├── .travis.yml
├── spec
    ├── spec_helper.cr
    └── jager_spec.cr
├── .editorconfig
├── .gitignore
├── shard.yml
├── src
    ├── jager
    │   ├── regex.bnf
    │   └── helpers.cr
    └── jager.cr
├── README.md
└── LICENSE


/.travis.yml:
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1 | language: crystal
2 | 


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/spec/spec_helper.cr:
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1 | require "spec"
2 | require "../src/jager"
3 | 


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/.editorconfig:
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1 | [*.cr]
2 | charset = utf-8
3 | end_of_line = lf
4 | insert_final_newline = true
5 | indent_style = space
6 | indent_size = 2
7 | trim_trailing_whitespace = true
8 | 


--------------------------------------------------------------------------------
/.gitignore:
--------------------------------------------------------------------------------
1 | /docs/
2 | /lib/
3 | /bin/
4 | /.shards/
5 | 
6 | # Libraries don't need dependency lock
7 | # Dependencies will be locked in application that uses them
8 | /shard.lock
9 | 


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/shard.yml:
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 1 | name: jager
 2 | version: 0.5.0
 3 | 
 4 | authors:
 5 |   - Omar Roth <omarroth@protonmail.com>
 6 | 
 7 | description: |
 8 |   Reverse regular expression engine
 9 | 
10 | crystal: 0.34.0
11 | 
12 | dependencies:
13 |   marpa:
14 |     github: omarroth/marpa
15 |     branch: master
16 | 
17 | license: GPLv3
18 | 


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/src/jager/regex.bnf:
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 1 | :start ::= regex
 2 | regex ::= union
 3 | | elements
 4 | 
 5 | union ::= elements+ separator => <union op> action => union proper => 1
 6 | <union op> ~ '|'
 7 | 
 8 | elements ::= element+
 9 | element ::= '(' regex ')' action => capture_group
10 | | '(?=' regex ')' action => not_implemented
11 | | '(?!' regex ')' action => not_implemented
12 | | '(?:' regex ')' action => not_implemented
13 | | '(?' flags '-' flags ':' regex ')' action => subpattern
14 | | '[' <character set elements> ']' action => character_set
15 | | '[^' <character set elements> ']' action => negated_set
16 | | element '+' action => plus
17 | | element '*' action => star
18 | | element '?' action => optional
19 | | element quantifier action => quantifier
20 | | character action => character
21 | | group action => group
22 | 
23 | quantifier ::= '{' min '}'
24 | | '{' min ',' '}'
25 | | '{' min ',' max '}'
26 | 
27 | min ~ number
28 | max ~ number
29 | 
30 | flags ~ [imsx]*
31 | number ~ [\d]+
32 | 
33 | <character set elements> ::= <character set element>*
34 | <character set element> ::= range action => range
35 | | group action => group
36 | | character
37 | | <set character>
38 | 
39 | range ::= character '-' character
40 | group ~ /\\[wWdDsS]|\./
41 | 
42 | character ::= ascii
43 | | <reserved character> action => reserved_character
44 | | <escaped character> action => escaped_character
45 | | <octal escape> action => octal_escape
46 | | <hexadecimal escape> action => hexadecimal_escape
47 | | <unicode escape> action => unicode_escape
48 | | <extended unicode escape> action => extended_unicode_escape
49 | | <control character escape> action => control_character_escape
50 | 
51 | ascii ~ [ !"#%&',0-9:;<=>@A-Z_`a-z{}~-]
52 | <reserved character> ~ /\\[+*?^$\\\.\[\]\{\}\(\)\|\/]/
53 | <escaped character> ~ '\' ascii
54 | <set character> ~ [+*?^$.[{}()|/]
55 | 
56 | <octal escape> ~ /\\[\d]{3}/
57 | <hexadecimal escape> ~ /\\x[a-fA-F0-9]{2}/
58 | <unicode escape> ~ /\\u[a-fA-F0-9]{4}/
59 | <extended unicode escape> ~ /(\\u|\\x){[a-zA-Z0-9]+}/
60 | <control character escape> ~ /\\c[a-zA-Z]/


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/spec/jager_spec.cr:
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 1 | require "./spec_helper"
 2 | 
 3 | describe Jager do
 4 |   describe "#generate" do
 5 |     # Make sure engine generates matching string
 6 |     it "US Phone" do
 7 |       regex = /\d{3}-\d{3}-\d{4}/
 8 |       engine = Jager::Engine.new
 9 | 
10 |       input = engine.generate(regex)
11 | 
12 |       if md = input.match(regex)
13 |         match = md[0]
14 |       end
15 | 
16 |       match.should eq input
17 |     end
18 | 
19 |     it "UUID" do
20 |       regex = /[a-f0-9]{8}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{12}/
21 |       engine = Jager::Engine.new
22 | 
23 |       input = engine.generate(regex)
24 | 
25 |       if md = input.match(regex)
26 |         match = md[0]
27 |       end
28 | 
29 |       match.should eq input
30 |     end
31 | 
32 |     it "JSON Number" do
33 |       regex = /-?[1-9]\d+(\.\d+)?([eE][+-]?\d+)?/
34 |       engine = Jager::Engine.new
35 | 
36 |       input = engine.generate(regex)
37 | 
38 |       if md = input.match(regex)
39 |         match = md[0]
40 |       end
41 | 
42 |       match.should eq input
43 |     end
44 | 
45 |     it "US Dollar amount" do
46 |       regex = /\$([1-9]{1}[0-9]{0,2})(,\d{3}){0,4}(\.\d{2})?/
47 |       engine = Jager::Engine.new
48 | 
49 |       input = engine.generate(regex)
50 | 
51 |       if md = input.match(regex)
52 |         match = md[0]
53 |       end
54 | 
55 |       match.should eq input
56 |     end
57 | 
58 |     it "JSON String" do
59 |       regex = /"([^"\\]|\\[\"\\\/bftnrt]|\\u[a-fA-F0-9]{4})*"/
60 |       engine = Jager::Engine.new
61 | 
62 |       input = engine.generate(regex).inspect
63 | 
64 |       if md = input.match(regex)
65 |         match = md[0]
66 |       end
67 | 
68 |       match.should eq input
69 |     end
70 | 
71 |     it "tests escaped characters" do
72 |       regex = /([\x30-\x4d\x{142}-\x{332}\cI\x{40ae}\x{40ea}])+/
73 |       engine = Jager::Engine.new
74 | 
75 |       input = engine.generate(regex)
76 | 
77 |       if md = input.match(regex)
78 |         match = md[0]
79 |       end
80 | 
81 |       match.should eq input
82 |     end
83 |   end
84 | end
85 | 


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/README.md:
--------------------------------------------------------------------------------
 1 | # jager
 2 | 
 3 | I would recommend re-implementing this if you plan on using it for anything yourself. The approach in this library is a poorly-informed implementation based on parser actions.
 4 | 
 5 | If anyone is curious on how something like this would be implemented **correctly** I would recommend reading Russ Cox's series of posts, and convert a regular expression into a proper DFA as described [here](https://swtch.com/~rsc/regexp/regexp1.html). Then this library reduces to traversing the DFA randomly until reaching an accept state.
 6 | 
 7 | [![GitHub release](https://img.shields.io/github/release/omarroth/jager.svg)](https://github.com/omarroth/jager/releases)
 8 | 
 9 | > This is a project built with [marpa](https://github.com/omarroth/marpa).
10 | 
11 | Given a regular expression, generate a string that matches that expression
12 | 
13 | ## Installation
14 | 
15 | Add this to your application's `shard.yml`:
16 | 
17 | ```yaml
18 | dependencies:
19 |   jager:
20 |     github: omarroth/jager
21 | ```
22 | 
23 | ## Usage
24 | 
25 | ```crystal
26 | require "jager"
27 | 
28 | regex = /\d{3}-\d{3}-\d{4}/
29 | engine = Jager::Engine.new
30 | 
31 | input = engine.generate(regex)
32 | 
33 | input # => "754-327-6740"
34 | ```
35 | 
36 | ## Examples
37 | 
38 | | Name        | Regex                                                          | Output                                 |
39 | | ----------- | -------------------------------------------------------------- | -------------------------------------- |
40 | | US Phone    | /\d{3}-\d{3}-\d{4}/                                            | "019-586-1821"                         |
41 | | UUID        | /[a-f0-9]{8}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{12}/ | "0d007d29-f50b-4763-f40e-102fcaa77a1b" |
42 | | JSON Number | /-?[1-9]\d+(.\d+)?([eE][+-]?\d+)?/                             | "85.2292e+6745508109"                  |
43 | | US Dollar   | /\\$([1-9]{1}[0-9]{0,2})(,\d{3}){0,4}(.\d{2})?/                | "$7,239,557,686.39"                    |
44 | 
45 | ## Notes
46 | 
47 | - Jager does **not** support:
48 |   - anchors (`$`, `^`),
49 |   - extended character classes (`[[:digit:]]`, `[[:alpha:]]`)
50 | 
51 | ## Contributing
52 | 
53 | 1.  Fork it ( https://github.com/omarroth/jager/fork )
54 | 2.  Create your feature branch (git checkout -b my-new-feature)
55 | 3.  Commit your changes (git commit -am 'Add some feature')
56 | 4.  Push to the branch (git push origin my-new-feature)
57 | 5.  Create a new Pull Request
58 | 
59 | ## Contributors
60 | 
61 | - [omarroth](https://github.com/omarroth) Omar Roth - creator, maintainer
62 | 


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/src/jager/helpers.cr:
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 1 | module Jager
 2 |   class Engine
 3 |     def build_regex_grammar(actions)
 4 |       actions.create_symbol([["regex"]])
 5 |       actions.start_rule([":start", "::=", [[["regex"]]]])
 6 |       actions.create_symbol([["union"]])
 7 |       actions.create_symbol([["elements"]])
 8 |       actions.priority_rule([[[["regex"]]], ["::="], [[[[[[[["union"]]]]], [] of String], "|", [[[[[["elements"]]]]], [] of String]]]])
 9 |       actions.create_symbol([["<union op>"]])
10 |       actions.quantified_rule([[[["union"]]], ["::="], [[["elements"]]], ["+"], [[["separator", "=>", [[["<union op>"]]]]], [["action", "=>", "union"]], [["proper", "=>", "1"]]]])
11 |       actions.create_literal(["'|'"])
12 |       actions.priority_rule([[[["<union op>"]]], ["~"], [[[[[["'|'"]]], [] of String]]]])
13 |       actions.create_symbol([["element"]])
14 |       actions.quantified_rule([[[["elements"]]], ["::="], [[["element"]]], ["+"], [] of String])
15 |       actions.create_literal(["'('"])
16 |       actions.create_literal(["')'"])
17 |       actions.create_literal(["'(?='"])
18 |       actions.create_literal(["'(?!'"])
19 |       actions.create_literal(["'(?:'"])
20 |       actions.create_literal(["'(?'"])
21 |       actions.create_symbol([["flags"]])
22 |       actions.create_literal(["'-'"])
23 |       actions.create_literal(["':'"])
24 |       actions.create_literal(["'['"])
25 |       actions.create_symbol([["<character set elements>"]])
26 |       actions.create_literal(["']'"])
27 |       actions.create_literal(["'[^'"])
28 |       actions.create_literal(["'+'"])
29 |       actions.create_literal(["'*'"])
30 |       actions.create_literal(["'?'"])
31 |       actions.create_symbol([["quantifier"]])
32 |       actions.create_symbol([["character"]])
33 |       actions.create_symbol([["group"]])
34 |       actions.priority_rule([[[["element"]]], ["::="], [[[[[["'('"]], [[[["regex"]]]], [["')'"]]], [[["action", "=>", "capture_group"]]]], "|", [[[["'(?='"]], [[[["regex"]]]], [["')'"]]], [[["action", "=>", "not_implemented"]]]], "|", [[[["'(?!'"]], [[[["regex"]]]], [["')'"]]], [[["action", "=>", "not_implemented"]]]], "|", [[[["'(?:'"]], [[[["regex"]]]], [["')'"]]], [[["action", "=>", "not_implemented"]]]], "|", [[[["'(?'"]], [[[["flags"]]]], [["'-'"]], [[[["flags"]]]], [["':'"]], [[[["regex"]]]], [["')'"]]], [[["action", "=>", "subpattern"]]]], "|", [[[["'['"]], [[[["<character set elements>"]]]], [["']'"]]], [[["action", "=>", "character_set"]]]], "|", [[[["'[^'"]], [[[["<character set elements>"]]]], [["']'"]]], [[["action", "=>", "negated_set"]]]], "|", [[[[[["element"]]]], [["'+'"]]], [[["action", "=>", "plus"]]]], "|", [[[[[["element"]]]], [["'*'"]]], [[["action", "=>", "star"]]]], "|", [[[[[["element"]]]], [["'?'"]]], [[["action", "=>", "optional"]]]], "|", [[[[[["element"]]]], [[[["quantifier"]]]]], [[["action", "=>", "quantifier"]]]], "|", [[[[[["character"]]]]], [[["action", "=>", "character"]]]], "|", [[[[[["group"]]]]], [[["action", "=>", "group"]]]]]]])
35 |       actions.create_literal(["'{'"])
36 |       actions.create_symbol([["min"]])
37 |       actions.create_literal(["'}'"])
38 |       actions.create_literal(["','"])
39 |       actions.create_symbol([["max"]])
40 |       actions.priority_rule([[[["quantifier"]]], ["::="], [[[[[["'{'"]], [[[["min"]]]], [["'}'"]]], [] of String], "|", [[[["'{'"]], [[[["min"]]]], [["','"]], [["'}'"]]], [] of String], "|", [[[["'{'"]], [[[["min"]]]], [["','"]], [[[["max"]]]], [["'}'"]]], [] of String]]]])
41 |       actions.create_symbol([["number"]])
42 |       actions.priority_rule([[[["min"]]], ["~"], [[[[[[[["number"]]]]], [] of String]]]])
43 |       actions.priority_rule([[[["max"]]], ["~"], [[[[[[[["number"]]]]], [] of String]]]])
44 |       actions.create_character_class(["[imsx]"])
45 |       actions.quantified_rule([[[["flags"]]], ["~"], ["[imsx]"], ["*"], [] of String])
46 |       actions.create_character_class(["[\\d]"])
47 |       actions.quantified_rule([[[["number"]]], ["~"], ["[\\d]"], ["+"], [] of String])
48 |       actions.create_symbol([["<character set element>"]])
49 |       actions.quantified_rule([[[["<character set elements>"]]], ["::="], [[["<character set element>"]]], ["*"], [] of String])
50 |       actions.create_symbol([["range"]])
51 |       actions.create_symbol([["<set character>"]])
52 |       actions.priority_rule([[[["<character set element>"]]], ["::="], [[[[[[[["range"]]]]], [[["action", "=>", "range"]]]], "|", [[[[[["group"]]]]], [[["action", "=>", "group"]]]], "|", [[[[[["character"]]]]], [] of String], "|", [[[[[["<set character>"]]]]], [] of String]]]])
53 |       actions.priority_rule([[[["range"]]], ["::="], [[[[[[[["character"]]]], [["'-'"]], [[[["character"]]]]], [] of String]]]])
54 |       actions.create_regex(["/\\\\[wWdDsS]|\\./"])
55 |       actions.priority_rule([[[["group"]]], ["~"], [[[[["\\\\[wWdDsS]|\\."]], [] of String]]]])
56 |       actions.create_symbol([["ascii"]])
57 |       actions.create_symbol([["<reserved character>"]])
58 |       actions.create_symbol([["<escaped character>"]])
59 |       actions.create_symbol([["<octal escape>"]])
60 |       actions.create_symbol([["<hexadecimal escape>"]])
61 |       actions.create_symbol([["<unicode escape>"]])
62 |       actions.create_symbol([["<extended unicode escape>"]])
63 |       actions.create_symbol([["<control character escape>"]])
64 |       actions.priority_rule([[[["character"]]], ["::="], [[[[[[[["ascii"]]]]], [] of String], "|", [[[[[["<reserved character>"]]]]], [[["action", "=>", "reserved_character"]]]], "|", [[[[[["<escaped character>"]]]]], [[["action", "=>", "escaped_character"]]]], "|", [[[[[["<octal escape>"]]]]], [[["action", "=>", "octal_escape"]]]], "|", [[[[[["<hexadecimal escape>"]]]]], [[["action", "=>", "hexadecimal_escape"]]]], "|", [[[[[["<unicode escape>"]]]]], [[["action", "=>", "unicode_escape"]]]], "|", [[[[[["<extended unicode escape>"]]]]], [[["action", "=>", "extended_unicode_escape"]]]], "|", [[[[[["<control character escape>"]]]]], [[["action", "=>", "control_character_escape"]]]]]]])
65 |       actions.create_character_class(["[ !\"#%&',0-9:;<=>@A-Z_`a-z{}~-]"])
66 |       actions.priority_rule([[[["ascii"]]], ["~"], [[[[[["[ !\"#%&',0-9:;<=>@A-Z_`a-z{}~-]"]]], [] of String]]]])
67 |       actions.create_regex(["/\\\\[+*?^$\\\\\\.\\[\\]\\{\\}\\(\\)\\|\\/]/"])
68 |       actions.priority_rule([[[["<reserved character>"]]], ["~"], [[[[["\\\\[+*?^$\\\\\\.\\[\\]\\{\\}\\(\\)\\|\\/]"]], [] of String]]]])
69 |       actions.create_literal(["'\\'"])
70 |       actions.priority_rule([[[["<escaped character>"]]], ["~"], [[[[[["'\\'"]], [[[["ascii"]]]]], [] of String]]]])
71 |       actions.create_character_class(["[+*?^$.[{}()|/]"])
72 |       actions.priority_rule([[[["<set character>"]]], ["~"], [[[[[["[+*?^$.[{}()|/]"]]], [] of String]]]])
73 |       actions.create_regex(["/\\\\[\\d]{3}/"])
74 |       actions.priority_rule([[[["<octal escape>"]]], ["~"], [[[[["\\\\[\\d]{3}"]], [] of String]]]])
75 |       actions.create_regex(["/\\\\x[a-fA-F0-9]{2}/"])
76 |       actions.priority_rule([[[["<hexadecimal escape>"]]], ["~"], [[[[["\\\\x[a-fA-F0-9]{2}"]], [] of String]]]])
77 |       actions.create_regex(["/\\\\u[a-fA-F0-9]{4}/"])
78 |       actions.priority_rule([[[["<unicode escape>"]]], ["~"], [[[[["\\\\u[a-fA-F0-9]{4}"]], [] of String]]]])
79 |       actions.create_regex(["/(\\\\u|\\\\x){[a-zA-Z0-9]+}/"])
80 |       actions.priority_rule([[[["<extended unicode escape>"]]], ["~"], [[[[["(\\\\u|\\\\x){[a-zA-Z0-9]+}"]], [] of String]]]])
81 |       actions.create_regex(["/\\\\c[a-zA-Z]/"])
82 |       actions.priority_rule([[[["<control character escape>"]]], ["~"], [[[[["\\\\c[a-zA-Z]"]], [] of String]]]])
83 | 
84 |       return actions
85 |     end
86 |   end
87 | end
88 | 


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/src/jager.cr:
--------------------------------------------------------------------------------
  1 | # Reverse regular expression engine
  2 | # Copyright (C) 2019  Omar Roth
  3 | #
  4 | # This program is free software: you can redistribute it and/or modify
  5 | # it under the terms of the GNU General Public License as published by
  6 | # the Free Software Foundation, either version 3 of the License, or
  7 | # (at your option) any later version.
  8 | #
  9 | # This program is distributed in the hope that it will be useful,
 10 | # but WITHOUT ANY WARRANTY; without even the implied warranty of
 11 | # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 12 | # GNU General Public License for more details.
 13 | #
 14 | # You should have received a copy of the GNU General Public License
 15 | # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 16 | 
 17 | require "./jager/*"
 18 | require "marpa"
 19 | 
 20 | module Jager
 21 |   alias Node = {value: String, edges: Array(Int32)}
 22 | 
 23 |   class Actions < Marpa::Actions
 24 |     ACCEPTABLE_CHARS = (' '..'~').to_a
 25 |     DIGIT            = ('0'..'9').to_a
 26 |     NOT_DIGIT        = ACCEPTABLE_CHARS - DIGIT
 27 | 
 28 |     WORD     = ('A'..'Z').to_a + ('a'..'z').to_a + DIGIT + ['_']
 29 |     NOT_WORD = ACCEPTABLE_CHARS - WORD
 30 | 
 31 |     WHITESPACE     = ['\t', '\n', ' ']
 32 |     NOT_WHITESPACE = ACCEPTABLE_CHARS - WHITESPACE
 33 | 
 34 |     property graph
 35 | 
 36 |     def initialize
 37 |       @graph = [] of Node
 38 |     end
 39 | 
 40 |     def capture_group(context)
 41 |       context = context[1].as(Array)
 42 |       context
 43 |     end
 44 | 
 45 |     def subpattern(context)
 46 |       context = context[5].as(Array)
 47 |       context
 48 |     end
 49 | 
 50 |     def group(context)
 51 |       group = context[0].as(String)
 52 | 
 53 |       case group
 54 |       when "\\w"
 55 |         body = WORD
 56 |       when "\\W"
 57 |         body = NOT_WORD
 58 |       when "\\d"
 59 |         body = DIGIT
 60 |       when "\\D"
 61 |         body = NOT_DIGIT
 62 |       when "\\s"
 63 |         body = WHITESPACE
 64 |       when "\\S"
 65 |         body = NOT_WHITESPACE
 66 |       when "."
 67 |         body = ACCEPTABLE_CHARS
 68 |       else
 69 |         raise "Invalid group #{group}"
 70 |       end
 71 | 
 72 |       context.clear
 73 | 
 74 |       @graph << {value: "", edges: (1..body.size).to_a}
 75 |       context << ""
 76 | 
 77 |       body.each_with_index do |element, i|
 78 |         @graph << {value: element.to_s, edges: [body.size - i]}
 79 |         context << ""
 80 |       end
 81 | 
 82 |       context
 83 |     end
 84 | 
 85 |     def character(context)
 86 |       character = context.as(Array)
 87 |       character = context.flatten
 88 |       character = character[0]
 89 | 
 90 |       @graph << {value: character, edges: [1]}
 91 |       context
 92 |     end
 93 | 
 94 |     def union(context)
 95 |       elements = context.as(Array)
 96 |       elements.delete("|")
 97 | 
 98 |       body = @graph.pop(elements.flatten.size)
 99 | 
100 |       edge = 1
101 |       edges = [] of Int32
102 |       elements = elements.map do |element|
103 |         element = element.as(Array)
104 |         element = element.flatten
105 |         element << ""
106 | 
107 |         edges << edge
108 |         edge += element.size
109 | 
110 |         element
111 |       end
112 | 
113 |       edges.each_with_index do |edge, i|
114 |         body.insert(edge + elements[i].size - 2, {value: "", edges: [elements[i..-1].flatten.size - elements[i].size + 1]})
115 |       end
116 | 
117 |       body.insert(0, {value: "", edges: edges})
118 |       @graph += body
119 | 
120 |       context.clear
121 |       body.size.times do
122 |         context << ""
123 |       end
124 |       context
125 |     end
126 | 
127 |     def character_set(context)
128 |       body = context[1].as(Array)
129 |       body = body.flatten
130 | 
131 |       @graph << {value: "", edges: (1..body.size).to_a}
132 |       body.each_with_index do |element, i|
133 |         @graph << {value: element, edges: [body.size - i]}
134 |       end
135 | 
136 |       context.clear
137 | 
138 |       body.size.times do
139 |         context << ""
140 |       end
141 |       context << ""
142 |       context
143 |     end
144 | 
145 |     def negated_set(context)
146 |       body = context[1].as(Array)
147 |       body = body.flatten
148 | 
149 |       body = ACCEPTABLE_CHARS - body
150 | 
151 |       @graph << {value: "", edges: (1..body.size).to_a}
152 |       body.each_with_index do |element, i|
153 |         @graph << {value: element.to_s, edges: [body.size - i]}
154 |       end
155 | 
156 |       context.clear
157 | 
158 |       body.size.times do
159 |         context << ""
160 |       end
161 |       context << ""
162 |       context
163 |     end
164 | 
165 |     def range(context)
166 |       range = context[0].as(Array)
167 | 
168 |       first = range[0].as(Array)
169 |       first = first[0].as(String)
170 |       first = first.chars[0]
171 | 
172 |       last = range[2].as(Array)
173 |       last = last[0].as(String)
174 |       last = last.chars[0]
175 | 
176 |       if first > last
177 |         raise "Range values reversed, #{first} and #{last}."
178 |       end
179 | 
180 |       range = (first..last).to_a
181 | 
182 |       context.clear
183 |       range.each do |char|
184 |         context << char.to_s
185 |       end
186 | 
187 |       context
188 |     end
189 | 
190 |     def escaped_character(context)
191 |       character = context[0].as(String)
192 | 
193 |       case character
194 |       when "\\t"
195 |         context = "\t"
196 |       when "\\n"
197 |         context = "\n"
198 |       when "\\v"
199 |         context = "\v"
200 |       when "\\f"
201 |         context = "\f"
202 |       when "\\r"
203 |         context = "\r"
204 |       when "\\0"
205 |         context = "\0"
206 |       else
207 |         context = character.lchop("\\")
208 |       end
209 | 
210 |       context
211 |     end
212 | 
213 |     def reserved_character(context)
214 |       character = context[0].as(String)
215 |       character = character.lchop("\\")
216 | 
217 |       context[0] = character
218 |       context
219 |     end
220 | 
221 |     def octal_escape(context)
222 |       character = context[0].as(String)
223 |       character = character.lchop("\\").to_u8(base = 8).unsafe_chr.to_s
224 | 
225 |       context[0] = character
226 |       context
227 |     end
228 | 
229 |     def hexadecimal_escape(context)
230 |       character = context[0].as(String)
231 |       character = character.lchop("\\x").to_u8(base = 16).unsafe_chr.to_s
232 | 
233 |       context[0] = character
234 |       context
235 |     end
236 | 
237 |     def unicode_escape(context)
238 |       character = context[0].as(String)
239 |       character = character.lchop("\\u").to_u16(base = 16).unsafe_chr.to_s
240 | 
241 |       context[0] = character
242 |       context
243 |     end
244 | 
245 |     def extended_unicode_escape(context)
246 |       character = context[0].as(String)
247 |       character = character.lchop("\\u").lchop("\\x")
248 |       character = character.lchop("{")
249 |       character = character.rchop("}")
250 |       character = character.to_u32(base = 16).unsafe_chr.to_s
251 | 
252 |       context[0] = character
253 |       context
254 |     end
255 | 
256 |     def control_character_escape(context)
257 |       character = context[0].as(String)
258 | 
259 |       codes = ('A'..'Z').to_a
260 | 
261 |       character = character.lchop("\\c")
262 |       codes.each_with_index do |match, i|
263 |         if character == match.to_s
264 |           character = (i + 1).unsafe_chr.to_s
265 |           break
266 |         end
267 |       end
268 | 
269 |       context[0] = character
270 |       context
271 |     end
272 | 
273 |     def plus(context)
274 |       body = context[0].as(Array)
275 |       body = body.flatten
276 | 
277 |       @graph << {value: "", edges: [1, -body.size]}
278 | 
279 |       context.clear
280 |       body.size.times do
281 |         context << ""
282 |       end
283 |       context << ""
284 |       context
285 |     end
286 | 
287 |     def star(context)
288 |       body = context[0].as(Array)
289 |       body = body.flatten
290 | 
291 |       @graph.insert(-1 - body.size, {value: "", edges: [1, body.size + 2]})
292 |       @graph << {value: "", edges: [-1 - body.size]}
293 | 
294 |       context.clear
295 |       body.size.times do
296 |         context << ""
297 |       end
298 |       context << ""
299 |       context << ""
300 |       context
301 |     end
302 | 
303 |     def quantifier(context)
304 |       body = context[0].as(Array)
305 |       body = body.flatten
306 | 
307 |       quantifier = context[1].as(Array)
308 |       quantifier = quantifier.flatten
309 | 
310 |       min = quantifier[1].to_i
311 |       comma = quantifier[2]?.try &.== ","
312 |       max = quantifier[3]?.try &.to_i?
313 | 
314 |       context.clear
315 |       body = @graph.pop(body.size)
316 | 
317 |       min.times do
318 |         @graph += body
319 |         body.size.times do
320 |           context << ""
321 |         end
322 |       end
323 | 
324 |       if max
325 |         (max - min).times do
326 |           @graph << {value: "", edges: [1, body.size + 1]}
327 |           @graph += body
328 | 
329 |           body.size.times do
330 |             context << ""
331 |           end
332 |           context << ""
333 |         end
334 |       elsif comma
335 |         @graph << {value: "", edges: [1, body.size + 2]}
336 |         @graph += body
337 |         @graph << {value: "", edges: [-1 - body.size]}
338 | 
339 |         body.size.times do
340 |           context << ""
341 |         end
342 |         context << ""
343 |         context << ""
344 |       end
345 | 
346 |       context
347 |     end
348 | 
349 |     def optional(context)
350 |       body = context[0].as(Array)
351 |       body = body.flatten
352 | 
353 |       @graph.insert(-1 - body.size, {value: "", edges: [1, body.size + 1]})
354 | 
355 |       context.clear
356 |       body.size.times do
357 |         context << ""
358 |       end
359 |       context << ""
360 |       context
361 |     end
362 | 
363 |     def not_implemented(context)
364 |       raise "Not implemented: #{context[0]}"
365 |     end
366 |   end
367 | 
368 |   class Engine
369 |     # Generate a string that matches the given regex
370 |     def generate(regex : Regex)
371 |       regex = regex.source
372 | 
373 |       return generate(regex)
374 |     end
375 | 
376 |     # Generate a string that matches the given regular expression (as string)
377 |     def generate(regex : String)
378 |       graph = compile(regex)
379 |       output = generate(graph)
380 | 
381 |       return output
382 |     end
383 | 
384 |     # Given graph, create output until an endpoint is found
385 |     def generate(graph : Array(Node))
386 |       output = ""
387 |       offset = 0
388 | 
389 |       until graph[offset][:edges].empty?
390 |         output += graph[offset][:value]
391 |         offset += graph[offset][:edges].sample(1)[0]
392 |       end
393 | 
394 |       return output
395 |     end
396 | 
397 |     # Compile given regular expression
398 |     def compile(regex : Regex)
399 |       regex = regex.to_s
400 |       regex = regex.partition(":")[2]
401 |       regex = regex.rchop
402 | 
403 |       return compile(regex)
404 |     end
405 | 
406 |     # Compile given regular expression (as string)
407 |     def compile(regex : String)
408 |       parser = Marpa::Parser.new
409 | 
410 |       grammar = Marpa::Builder.new
411 |       grammar = build_regex_grammar(grammar)
412 | 
413 |       actions = Jager::Actions.new
414 |       string = parser.parse(regex, grammar, actions)
415 | 
416 |       graph = actions.graph
417 |       graph << {value: "", edges: [] of Int32}
418 | 
419 |       return graph
420 |     end
421 |   end
422 | end
423 | 


--------------------------------------------------------------------------------
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--------------------------------------------------------------------------------
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  2 |                        Version 3, 29 June 2007
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418 | finally terminates your license, and (b) permanently, if the copyright
419 | holder fails to notify you of the violation by some reasonable means
420 | prior to 60 days after the cessation.
421 | 
422 |   Moreover, your license from a particular copyright holder is
423 | reinstated permanently if the copyright holder notifies you of the
424 | violation by some reasonable means, this is the first time you have
425 | received notice of violation of this License (for any work) from that
426 | copyright holder, and you cure the violation prior to 30 days after
427 | your receipt of the notice.
428 | 
429 |   Termination of your rights under this section does not terminate the
430 | licenses of parties who have received copies or rights from you under
431 | this License.  If your rights have been terminated and not permanently
432 | reinstated, you do not qualify to receive new licenses for the same
433 | material under section 10.
434 | 
435 |   9. Acceptance Not Required for Having Copies.
436 | 
437 |   You are not required to accept this License in order to receive or
438 | run a copy of the Program.  Ancillary propagation of a covered work
439 | occurring solely as a consequence of using peer-to-peer transmission
440 | to receive a copy likewise does not require acceptance.  However,
441 | nothing other than this License grants you permission to propagate or
442 | modify any covered work.  These actions infringe copyright if you do
443 | not accept this License.  Therefore, by modifying or propagating a
444 | covered work, you indicate your acceptance of this License to do so.
445 | 
446 |   10. Automatic Licensing of Downstream Recipients.
447 | 
448 |   Each time you convey a covered work, the recipient automatically
449 | receives a license from the original licensors, to run, modify and
450 | propagate that work, subject to this License.  You are not responsible
451 | for enforcing compliance by third parties with this License.
452 | 
453 |   An "entity transaction" is a transaction transferring control of an
454 | organization, or substantially all assets of one, or subdividing an
455 | organization, or merging organizations.  If propagation of a covered
456 | work results from an entity transaction, each party to that
457 | transaction who receives a copy of the work also receives whatever
458 | licenses to the work the party's predecessor in interest had or could
459 | give under the previous paragraph, plus a right to possession of the
460 | Corresponding Source of the work from the predecessor in interest, if
461 | the predecessor has it or can get it with reasonable efforts.
462 | 
463 |   You may not impose any further restrictions on the exercise of the
464 | rights granted or affirmed under this License.  For example, you may
465 | not impose a license fee, royalty, or other charge for exercise of
466 | rights granted under this License, and you may not initiate litigation
467 | (including a cross-claim or counterclaim in a lawsuit) alleging that
468 | any patent claim is infringed by making, using, selling, offering for
469 | sale, or importing the Program or any portion of it.
470 | 
471 |   11. Patents.
472 | 
473 |   A "contributor" is a copyright holder who authorizes use under this
474 | License of the Program or a work on which the Program is based.  The
475 | work thus licensed is called the contributor's "contributor version".
476 | 
477 |   A contributor's "essential patent claims" are all patent claims
478 | owned or controlled by the contributor, whether already acquired or
479 | hereafter acquired, that would be infringed by some manner, permitted
480 | by this License, of making, using, or selling its contributor version,
481 | but do not include claims that would be infringed only as a
482 | consequence of further modification of the contributor version.  For
483 | purposes of this definition, "control" includes the right to grant
484 | patent sublicenses in a manner consistent with the requirements of
485 | this License.
486 | 
487 |   Each contributor grants you a non-exclusive, worldwide, royalty-free
488 | patent license under the contributor's essential patent claims, to
489 | make, use, sell, offer for sale, import and otherwise run, modify and
490 | propagate the contents of its contributor version.
491 | 
492 |   In the following three paragraphs, a "patent license" is any express
493 | agreement or commitment, however denominated, not to enforce a patent
494 | (such as an express permission to practice a patent or covenant not to
495 | sue for patent infringement).  To "grant" such a patent license to a
496 | party means to make such an agreement or commitment not to enforce a
497 | patent against the party.
498 | 
499 |   If you convey a covered work, knowingly relying on a patent license,
500 | and the Corresponding Source of the work is not available for anyone
501 | to copy, free of charge and under the terms of this License, through a
502 | publicly available network server or other readily accessible means,
503 | then you must either (1) cause the Corresponding Source to be so
504 | available, or (2) arrange to deprive yourself of the benefit of the
505 | patent license for this particular work, or (3) arrange, in a manner
506 | consistent with the requirements of this License, to extend the patent
507 | license to downstream recipients.  "Knowingly relying" means you have
508 | actual knowledge that, but for the patent license, your conveying the
509 | covered work in a country, or your recipient's use of the covered work
510 | in a country, would infringe one or more identifiable patents in that
511 | country that you have reason to believe are valid.
512 | 
513 |   If, pursuant to or in connection with a single transaction or
514 | arrangement, you convey, or propagate by procuring conveyance of, a
515 | covered work, and grant a patent license to some of the parties
516 | receiving the covered work authorizing them to use, propagate, modify
517 | or convey a specific copy of the covered work, then the patent license
518 | you grant is automatically extended to all recipients of the covered
519 | work and works based on it.
520 | 
521 |   A patent license is "discriminatory" if it does not include within
522 | the scope of its coverage, prohibits the exercise of, or is
523 | conditioned on the non-exercise of one or more of the rights that are
524 | specifically granted under this License.  You may not convey a covered
525 | work if you are a party to an arrangement with a third party that is
526 | in the business of distributing software, under which you make payment
527 | to the third party based on the extent of your activity of conveying
528 | the work, and under which the third party grants, to any of the
529 | parties who would receive the covered work from you, a discriminatory
530 | patent license (a) in connection with copies of the covered work
531 | conveyed by you (or copies made from those copies), or (b) primarily
532 | for and in connection with specific products or compilations that
533 | contain the covered work, unless you entered into that arrangement,
534 | or that patent license was granted, prior to 28 March 2007.
535 | 
536 |   Nothing in this License shall be construed as excluding or limiting
537 | any implied license or other defenses to infringement that may
538 | otherwise be available to you under applicable patent law.
539 | 
540 |   12. No Surrender of Others' Freedom.
541 | 
542 |   If conditions are imposed on you (whether by court order, agreement or
543 | otherwise) that contradict the conditions of this License, they do not
544 | excuse you from the conditions of this License.  If you cannot convey a
545 | covered work so as to satisfy simultaneously your obligations under this
546 | License and any other pertinent obligations, then as a consequence you may
547 | not convey it at all.  For example, if you agree to terms that obligate you
548 | to collect a royalty for further conveying from those to whom you convey
549 | the Program, the only way you could satisfy both those terms and this
550 | License would be to refrain entirely from conveying the Program.
551 | 
552 |   13. Use with the GNU Affero General Public License.
553 | 
554 |   Notwithstanding any other provision of this License, you have
555 | permission to link or combine any covered work with a work licensed
556 | under version 3 of the GNU Affero General Public License into a single
557 | combined work, and to convey the resulting work.  The terms of this
558 | License will continue to apply to the part which is the covered work,
559 | but the special requirements of the GNU Affero General Public License,
560 | section 13, concerning interaction through a network will apply to the
561 | combination as such.
562 | 
563 |   14. Revised Versions of this License.
564 | 
565 |   The Free Software Foundation may publish revised and/or new versions of
566 | the GNU General Public License from time to time.  Such new versions will
567 | be similar in spirit to the present version, but may differ in detail to
568 | address new problems or concerns.
569 | 
570 |   Each version is given a distinguishing version number.  If the
571 | Program specifies that a certain numbered version of the GNU General
572 | Public License "or any later version" applies to it, you have the
573 | option of following the terms and conditions either of that numbered
574 | version or of any later version published by the Free Software
575 | Foundation.  If the Program does not specify a version number of the
576 | GNU General Public License, you may choose any version ever published
577 | by the Free Software Foundation.
578 | 
579 |   If the Program specifies that a proxy can decide which future
580 | versions of the GNU General Public License can be used, that proxy's
581 | public statement of acceptance of a version permanently authorizes you
582 | to choose that version for the Program.
583 | 
584 |   Later license versions may give you additional or different
585 | permissions.  However, no additional obligations are imposed on any
586 | author or copyright holder as a result of your choosing to follow a
587 | later version.
588 | 
589 |   15. Disclaimer of Warranty.
590 | 
591 |   THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
592 | APPLICABLE LAW.  EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
593 | HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY
594 | OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO,
595 | THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
596 | PURPOSE.  THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM
597 | IS WITH YOU.  SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
598 | ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
599 | 
600 |   16. Limitation of Liability.
601 | 
602 |   IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
603 | WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
604 | THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
605 | GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
606 | USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
607 | DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
608 | PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
609 | EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
610 | SUCH DAMAGES.
611 | 
612 |   17. Interpretation of Sections 15 and 16.
613 | 
614 |   If the disclaimer of warranty and limitation of liability provided
615 | above cannot be given local legal effect according to their terms,
616 | reviewing courts shall apply local law that most closely approximates
617 | an absolute waiver of all civil liability in connection with the
618 | Program, unless a warranty or assumption of liability accompanies a
619 | copy of the Program in return for a fee.
620 | 
621 |                      END OF TERMS AND CONDITIONS
622 | 
623 |             How to Apply These Terms to Your New Programs
624 | 
625 |   If you develop a new program, and you want it to be of the greatest
626 | possible use to the public, the best way to achieve this is to make it
627 | free software which everyone can redistribute and change under these terms.
628 | 
629 |   To do so, attach the following notices to the program.  It is safest
630 | to attach them to the start of each source file to most effectively
631 | state the exclusion of warranty; and each file should have at least
632 | the "copyright" line and a pointer to where the full notice is found.
633 | 
634 |     <one line to give the program's name and a brief idea of what it does.>
635 |     Copyright (C) <year>  <name of author>
636 | 
637 |     This program is free software: you can redistribute it and/or modify
638 |     it under the terms of the GNU General Public License as published by
639 |     the Free Software Foundation, either version 3 of the License, or
640 |     (at your option) any later version.
641 | 
642 |     This program is distributed in the hope that it will be useful,
643 |     but WITHOUT ANY WARRANTY; without even the implied warranty of
644 |     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
645 |     GNU General Public License for more details.
646 | 
647 |     You should have received a copy of the GNU General Public License
648 |     along with this program.  If not, see <http://www.gnu.org/licenses/>.
649 | 
650 | Also add information on how to contact you by electronic and paper mail.
651 | 
652 |   If the program does terminal interaction, make it output a short
653 | notice like this when it starts in an interactive mode:
654 | 
655 |     <program>  Copyright (C) <year>  <name of author>
656 |     This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
657 |     This is free software, and you are welcome to redistribute it
658 |     under certain conditions; type `show c' for details.
659 | 
660 | The hypothetical commands `show w' and `show c' should show the appropriate
661 | parts of the General Public License.  Of course, your program's commands
662 | might be different; for a GUI interface, you would use an "about box".
663 | 
664 |   You should also get your employer (if you work as a programmer) or school,
665 | if any, to sign a "copyright disclaimer" for the program, if necessary.
666 | For more information on this, and how to apply and follow the GNU GPL, see
667 | <http://www.gnu.org/licenses/>.
668 | 
669 |   The GNU General Public License does not permit incorporating your program
670 | into proprietary programs.  If your program is a subroutine library, you
671 | may consider it more useful to permit linking proprietary applications with
672 | the library.  If this is what you want to do, use the GNU Lesser General
673 | Public License instead of this License.  But first, please read
674 | <http://www.gnu.org/philosophy/why-not-lgpl.html>.
675 | 


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