[GHC] #2946: tracing should be controled by a global flag (it should not be resume context specific)

[GHC]

#2946: tracing should be controled by a global flag (it should not be resume
context specific)
---------------------------------+------------------------------------------
    Reporter:  phercek           |        Owner:                  
        Type:  feature request   |       Status:  new             
    Priority:  normal            |    Milestone:  6.12 branch     
   Component:  GHCi              |      Version:  6.10.1          
    Severity:  minor             |   Resolution:                  
    Keywords:  debugger          |   Difficulty:  Unknown         
    Testcase:                    |           Os:  Unknown/Multiple
Architecture:  Unknown/Multiple  |  
---------------------------------+------------------------------------------
Comment (by phercek):

 I asked for ":force <expr>" in the second bullet of the ticket
 description. It was an insight by accident. It would be really cool if we
 could force expressions and not only a list of variables. The main reason
 is user defined conditional breakpoints. A breakpoint condition may
 contain thunks which need to be forced to compute the condition result.
 This may result in hitting other breakpoints in nested contexts. This may
 be required or not. It depends, but it is almost never required if we
 query some expression containing _result variable. The problem is we stop
 at the same breakpoint we are just now at. With ":foce <expr>" we could
 force the breakpoint stop condition first and then query its result by
 checking the "it" variable.[[BR]]
 This is convenient for scripts, not that interesting for manual
 interaction. But scripts can disable breakpoints before evaluating the
 stop condition and enable them after the condition evaluation finished so
 there is a workaround. I just did not add :enable and :disable to my .ghci
 yet :-/

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/2946#comment:4>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler