Making it regex only

^ #start of line
    ([a-zA-Z\-\_0-9\.]+) # key regex
\: # colon to separate from value
   # ([a-zA-Z]+:)? # Delimiter regex
    # value regex

• Correctly matches non-delimited keys & values

  • ([a-z]+):((?:(?:.|\n|\r)(?!^[a-z]+:))+)

• Correctly matches delimited keys & values

  • ([a-z]+):([A-Z]:)((.|\r|\n))^:\2

• Matches everything correctly, BUT references are not right

  • (?:(?:([a-z]+):([A-Z]:)((.|\r|\n))^:\2)|([a-z]+):((?:(?:.|\n|\r)(?!^[a-z]+:))+))
  • (?|(?:(?:([a-z]+):([A-Z]:)((.|\r|\n))^:\2))|(([a-z]+):((?:(?:.|\n|\r)(?!^[a-z]+:))+)))

• Matches everything and gives me victory:

Deconstruction

# non-delimiting regex
^([a-z]+) # key
 :
 ((?:
    (?:.|\n|\r) # characters we want
    (?!^[a-z]+:) # But NOT if those characters make up a key
 )+)

# Delimiting regex

^([a-z]+) # key
:
([A-Z]*:) # delimiter
((.|\r|\n)*) # characters we want
^:\2 # Ends with delimiter


# Caputure all (#2)
^([a-z]+): # key CP#1
    ((?:[A-Z]*:)? # delimiter, optional
        (?:\s*(\r?\n|$)) # whitespace, new line OR end of file (line?)
    ) # CP#2
    (    # value, CP#3
        (?:(?:
            (?:.|\n|\r) # characters we want
            (?!^[a-z]+:) # But NOT if those characters make up a key
        )+)          
    | # or
        
        ((.|\r|\n)*) # characters we want
        ^:\2 # Ends with delimiter

    )           # delimited value


# Caputre all (hopefully)
^([a-z]+): # key
    (    # Non-delimited value
        (?:(?:
            (?:.|\n|\r) # characters we want
            (?!^[a-z]+:) # But NOT if those characters make up a key
        )+)          
    | # or
        ([A-Z]*:) # delimiter
        ((.|\r|\n)*) # characters we want
        ^:\2 # Ends with delimiter

    )           # delimited value



# non-delimiting WITHOUT lookahead
 ^([a-z]+) # key
 :
 ((?:
    (?:.|\n|\r) # characters we want
 )+)
 (([a-z]+):|$)

^([a-z]+):((?:(?:.|\n|\r))+)(([a-z]+):|$)

Testing against this, to setup delimiting

key: value 1
nightmare:DELIM:
notakey:
obviously not a key
notakey:
:DELIM:
abc: value 2
new line
anotherkey: value 3

^([a-zA-Z-_0-9.]+):((.|\n|\r)(?!^[a-zA-Z0-9]:))+

abc:value abc2: value abc3: value blah cat dog 3284790871345&^(&^$!@#$@#^_()*#@$!
abc4: one two three

abc.x-y_z.5: x abc fasdf blah

cat.dog:DELIM: notakey1: value notakey2: value not.a.key: valuv vall :DELIM: