Class: Lisp::Parser

Inherits:
Object show all
Defined in:
lib/rubylisp/parser.rb

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Parser

Returns a new instance of Parser.



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# File 'lib/rubylisp/parser.rb', line 5

def initialize
end

Instance Method Details

#make_character(ch) ⇒ Object 



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# File 'lib/rubylisp/parser.rb', line 28

def make_character(ch)
  Lisp::Character.with_value(ch)
end

#make_float(str) ⇒ Object 



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# File 'lib/rubylisp/parser.rb', line 16

def make_float(str)
  Lisp::Number.with_value(str.to_f)
end

#make_hex_number(str) ⇒ Object 



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# File 'lib/rubylisp/parser.rb', line 12

def make_hex_number(str)
  Lisp::Number.with_value(["0x", str].join.to_i(0))
end

#make_number(str) ⇒ Object 



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# File 'lib/rubylisp/parser.rb', line 8

def make_number(str)
  Lisp::Number.with_value(str.to_i)
end

#make_string(str) ⇒ Object 



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# File 'lib/rubylisp/parser.rb', line 20

def make_string(str)
  Lisp::String.with_value(str)
end

#make_symbol(str) ⇒ Object 



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# File 'lib/rubylisp/parser.rb', line 24

def make_symbol(str)
  Lisp::Symbol.named(str)
end

#parse(src) ⇒ Object 



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# File 'lib/rubylisp/parser.rb', line 186

def parse(src)
  tokenizer = Tokenizer.from_string(src)
  self.parse_sexpr(tokenizer)
end

#parse_and_eval(src, env = Lisp::EnvironmentFrame.global) ⇒ Object 



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# File 'lib/rubylisp/parser.rb', line 197

def parse_and_eval(src, env=Lisp::EnvironmentFrame.global)
  sexpr = self.parse(src)
  return sexpr.evaluate(env)
end

#parse_and_eval_all(src, env = Lisp::EnvironmentFrame.global) ⇒ Object 



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# File 'lib/rubylisp/parser.rb', line 202

def parse_and_eval_all(src, env=Lisp::EnvironmentFrame.global)
  tokenizer = Tokenizer.from_string(src)
  result = nil
  until tokenizer.eof?
    sexpr = self.parse_sexpr(tokenizer)
    result = sexpr.evaluate(env)
  end
  result
end

#parse_cons_cell(tokens) ⇒ Object 



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# File 'lib/rubylisp/parser.rb', line 32

def parse_cons_cell(tokens)
  tok, lit = tokens.next_token
  if tok == :RPAREN
    tokens.consume_token
    return Lisp::ConsCell.cons()
  end

  car = nil
  cdr = nil
  cells = []
  while tok != :RPAREN
    if tok == :PERIOD
      tokens.consume_token
      cdr = self.parse_sexpr(tokens)
      return nil if tokens.next_token[0] == :EOF
      tok, lit = tokens.next_token
      return Lisp::Debug.process_error("Expected ')' to follow a dotted tail on line #{tokens.line_number}", Lisp::EnvironmentFrame.global) if tok != :RPAREN
      tokens.consume_token
      return Lisp::ConsCell.array_to_list(cells, cdr)
    else
      car = self.parse_sexpr(tokens)
      return Lisp::Debug.process_error("Unexpected EOF (expected ')') on line #{tokens.line_number}", Lisp::EnvironmentFrame.global) if tokens.next_token[0] == :EOF
      cells << car
    end
    tok, lit = tokens.next_token
  end

  tokens.consume_token
  Lisp::ConsCell.array_to_list(cells)
end

#parse_frame(tokens, literal) ⇒ Object 



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# File 'lib/rubylisp/parser.rb', line 63

def parse_frame(tokens, literal)
  m = {}
  tok, lit = tokens.next_token
  if tok == :RBRACE
    tokens.consume_token
    if literal
      Lisp::Frame.new
    else
      Lisp::ConsCell.cons(Lisp::Symbol.named("make-frame"), nil)
    end
  else
    cells = []
    while tok != :RBRACE
      item = self.parse_sexpr(tokens)
      return Lisp::Debug.process_error("Unexpected EOF (expected '}') on line #{tokens.line_number}", env) if tokens.next_token[0] == :EOF
      cells << item
      tok, lit = tokens.next_token
    end
    
    tokens.consume_token
    keys_and_values = Lisp::ConsCell.array_to_list(cells)
    if literal
      Lisp::PrimFrame.make_frame_impl(keys_and_values, Lisp::EnvironmentFrame.global)
    else
      Lisp::ConsCell.cons(Lisp::Symbol.named("make-frame"), keys_and_values)
    end
  end
end

#parse_object_from_file(port, env = Lisp::EnvironmentFrame.global) ⇒ Object 



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# File 'lib/rubylisp/parser.rb', line 191

def parse_object_from_file(port, env=Lisp::EnvironmentFrame.global)
  tokenizer = Tokenizer.from_file(port)
  result = self.parse_sexpr(tokenizer)
  result.nil? ? Lisp::EofObject.instance : result
end

#parse_sexpr(tokens) ⇒ Object 



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# File 'lib/rubylisp/parser.rb', line 123

def parse_sexpr(tokens)
  while true
    tok, lit = tokens.next_token
    # puts "token: <#{tok}, #{lit}>"
    return nil if tok == :EOF
    tokens.consume_token
    case tok
    when :COMMENT
      next
    when :NUMBER
      return make_number(lit)
    when :FLOAT
      return make_float(lit)
    when :HEXNUMBER
      return make_hex_number(lit)
    when :STRING
      return make_string(lit)
    when :CHARACTER
      return make_character(lit)
    when :LPAREN
      return parse_cons_cell(tokens)
    when :LBRACE
      return parse_frame(tokens, false)
    when :QUOTE_LBRACE
      return parse_frame(tokens, true)
    when :HASH_LPAREN
      return parse_vector(tokens, false)
    when :QUOTE_HASH_LPAREN
      return parse_vector(tokens, true)
    when :SYMBOL
      return make_symbol(lit)
    when :FFI_NEW_SYMBOL
      return Lisp::FfiNew.new(lit)
    when :FFI_SEND_SYMBOL
      return Lisp::FfiSend.new(lit)
    when :FFI_STATIC_SYMBOL
      return Lisp::FfiStatic.new(lit)
    when :FALSE
      return Lisp::FALSE
    when :TRUE
      return Lisp::TRUE
    when :QUOTE
      expr = parse_sexpr(tokens)
      return Lisp::ConsCell.array_to_list([Lisp::Symbol.named('quote'), expr])
    when :BACKQUOTE
      expr = parse_sexpr(tokens)
      return Lisp::ConsCell.array_to_list([Lisp::Symbol.named('quasiquote'), expr])
    when :COMMA
      expr = parse_sexpr(tokens)
      return Lisp::ConsCell.array_to_list([Lisp::Symbol.named('unquote'), expr])
    when :COMMAAT
      expr = parse_sexpr(tokens)
      return Lisp::ConsCell.array_to_list([Lisp::Symbol.named('unquote-splicing'), expr])
    when :WHITESPACE
      next
    when :ILLEGAL
      return Lisp::Debug.process_error("Illegal token: #{lit} on line #{tokens.line_number}", Lisp::EnvironmentFrame.global)
    else
      return make_symbol(lit)
    end
  end
end

#parse_vector(tokens, literal) ⇒ Object 



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# File 'lib/rubylisp/parser.rb', line 93

def parse_vector(tokens, literal)
  v = []
  tok, lit = tokens.next_token
  if tok == :RPAREN
    tokens.consume_token
    if literal
      Lisp::Vector.new
    else
      Lisp::ConsCell.cons(Lis::Symbol.named("vector"), nil)
    end
  else
    cells = []
    while tok != :RPAREN
      item = self.parse_sexpr(tokens)
      return Lisp::Debug.process_error("Unexpected EOF (expected ')') on line #{tokens.line_number}", env) if tokens.next_token[0] == :EOF
      cells << item
      tok, lit = tokens.next_token
    end
    
    tokens.consume_token
    
    if literal
      Lisp::Vector.with_array(cells)
    else
      Lisp::ConsCell.cons(Lisp::Symbol.named("vector"), Lisp::ConsCell.array_to_list(cells))
    end
  end
end

#process_file(fname) ⇒ Object 



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# File 'lib/rubylisp/parser.rb', line 212

def process_file(fname)
  File.open(fname) do |f|
    parse_and_eval_all(f.read)
  end
end