[TxMt] Re: Conditional regex
mummer at whitefalls.org
Sun May 24 20:32:16 UTC 2009
On May 22, 2009, at 12:56 PM, Dijk van Marc wrote:
> The situation:
> A PDB file is essentially a table. One line from such a table can be
> as follows:
> ATOM 14 CA GLN A 2 -27.648 -9.581 30.325 1.00 10.00
> In the language description I would like to use a regular expression
> construct that
> matched 'GLN' only if the line starts with either 'ATOM' or
> 'HETATM'. This seams like
> a conditional regular expression but my attempts to implement it at
> such have failed
> so far.
Start a begin/end match with a look-ahead on ATOM|HETATM:
And an end of $ (end of line). Inside the pattern rules have a match
for the GLN.
You could use a conditional regex to do this if it was before the
ATOM, but you can't do look-behinds of an unspecified length.
More information about the textmate