Class: Dentaku::Parser

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

Constant Summary collapse

AST_OPERATIONS = 
{
  add:      AST::Addition,
  subtract: AST::Subtraction,
  multiply: AST::Multiplication,
  divide:   AST::Division,
  pow:      AST::Exponentiation,
  negate:   AST::Negation,
  mod:      AST::Modulo,

  bitor:    AST::BitwiseOr,
  bitand:   AST::BitwiseAnd,
  bitshiftleft:  AST::BitwiseShiftLeft,
  bitshiftright: AST::BitwiseShiftRight,

  lt:       AST::LessThan,
  gt:       AST::GreaterThan,
  le:       AST::LessThanOrEqual,
  ge:       AST::GreaterThanOrEqual,
  ne:       AST::NotEqual,
  eq:       AST::Equal,

  and:      AST::And,
  or:       AST::Or,
  xor:      AST::Xor,
}.freeze

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(tokens, options = {}) ⇒ Parser

Returns a new instance of Parser.



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# File 'lib/dentaku/parser.rb', line 33

def initialize(tokens, options = {})
  @input             = tokens.dup
  @output            = []
  @operations        = options.fetch(:operations, [])
  @arities           = options.fetch(:arities, [])
  @function_registry = options.fetch(:function_registry, nil)
  @case_sensitive    = options.fetch(:case_sensitive, false)
  @skip_indices      = []
end

Instance Attribute Details

#arities ⇒ Object (readonly)

Returns the value of attribute arities.



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

def arities
  @arities
end

#case_sensitive ⇒ Object (readonly)

Returns the value of attribute case_sensitive.



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

def case_sensitive
  @case_sensitive
end

#input ⇒ Object (readonly)

Returns the value of attribute input.



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

def input
  @input
end

#operations ⇒ Object (readonly)

Returns the value of attribute operations.



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

def operations
  @operations
end

#output ⇒ Object (readonly)

Returns the value of attribute output.



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

def output
  @output
end

Instance Method Details

#consume(count = 2) ⇒ Object 



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# File 'lib/dentaku/parser.rb', line 43

def consume(count = 2)
  operator = operations.pop
  fail! :invalid_statement if operator.nil?

  output_size = output.length
  args_size = operator.arity || count
  min_size = operator.arity || operator.min_param_count || count
  max_size = operator.arity || operator.max_param_count || count

  if output_size < min_size || args_size < min_size
    expect = min_size == max_size ? min_size : min_size..max_size
    fail! :too_few_operands, operator: operator, expect: expect, actual: output_size
  end

  if (output_size > max_size && operations.empty?) || args_size > max_size
    expect = min_size == max_size ? min_size : min_size..max_size
    fail! :too_many_operands, operator: operator, expect: expect, actual: output_size
  end

  args = []
  if operator == AST::Array && output.empty?
    # special case: empty array literal '{}'
    output.push(operator.new)
  else
    fail! :invalid_statement if output_size < args_size
    args = Array.new(args_size) { output.pop }.reverse
    output.push operator.new(*args)
  end

  if operator.respond_to?(:callback) && !operator.callback.nil?
    operator.callback.call(args)
  end
rescue ::ArgumentError => e
  raise Dentaku::ArgumentError, e.message
rescue NodeError => e
  fail! :node_invalid, operator: operator, child: e.child, expect: e.expect, actual: e.actual
end

#function(token) ⇒ Object 



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# File 'lib/dentaku/parser.rb', line 107

def function(token)
  function_registry.get(token.value)
end

#function_registry ⇒ Object 



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# File 'lib/dentaku/parser.rb', line 111

def function_registry
  @function_registry ||= Dentaku::AST::FunctionRegistry.new
end

#operation(token) ⇒ Object 



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# File 'lib/dentaku/parser.rb', line 103

def operation(token)
  AST_OPERATIONS.fetch(token.value)
end

#parse ⇒ Object 



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# File 'lib/dentaku/parser.rb', line 81

def parse
  return AST::Nil.new if input.empty?

  i = 0
  while i < input.length
    if @skip_indices.include?(i)
      i += 1
      next
    end
    token = input[i]
    lookahead = input[i + 1]
    process_token(token, lookahead, i, input)
    i += 1
  end

  consume while operations.any?

  fail! :invalid_statement unless output.count == 1

  output.first
end