Module: Suma::ExpressReformatter

Defined in:
lib/suma/express_reformatter.rb

Overview

Reformats EXPRESS source into suma's canonical form: comment blocks (the (*"...\n*) remarks that EXPRESS uses for documentation) are extracted from their inline positions and appended to the end of the file, and excess blank lines are collapsed.

Pure content transformation — no I/O, no Thor, no filesystem. The CLI adapter handles reading from and writing to disk.

The transform is idempotent: reformatting an already-reformatted document returns changed?: false.

Comment extraction uses String#index rather than a single m-mode regex. The original /\(\*"(.*?)\n\*\)/m is correct functionally but is polynomial-time on adversarial input (CodeQL rb/polynomial-redos). Scanning for the start marker, then for the next terminator, is unambiguously linear.

Defined Under Namespace

Classes: Result

Constant Summary collapse

COMMENT_START = 
'(*"'
COMMENT_END = 
"\n*)"
BLANK_RUN_PATTERN = 
/(\n\n+)/
NEWLINE_RUN_PATTERN = 
/(\n+)/

Class Method Summary collapse

Class Method Details

.call(content) ⇒ Object 



34
35
36
37
38
39
40
41
42
43
44
45
46
 
# File 'lib/suma/express_reformatter.rb', line 34

def call(content)
  comments = extract_comments(content)
  return Result.new(content: content, changed?: false) if comments.empty?

  without_comments = strip_comments(content)
  new_comments = comments.map { |c| "#{COMMENT_START}#{c}#{COMMENT_END}" }
    .join("\n\n")
  new_content = "#{without_comments}\n\n#{new_comments}\n"
  new_content = new_content.gsub(BLANK_RUN_PATTERN, "\n\n")

  changed = normalised_compare(content, new_content) != 0
  Result.new(content: new_content, changed?: changed)
end

.each_comment_range(content) ⇒ Object 



74
75
76
77
78
79
80
81
82
83
84
85
86
 
# File 'lib/suma/express_reformatter.rb', line 74

def each_comment_range(content)
  return enum_for(:each_comment_range, content) unless block_given?

  pos = 0
  while (start_idx = content.index(COMMENT_START, pos))
    end_idx = content.index(COMMENT_END, start_idx + COMMENT_START.length)
    break unless end_idx

    yield pre_start: pos, start: start_idx,
          end_exclusive: end_idx + COMMENT_END.length
    pos = end_idx + COMMENT_END.length
  end
end

.extract_comments(content) ⇒ Object 



48
49
50
51
52
53
54
55
56
57
58
59
 
# File 'lib/suma/express_reformatter.rb', line 48

def extract_comments(content)
  comments = []
  pos = 0
  while (start_idx = content.index(COMMENT_START, pos))
    end_idx = content.index(COMMENT_END, start_idx + COMMENT_START.length)
    break unless end_idx

    comments << content[(start_idx + COMMENT_START.length)...end_idx]
    pos = end_idx + COMMENT_END.length
  end
  comments
end

.strip_comments(content) ⇒ Object 



61
62
63
64
65
66
67
68
69
70
71
72
 
# File 'lib/suma/express_reformatter.rb', line 61

def strip_comments(content)
  return content unless content.index(COMMENT_START, 0)

  stripped = +""
  last_end = 0
  each_comment_range(content) do |range|
    stripped << content[range[:pre_start]...range[:start]]
    last_end = range[:end_exclusive]
  end
  stripped << content[last_end..]
  stripped.force_encoding(content.encoding)
end