ID:               45111
 User updated by:  php at koterov dot ru
 Reported By:      php at koterov dot ru
 Status:           Open
 Bug Type:         Feature/Change Request
 Operating System: all
 PHP Version:      5.2.6
 New Comment:

I have dug the PHP source code a little.

Hmm, seems this feature is not too easy to implement...

Line number is stored in znode, it's easy to substitute. But filename
is stored in zend_op_array, NOT in zend_op. So, for a sequence of
opcodes grouped by a single zend_op_array there is no chance to specify
different filenames. (Of course I could add a field to zend_op, but in
this case all accelerators like eAccelerator seem to stop working,
because they know nothing about this field and do not store/restore
it.)

Am I right?


Previous Comments:
------------------------------------------------------------------------

[2008-05-27 22:54:09] php at koterov dot ru

Description:
------------
In Perl, we could write the following program test.pl (lines are
enumerated for better look):

01  #!/usr/bin/perl -w
02  print "hello!\n";
03  print "something!\n";
04
05  #line 100 "aaa.pl"
06  print $undefined_var;

This code generates a warning message "Using of undefined variable",
but (attention!) - the context of this error is NOT "test.pl line 5",
but - "aaa.pl line 100".

So, the "pseudo-comment" operator

#line xxx "yyy"

in Perl substitutes the current parsing context to a specified line
number and filename. (You may ommit filename, then - only the line
number will be substituted). And, if a warning or a fatal error occurs,
the line number and filename in the error message will be changed. There
is the same feature in C language: it is used by C preprocessor to
execute #include directives an keep line numbers clear to understand.

This feature is VERY VERY useful when we write some code translator
(e.g. from a templating language to pure PHP). This kind of translation
is done e.g. in Smarty: it translates Smarty templates into pure PHP
code, but line numbers are mixed up in translated files, so we cannot
revert back and detect which line of the template had produced an
error.

Please say, do you plan to add this feature to a new PHP versions? I'd
like to ask you very much about it...




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