Class: LXL::Parser

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

Constant Summary collapse

RUBY_OPERATORS = 
['+', '-', '*', '/', '<=', '>=', '==', '!=', '<', '>']
EXCEL_OPERATORS = 
['+', '-', '*', '/', '<=', '>=', '=',  '<>', '<', '>']

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Parser

Initialize parser



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# File 'lib/lxl.rb', line 89

def initialize

  # Constants
  @constants = {
    :TRUE  => true,
    :FALSE => false,
    :NULL  => nil,
  }
  
  # Functions
  @functions = Hash.new
  register(:AND)   { |a,b| to_b(a) && to_b(b) }
  register(:OR)    { |a,b| to_b(a) || to_b(b) }
  register(:IF)    { |v,a,b| to_b(v) ? a : b }
  register(:LIST)  { |*args| args }
  register(:IN)    { |n,h| h.respond_to?(:include?) ? h.include?(n) : false }
  register(:TODAY) { Date.today.ajd.to_f }
  register(:NOW)   { DateTime.now.ajd.to_f }
  register(:DATE)  { |y,m,d| Date.new(y,m,d).ajd.to_f }
  register(:TIME)  { |h,m,s|
    DateTime.valid_time?(h,m,s) ? DateTime.valid_time?(h,m,s).to_f : raise(ArgumentError, 'invalid time')
  }
  register(:DATETIME) { |value| DateTime.parse(value).ajd.to_f }

  # Lexer
  ops = EXCEL_OPERATORS.collect { |v| Regexp.quote(v) }.join('|')
  #
  @lexer = LXL::LittleLexer.new([
                      [/\A[\s,]+/,?w] ,        # Whitespace (includes Commas)
                      [/\A;+/, ?;],            # Semi-Colon (statement separator)
                      [/\A(#{ops})/,?o],       # Operator
                      [/\A[0-9]+\.[0-9]+/,?f], # Float
                      [/\A[0-9]+/,?i],         # Integer
                      [/\A("[^\"]*")/m,?s],    # String (single quoted)
                      [/\A('[^\']*')/m,?S],    # String (double quoted)
                      [/\A\w+/,?t],            # Token
                      [/\A\(/,?(],             # Open (
                      [/\A\)/,?)],             # Close )
                    ], false)

  # Other
  @tokens = Array.new
  @types = Array.new
end

Instance Attribute Details

#constants ⇒ Object (readonly)

Returns the value of attribute constants.



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# File 'lib/lxl.rb', line 76

def constants
  @constants
end

#functions ⇒ Object (readonly)

Returns the value of attribute functions.



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# File 'lib/lxl.rb', line 76

def functions
  @functions
end

#lexer ⇒ Object (readonly)

Returns the value of attribute lexer.



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# File 'lib/lxl.rb', line 76

def lexer
  @lexer
end

#tokens ⇒ Object (readonly)

Returns the value of attribute tokens.



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# File 'lib/lxl.rb', line 76

def tokens
  @tokens
end

#types ⇒ Object (readonly)

Returns the value of attribute types.



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# File 'lib/lxl.rb', line 76

def types
  @types
end

Class Method Details

.eval(formula) ⇒ Object

Evaluate a formula



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# File 'lib/lxl.rb', line 83

def self.eval(formula)
  self.new.eval(formula)
end

Instance Method Details

#eval(formula) ⇒ Object

Evaluate formula



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# File 'lib/lxl.rb', line 136

def eval(formula)
  tokenize(formula.to_s.strip)
  @tokens.pop if @tokens.last == ';'
  if @tokens.include?(';')
    expr = [ [] ]
    @tokens.each do |token|
      if token == ';'
        expr << []
      else
        expr.last << token
      end
    end
    expr.collect { |e| Kernel.eval(e.join, binding) }
  else
    Kernel.eval(@tokens.join, binding)
  end
end