Class: Filtri

Inherits:
Object
  • Object
show all
Defined in:
lib/filtri.rb,
lib/filtri/version.rb

Overview

Filtri DSL

Author:

Constant Summary collapse

RULES = 
[:rule, :meta]
VERSION =

Filtri version (semantic versioning)

"0.1.2"

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Filtri

Returns a new instance of Filtri.



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# File 'lib/filtri.rb', line 20

def initialize
  @rules      = []
  @meta_rules = []
  @passes     = 1
  @meta_applied = false
end

Instance Attribute Details

#meta_rules ⇒ Object (readonly)

The meta rules



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# File 'lib/filtri.rb', line 13

def meta_rules
  @meta_rules
end

#rules ⇒ Object (readonly)

The rules



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# File 'lib/filtri.rb', line 11

def rules
  @rules
end

Class Method Details

.from_str(rule_str) ⇒ Filtri

Factory, init with rule-set from a string

The input string is expected to contain rules and comments, one per line, separated by a line break. The expected format of a line is ‘operation <space> argument <eol>’. Empty lines and lines starting with a ‘#’ are ignored. Whitespace at the beginning of a line is trimmed.

Parameters:

  • rule_str (String)

Returns:

  • (Filtri) —

    A new Filtri object with the rules parsed from the provided string(s).

Raises:

  • (FiltriInitError) —

    if an error occurs when initialising the rules from the provided strings



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# File 'lib/filtri.rb', line 158

def self.from_str(rule_str)

  inst = Filtri.new
  inst.add_rule_str rule_str
  inst

end

.load(file_name) ⇒ Filtri

Factory, Init by loading rules from a file

Parameters:

  • file_name (String)

Returns:

  • (Filtri) —

    A new Filtri object with the rules contained in the file

Raises:

  • (IOError, SystemCallError) —

    If an error occurs when opening the file

  • (FiltriInitError) —

    If an error occurs when parsing the rules in the file



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# File 'lib/filtri.rb', line 182

def self.load(file_name)

  data = IO.read(file_name)
  Filtri.from_str(data)

end

.valid_rules ⇒ Object 



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# File 'lib/filtri.rb', line 190

def self.valid_rules
  Filtri::RULES
end

Instance Method Details

#add_rule(rule_set, rule_hash) ⇒ Object

Add a rule to the current rule-set

Parameters:

  • rule_set (Array<Hash{Regexp => String},Hash{String => String}>)
  • rule_hash (Hash{Regexp => String}, Hash{String => String}) 


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# File 'lib/filtri.rb', line 43

def add_rule(rule_set, rule_hash)

  rule_hash.each_key do |k|
    rule_set << { from: k, to: rule_hash[k] }
  end

end

#add_rule_str(rule_str) ⇒ Object

The input string is expected to contain rules and comments, one per line, separated by a line break. The expected format of a line is “operation <space> argument <eol>”. Empty lines and lines starting with a ‘#’ are ignored. Whitespace at the beginning of a line is trimmed.

Parameters:

  • rule_str (String)

Raises:

  • (FiltriInitError) —

    if an error occurs when initialising the rules from the provided strings



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# File 'lib/filtri.rb', line 118

def add_rule_str(rule_str)

  rule_str.strip.lines do |l|

    op_str = l.strip.partition " "
    if op_str[0].length > 0
      op     = op_str[0]
      op_arg = op_str[2]

      if Filtri::RULES.include? op.to_sym
        # parse arg string
        begin
          arg_hash = op_arg.to_h
        rescue Parslet::ParseFailed => err
          raise FiltriInitError, "Invalid rule format: '#{op_arg}' (#{err.message})"
        end
        # add rule
        self.send(op.to_sym,arg_hash)
      else
        raise FiltriInitError, "Unknown rule: #{op}" unless ( op == "#" || l[0] == "#" )
      end

    end
  end


end

#apply(in_str) ⇒ String

Apply filtering rules to the provided string

Parameters:

  • in_str (String)

Returns:

  • (String) —

    the resulting string



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# File 'lib/filtri.rb', line 91

def apply(in_str)

  @passes.times do

    unless @meta_rules.empty?
      unless @meta_applied
        @rules = rewrite(@rules, @meta_rules)
        @meta_applied = true
      end
    end

    @rules.each do |rule|
      in_str = in_str.gsub(rule[:from], rule[:to])
    end

  end
  in_str
end

#do_rewrite(val, rule) ⇒ Object

Parameters:

  • val (Regexp, String)
  • rule (Hash{Regexp => String}, Hash{String => String}) 


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# File 'lib/filtri.rb', line 54

def do_rewrite(val, rule)
  case val
    when Regexp
      val_str = PP.singleline_pp(val, "")
      val_str.gsub!(rule[:from], rule[:to])
      val_str.to_regexp
    when String
      val.gsub(rule[:from], rule[:to])
    else
      val
  end

end

#load(file_name) ⇒ Object

Load rules from a file

Parameters:

  • file_name (String)

Raises:

  • (IOError, SystemCallError) —

    If an error occurs when opening the file

  • (FiltriInitError) —

    If an error occurs when parsing the rules in the file



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# File 'lib/filtri.rb', line 170

def load(file_name)

  data = IO.read(file_name)
  add_rule_str(data)

end

#meta(rule_hash) ⇒ Object

Add a meta rule

Parameters:

  • rule_hash (Hash{Regexp=>String}) 


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# File 'lib/filtri.rb', line 35

def meta(rule_hash)
  add_rule(@meta_rules, rule_hash)
end

#rewrite(in_hash, rules) ⇒ Object

Rewrite a hash with a set of rules

Parameters:

  • in_hash (Hash{Regexp => String}, Hash{String => String})
  • rules (Hash{Regexp => String}, Hash{String => String}) 


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# File 'lib/filtri.rb', line 72

def rewrite(in_hash, rules)
  out_hash = []
  in_hash.each do |v|
    f = v[:from]
    t = v[:to]

    rules.each do |r|
      f = do_rewrite(f, r)
      t = do_rewrite(t, r)
    end
    out_hash << { from: f, to: t }
  end
  out_hash
end

#rule(rule_hash) ⇒ Object

Add a filtering rule

Parameters:

  • rule_hash (Hash{Regexp => String}, Hash{String => String}) 


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# File 'lib/filtri.rb', line 29

def rule(rule_hash)
  add_rule(@rules, rule_hash)
end