[erlang-questions] How best to resolve apparent inconsistency between re:run and string:slice

[Scott Finnie]

Hello all



I discovered an apparent inconsistency between re:run/2 and string:slice/2 last night.  I'd appreciate any suggestions on the right way to solve.  Best illustrated by this example:



1> S1="\rDogs".

"\rDogs"

2> S2="\r\nDogs".

"\r\nDogs"

3> {match, [{_, To1}]}=re:run(S1, "^\r").

{match,[{0,1}]}

4> {match, [{_, To2}]}=re:run(S2, "^\r\n").

{match,[{0,2}]}

5> string:slice(S1,To1).

"Dogs"

6> string:slice(S2,To2).

"ogs"



I'd guess this is due to string:slice treating "\r\n" as a single lexeme, whereas re:run treats it as two characters.



What I'm trying to achieve is consistent behaviour that (a) recognises any newline (CR, LF, CRLF, ...) at the start of the string and removes it.  I also need a count of the contiguous newlines found.



As an aside, the now-obsolete string:sub_string/2 does seem to work consistently:



7> string:sub_string(S1,To1+1).

"Dogs"

8> string:sub_string(S2,To2+1).

"Dogs"



Thanks,

Scott.

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