Hello everyone, I am having some trouble understanding leex behaviour. To give some context, I would like to create a parser for pgn files. Here is some code to explain my problem. I created the lexer file pgn_lexer.xrl with % -- Definitions. Definitions. TAG = (\[[^\]]*\])+ COMMENT …

[image] kip: The reason is that regexes in Leex are greedy Yes, they are greedy, but thats not the cause here. TAG is defined as (\[[^\]]*\])+ and thus we demand at least one but allow many repitions of square-bracket-pairs-with-stuff-inbetween and consolidate them into one token. If the se…

The reason is that regexes in Leex are greedy. Your regex in this case matches the longest string possible. Here’s a example using your regex and data in IEx: iex> r = ~r/(\[[^\]]*\])+/ ~r/(\[[^\]]*\])+/ iex> String.split "[Tag1 \"Value1\"] [Tag2 \"Value2\"]{comment}", r, include_captures: true …

That did the trick, thank You very much. Here is the modified version… TAG = (\[[^\]]*\]) iex> :pgn_lexer.string '[Tag1 "Value1"][Tag2 "Value2"]{comment}' {:ok, [ {:tag, 1, '[Tag1 "Value1"]'}, {:tag, 1, '[Tag2 "Value2"]'}, {:comment, 1, '{comment}'} ], 1} And as mentionned, th…

Arrrggghhhhh sorry for my misleading reply.

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Leex regex problem

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kokolegorille April 10, 2018, 9:25pm 3

Thank You for the answer, now I know why, and I know why I am spending hours too