class Filtri

Filtri DSL @author karl l <karl@ninjacontrol.com>

Constants

RULES: @private
VERSION: Filtri version (semantic versioning)

Attributes

meta_rules[R]

The meta rules

rules[R]

The rules

Public Class Methods

from_str(rule_str) click to toggle source

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.

@param [String] rule_str @return [Filtri] A new Filtri object with the rules parsed from the provided string(s). @raise [FiltriInitError] if an error occurs when initialising the rules from the provided strings

# 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) click to toggle source

Factory, Init by loading rules from a file @param [String] file_name @return [Filtri] A new Filtri object with the rules contained in the file @raise [IOError,SystemCallError] If an error occurs when opening the file @raise [FiltriInitError] If an error occurs when parsing the rules in the file

# File lib/filtri.rb, line 182
def self.load(file_name)

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

end

new() click to toggle source

# File lib/filtri.rb, line 20
def initialize
  @rules      = []
  @meta_rules = []
  @passes     = 1
  @meta_applied = false
end

valid_rules() click to toggle source

# File lib/filtri.rb, line 190
def self.valid_rules
  Filtri::RULES
end

Public Instance Methods

add_rule(rule_set, rule_hash) click to toggle source

Add a rule to the current rule-set @param [Array<Hash{Regexp => String},Hash{String => String}>] rule_set @param [Hash{Regexp => String},Hash{String => String}] rule_hash @private

# 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) click to toggle source

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.

@param [String] rule_str @raise [FiltriInitError] if an error occurs when initialising the rules from the provided strings

# 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) click to toggle source

Apply filtering rules to the provided string @param [String] in_str @return [String] the resulting string

# 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) click to toggle source

@param [Regexp, String] val @param [Hash{Regexp => String},Hash{String => String}] rule @private

# 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) click to toggle source

Load rules from a file @param [String] file_name @raise [IOError,SystemCallError] If an error occurs when opening the file @raise [FiltriInitError] If an error occurs when parsing the rules in the file

# File lib/filtri.rb, line 170
def load(file_name)

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

end

meta(rule_hash) click to toggle source

Add a meta rule @param [Hash{Regexp=>String}] rule_hash

# File lib/filtri.rb, line 35
def meta(rule_hash)
  add_rule(@meta_rules, rule_hash)
end

rewrite(in_hash, rules) click to toggle source

Rewrite a hash with a set of rules @param [Hash{Regexp => String},Hash{String => String}] in_hash @param [Hash{Regexp => String},Hash{String => String}] rules @private

# 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) click to toggle source

Add a filtering rule @param [Hash{Regexp => String},Hash{String => String}] rule_hash

# File lib/filtri.rb, line 29
def rule(rule_hash)
  add_rule(@rules, rule_hash)
end