[Tcl-bugs] [ tcl-Bugs-1490503 ] regexp within foreach loop matches wrong

[SourceForge.net <no...@so...>]

Bugs item #1490503, was opened at 2006-05-17 21:30
Message generated for change (Settings changed) made by dkf
You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=110894&aid=1490503&group_id=10894

Please note that this message will contain a full copy of the comment thread,
including the initial issue submission, for this request,
not just the latest update.
>Category: 46. Bytecode Compiler
Group: current: 8.4.13
Status: Closed
Resolution: Invalid
Priority: 5
Submitted By: AVZ (sachulka)
Assigned to: miguel sofer (msofer)
Summary: regexp within foreach loop matches wrong

Initial Comment:
I recently upgraded from Tcl8.3 to Tcl8.4.13 on 
solaris and discovered this difference which does not 
seem right. 

here is my little program:

proc send_user { x } { puts $x }
set alarmRecord [list "abc: def" "ALARM 1: blah" "ghi: 
jkl" "ALARM 2: fjdasl"]
foreach record $alarmRecord {
   if [regexp {(ALARM)[^:]+([0-9]+)} $record match key 
value] {
      send_user ">KEY $key VALUE $value\n"
   } elseif [regexp {([^:]+):(.*)} $record match key 
value]  {
      send_user "KEY2 $key VALUE $value\n"
   }
} 

Here are the results, the key and value are different 
for different Tcl versions:
sapphire:~/thuyscripts {ewuthle_eusbd00250}> tclsh8.3
KEY2 abc VALUE  def
 
>KEY ALARM VALUE 1
 
KEY2 ghi VALUE  jkl
 
>KEY ALARM VALUE 2

sapphire:~/thuyscripts {ewuthle_eusbd00250}> tclsh
% info tclversion
8.4
KEY2 abc VALUE  def
 
>KEY ALARM 1 VALUE  blah
 
KEY2 ghi VALUE  jkl
 
>KEY ALARM 2 VALUE  fjdasl

So if regexp is in the foreach loop and the same 
variables (key/value) are used inside if - regexp does 
not match correctly.



----------------------------------------------------------------------

Comment By: Nobody/Anonymous (nobody)
Date: 2006-05-18 08:57

Message:
Logged In: NO 

See also bug 219166, it was fixed in 8.4a4


----------------------------------------------------------------------

Comment By: miguel sofer (msofer)
Date: 2006-05-17 21:59

Message:
Logged In: YES 
user_id=148712

The bug is actually in Tcl8.3 (although I did not confirm
the behaviour there), the behaviour in 8.4 is correct.

Your script is missing some braces in order to perform
according to your expectation: it should be

  if {[regexp ...]} {
      send_user ">KEY $key VALUE $value\n"
  } elseif {[regexp ...] {
      send_user "KEY2 $key VALUE $value\n"
  }

Please note that the conditions to 'if ... elseif' are
enclosed in braces. This means that they are passed to 'if'
as strings; when 'if' evals the first condition and finds it
is true, it never evaluates the second.

In your script as posted, both regexp's are evaluated
*before* they are passed as arguments to 'if'; so, even when
the first regexp matches, the values $key and $value are set
by the second regexp.

----------------------------------------------------------------------

You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=110894&aid=1490503&group_id=10894