Class: Strling::Emitters::PCRE2

Inherits:
Object
  • Object
show all
Defined in:
lib/strling/emitters/pcre2.rb

Overview

PCRE2 emitter class

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(flags) ⇒ PCRE2

Returns a new instance of PCRE2.



35
36
37
 
# File 'lib/strling/emitters/pcre2.rb', line 35

def initialize(flags)
  @flags = flags
end

Class Method Details

.build_flags(flags) ⇒ Object

Build flag string from Flags object



81
82
83
84
85
86
87
88
89
 
# File 'lib/strling/emitters/pcre2.rb', line 81

def self.build_flags(flags)
  str = ''
  str += 'i' if flags.ignore_case
  str += 'm' if flags.multiline
  str += 's' if flags.dot_all
  str += 'u' if flags.unicode
  str += 'x' if flags.extended
  str
end

.emit(ir_root, flags) ⇒ String

Emit IR as a PCRE2 regex pattern

Parameters:

  • ir_root (IROp) —

    The root IR node

  • flags (Flags) —

    The pattern flags

Returns:

  • (String) —

    The PCRE2 regex pattern



26
27
28
29
30
31
32
33
 
# File 'lib/strling/emitters/pcre2.rb', line 26

def self.emit(ir_root, flags)
  emitter = new(flags)
  pattern = emitter.emit_node(ir_root)
  
  # Add flag modifiers if any
  flag_str = build_flags(flags)
  flag_str.empty? ? pattern : "(?#{flag_str})#{pattern}"
end

Instance Method Details

#emit_node(node) ⇒ String

Emit a single IR node

Parameters:

  • node (IROp) —

    The IR node to emit

Returns:

  • (String) —

    The PCRE2 pattern fragment



43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
 
# File 'lib/strling/emitters/pcre2.rb', line 43

def emit_node(node)
  case node
  when Strling::Core::IRAlt, Strling::IR::Alt
    # (branch1|branch2|...)
    branches = node.branches.map { |b| emit_node(b) }
    branches.length == 1 ? branches[0] : "(#{branches.join('|')})"
  when Strling::Core::IRSeq, Strling::IR::Seq
    # Concatenate parts
    node.parts.map { |p| emit_node(p) }.join
  when Strling::Core::IRLit, Strling::IR::Lit
    # Escape metacharacters
    escape_literal(node.value)
  when Strling::Core::IRDot, Strling::IR::Dot
    '.'
  when Strling::Core::IRAnchor, Strling::IR::Anchor
    emit_anchor(node.at)
  when Strling::Core::IRCharClass, Strling::IR::CharClass
    emit_char_class(node)
  when Strling::Core::IRQuant, Strling::IR::Quant
    emit_quantifier(node)
  when Strling::Core::IRGroup, Strling::IR::Group
    emit_group(node)
  when Strling::Core::IRBackref
    emit_backref(node)
  when Strling::IR::BackRef
    emit_backref(node)
  when Strling::Core::IRLook, Strling::IR::Look
    emit_lookaround(node)
  when Strling::IR::Esc
    emit_escape(node)
  else
    raise "Unknown IR node type: #{node.class}"
  end
end