reflect
  console window document parseInt parseFloat isNaN isFinite
  decodeURI decodeURIComponent encodeURI encodeURIComponent eval
  setTimeout setInterval clearTimeout clearInterval fetch
].freeze

Instance Method Summary collapse

Instance Method Details

#tokenize(line, theme) ⇒ Object 



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# File 'lib/rich/syntax.rb', line 683

def tokenize(line, theme)
  segments = []
  pos = 0

  while pos < line.length
    if line[pos].match?(/\s/)
      ws_end = pos
      ws_end += 1 while ws_end < line.length && line[ws_end].match?(/\s/)
      segments << Segment.new(line[pos...ws_end])
      pos = ws_end
      next
    end

    # Single-line comment
    if line[pos..pos + 1] == "//"
      segments << Segment.new(line[pos..], style: theme[:comment])
      break
    end

    # Template literal
    if line[pos] == "`"
      str_end = find_string_end(line, pos, "`")
      segments << Segment.new(line[pos..str_end], style: theme[:string])
      pos = str_end + 1
      next
    end

    # String
    if ['"', "'"].include?(line[pos])
      delim = line[pos]
      str_end = find_string_end(line, pos, delim)
      segments << Segment.new(line[pos..str_end], style: theme[:string])
      pos = str_end + 1
      next
    end

    # Regex
    if line[pos] == "/" && (pos == 0 || line[pos - 1].match?(/[\s=({,\[]/)) &&
       pos + 1 < line.length && line[pos + 1] != " "
      regex_end = find_closing_delimiter(line, pos, "/")
      if regex_end
        # Include flags
        regex_end += 1 while regex_end + 1 < line.length && line[regex_end + 1].match?(/[gimsuy]/)
        segments << Segment.new(line[pos..regex_end], style: theme[:string_regex] || theme[:string])
        pos = regex_end + 1
        next
      end
    end

    # Number
    if line[pos].match?(/\d/) || (line[pos] == "." && pos + 1 < line.length && line[pos + 1].match?(/\d/))
      num_end = pos
      num_end += 1 while num_end < line.length && line[num_end].match?(/[\d._xXoObBeEnN]/)
      segments << Segment.new(line[pos...num_end], style: theme[:number])
      pos = num_end
      next
    end

    # Identifier
    if line[pos].match?(/[a-zA-Z_$]/)
      word_end = pos
      word_end += 1 while word_end < line.length && line[word_end].match?(/[\w$]/)
      word = line[pos...word_end]

      style = if KEYWORDS.include?(word)
                theme[:keyword]
              elsif BUILTINS.include?(word)
                theme[:name_builtin] || theme[:name]
              elsif word[0].match?(/[A-Z]/)
                theme[:name_class] || theme[:name]
              else
                theme[:name]
              end

      segments << Segment.new(word, style: style)
      pos = word_end
      next
    end

    # Arrow function
    if line[pos..pos + 1] == "=>"
      segments << Segment.new("=>", style: theme[:operator])
      pos += 2
      next
    end

    # Operators
    if line[pos].match?(/[+\-*\/%&|^~<>=!?:]/)
      op_end = pos + 1
      op_end += 1 while op_end < line.length && line[op_end].match?(/[+\-*\/%&|^~<>=!?:]/)
      segments << Segment.new(line[pos...op_end], style: theme[:operator])
      pos = op_end
      next
    end

    # Punctuation
    if line[pos].match?(/[(){}\[\].,;]/)
      segments << Segment.new(line[pos], style: theme[:punctuation])
      pos += 1
      next
    end

    segments << Segment.new(line[pos])
    pos += 1
  end

  segments
end