Module: Patriot::Util::Param

Included in:
Command::Base
Defined in:
lib/patriot/util/param.rb

Overview

namespace for parameter handling functions

Instance Method Summary collapse

Instance Method Details

#eval_attr(attr_val) ⇒ Object

replace parameter values in command attribute valeus

Parameters:

  • attr_val —

    an attribute value to be evaluated



8
9
10
11
12
13
14
15
16
17
18
19
20
21
 
# File 'lib/patriot/util/param.rb', line 8

def eval_attr(attr_val)
  if attr_val.is_a?(Hash)
    entries = {}
    attr_val.each{|k,v| entries[eval_attr(k)] = eval_attr(v) }
    return entries
  elsif attr_val.is_a?(Array)
    return attr_val.map{|e| eval_attr(e)}
  elsif attr_val.is_a?(String)
    return eval_string_attr(attr_val)
  else
    # only evaluate attributes in String
    return attr_val
  end
end

#eval_string_attr(str, vars = {}) ⇒ String

evaluate variables in a string expression

Parameters:

  • str (String) —

    a string expression to be evaluated

  • vars (Hash) (defaults to: {}) —

    variables used in the evaluation

Returns:

  • (String) —

    a evaluated string expression



27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
 
# File 'lib/patriot/util/param.rb', line 27

def eval_string_attr(str, vars = {})
  s = StringScanner.new(str)
  s.scan(/(.*?)\#\{/m)
  # retrun immediatelly if variables are not contained
  return str unless s.matched?
  prefix = s[1]
  nest = 1 # depth of parenthesis
  var = "" # variable expression
  prev_rest = s.rest
  while nest > 0
    tmp = s.scan(/(.*?)[\{\}]/m) # for hash objects, etc
    if s.matched?
      if /.*?\{/ =~ tmp
        nest = nest + 1
        var << s[0]
      else 
        nest = nest - 1
        if nest >  0
          var << s[0]
        else
          # does not include the last parenthesis indicates end of the variable 
          var << s[1]
        end
      end
    end
    raise "infinte loop #{str} : rest #{s.rest} : #{nest}" if prev_rest == s.rest
    prev_rest = s.rest
  end
  # evaluate the variable
  var_binding = build_var_binding(vars)
  var_binding = binding if var_binding.nil?
  evaled_var = eval var, var_binding
  # farther variables are handled by next invocation
  return "#{prefix}#{evaled_var}#{eval_string_attr(prev_rest, vars)}"
end