Class: Fop::Parser

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

Defined Under Namespace

Classes: Error

Constant Summary collapse

DIGIT = 
/^[0-9]$/
REGEX_START = 
"^".freeze
REGEX_LAZY_WILDCARD = 
".*?".freeze
REGEX_MATCHES = 
{
  "N" => "[0-9]+".freeze,
  "W" => "\\w+".freeze,
  "A" => "[a-zA-Z]+".freeze,
  "*" => ".*".freeze,
}.freeze
OPS_WITH_OPTIONAL_ARGS = 
[Tokenizer::OP_REPLACE]
TR_REGEX = 
/.*/

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(src, debug: false) ⇒ Parser

Returns a new instance of Parser.



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# File 'lib/fop/parser.rb', line 26

def initialize(src, debug: false)
  @tokenizer = Tokenizer.new(src)
  @errors = []
end

Instance Attribute Details

#errors ⇒ Object (readonly)

Returns the value of attribute errors.



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

def errors
  @errors
end

Instance Method Details

#build_regex!(wildcard, token, src = token.val) ⇒ Object 



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# File 'lib/fop/parser.rb', line 155

def build_regex!(wildcard, token, src = token.val)
  Regexp.new((wildcard ? REGEX_LAZY_WILDCARD : REGEX_START) + src)
rescue RegexpError => e
  errors << Error.new(:regex, token, e.message)
  nil
end

#parse ⇒ Object 



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# File 'lib/fop/parser.rb', line 31

def parse
  nodes = []
  wildcard = false
  eof = false
  # Top-level parsing. It will always be looking for a String, Regex, or Expression.
  until eof
    @tokenizer.reset_escapes!
    t = @tokenizer.next
    case t.type
    when Tokens::WILDCARD
      errors << Error.new(:syntax, t, "Consecutive wildcards") if wildcard
      wildcard = true
    when Tokens::TEXT
      reg = build_regex!(wildcard, t, Regexp.escape(t.val))
      nodes << Nodes::Text.new(wildcard, t.val, reg)
      wildcard = false
    when Tokens::EXP_OPEN
      nodes << parse_exp!(wildcard)
      wildcard = false
    when Tokens::REG_DELIM
      nodes << parse_regex!(wildcard)
      wildcard = false
    when Tokens::EOF
      eof = true
    else
      errors << Error.new(:syntax, t, "Unexpected #{t.type}")
    end
  end
  nodes << Nodes::Text.new(true, "", TR_REGEX) if wildcard
  return nodes, @errors
end

#parse_exp!(wildcard = false) ⇒ Object 



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

def parse_exp!(wildcard = false)
  exp = Nodes::Expression.new(wildcard)
  parse_exp_match! exp
  op_token = parse_exp_operator! exp
  if exp.operator
    parse_exp_arg! exp, op_token
  end
  return exp
end

#parse_exp_arg!(exp, op_token) ⇒ Object 



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# File 'lib/fop/parser.rb', line 109

def parse_exp_arg!(exp, op_token)
  @tokenizer.escape.operators = true
  @tokenizer.escape.regex = true
  @tokenizer.escape.regex_capture = false if exp.regex_match

  exp.arg = []
  found_close, eof = false, false
  until found_close or eof
    t = @tokenizer.next
    case t.type
    when Tokens::TEXT
      exp.arg << t.val
    when Tokens::REG_CAPTURE
      exp.arg << t.val.to_i - 1
      errors << Error.new(:syntax, t, "Invalid regex capture; must be between 0 and 9 (found #{t.val})") unless t.val =~ DIGIT
      errors << Error.new(:syntax, t, "Unexpected regex capture; expected str or '}'") if !exp.regex_match
    when Tokens::EXP_CLOSE
      found_close = true
    when Tokens::EOF
      eof = true
      errors << Error.new(:syntax, t, "Unexpected #{t.type}; expected str or '}'")
    else
      errors << Error.new(:syntax, t, "Unexpected #{t.type}; expected str or '}'")
    end
  end

  if exp.arg.size != 1 and !OPS_WITH_OPTIONAL_ARGS.include?(exp.operator)
    errors << Error.new(:arg, op_token, "Operator '#{op_token.val}' requires an argument")
  end
end

#parse_exp_match!(exp) ⇒ Object 



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# File 'lib/fop/parser.rb', line 73

def parse_exp_match!(exp)
  @tokenizer.escape.operators = false
  t = @tokenizer.next
  case t.type
  when Tokens::TEXT, Tokens::WILDCARD
    exp.match = t.val
    if (src = REGEX_MATCHES[exp.match])
      reg = Regexp.new((exp.wildcard ? REGEX_LAZY_WILDCARD : REGEX_START) + src)
      exp.regex = Nodes::Regex.new(exp.wildcard, src, reg)
    else
      errors << Error.new(:name, t, "Unknown match type '#{exp.match}'") if exp.regex.nil?
    end
  when Tokens::REG_DELIM
    exp.regex = parse_regex!(exp.wildcard)
    exp.match = exp.regex&.src
    exp.regex_match = true
    @tokenizer.reset_escapes!
  else
    errors << Error.new(:syntax, t, "Unexpected #{t.type}; expected a string or a regex")
  end
end

#parse_exp_operator!(exp) ⇒ Object 



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# File 'lib/fop/parser.rb', line 95

def parse_exp_operator!(exp)
  @tokenizer.escape.operators = false
  t = @tokenizer.next
  case t.type
  when Tokens::EXP_CLOSE
    # no op
  when Tokens::OPERATOR
    exp.operator = t.val
  else
    errors << Error.new(:syntax, t, "Unexpected #{t.type}; expected an operator")
  end
  t
end

#parse_regex!(wildcard) ⇒ Object 



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# File 'lib/fop/parser.rb', line 140

def parse_regex!(wildcard)
  @tokenizer.regex_mode!
  t = @tokenizer.next
  reg = Nodes::Regex.new(wildcard, t.val)
  if t.type == Tokens::TEXT
    reg.regex = build_regex!(wildcard, t)
  else
    errors << Error.new(:syntax, t, "Unexpected #{t.type}; expected a string of regex")
  end

  t = @tokenizer.next
  errors << Error.new(:syntax, t, "Unexpected #{t.type}; expected a string of regex") unless t.type == Tokens::REG_DELIM
  reg
end