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From: Jean-Louis Leroy <jll@skynet.be>
Newsgroups: comp.lang.beta
Subject: Sif crashes on this
Date: Sun, 13 Dec 1998 15:47:28 +0100
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Xref: news.cs.au.dk comp.lang.beta:11750

Hello,

I'm trying to figure out the BETA equivalent of calling a function through a pointer. I 
don't have the BETA book yet, and the tutorials don't seem to address the question. 
While playing around I discovered that attempting to compile:

ORIGIN '~beta/basiclib/v1.6/betaenv';
-- program: Descriptor --
(#
   fun: (#  exit 666 #);
   fptr: ##fun;
   f1: fun (#  exit 1 #);
   f2: (#  exit 2 #)
do f1##->fptr##
#)  

...as the body of a new program crashes Sif with the following message:

<SIF>

Sif - Mjolner Browser and Editor version 5.2(0) nti
      integrated with BETA Compiler version 5.3(4)
Calling BETA compiler
-------------------------------------------------------------------------------
No qua-check warnings and .lst file
Target machine type nti(ms)
Building dependency graph for: 'k:\beta\start\fptr\fptr' ...
Translating fragments ...
Bind fragments in: 'k:\beta\start\fptr\fptr'Code generation
DescRef is null! Fatal error
f1

</SIF>

I compiled from the command line, and the compiler crashed as well. Here's the resulting 
beta.dump file:

<DUMPFILE>

Beta execution aborted: Reference is none.

Call chain: (nti)

  item <putText#>putText# in ~beta/betaast/v5.2/private/indeximpl
    -- outputStream#output# in ~beta/betaast/v5.2/private/indeximpl
  item <*> in ~beta/pretty/v5.2/private/token
    -- Output# in ~beta/pretty/v5.2/private/token
  item <Output#> in ~beta/pretty/v5.2/private/token
    -- Token# in ~beta/pretty/v5.2/private/token
  item <PRINTER-~> in ~beta/pretty/v5.2/private/printer
    -- Viewer# in ~beta/pretty/v5.2/astviewer
  item <Advanceleft#> in ~beta/pretty/v5.2/private/scanner
    -- SCANNER-~ in ~beta/pretty/v5.2/private/scanner
  item <finish#> in ~beta/pretty/v5.2/private/scanner
    -- SCANNER-~ in ~beta/pretty/v5.2/private/scanner
  item <UNPARSER-~> in ~beta/pretty/v5.2/private/unparser
    -- Viewer# in ~beta/pretty/v5.2/astviewer
  item <DOPRESENT-~> in ~beta/pretty/v5.2/private/ppimpl
    -- present# in ~beta/pretty/v5.2/astviewer
  item <present#> in ~beta/pretty/v5.2/astviewer
    -- Viewer# in ~beta/pretty/v5.2/astviewer
  item <PRETTYPRINTERBODY-~> in ~beta/betaast/v5.2/private/indeximpl
    -- prettyPrinter# in ~beta/betaast/v5.2/index
  item <prettyPrinter#> in ~beta/betaast/v5.2/index
    -- *astInterface# in ~beta/compiler/control/systembody
  item <thePP#> in ~beta/compiler/control/systembody
    -- compiler# in ~beta/compiler/control/system
  item <Descrip#> in ~beta/compiler/checker/semattbody
    -- SEMATT-~ in ~beta/compiler/checker/sematt
  item strucRef#<StrucRef#> in ~beta/compiler/checker/sematt
    -- *EvCase# in ~beta/compiler/synthesizer/evbody
  item <EVCASE-~> in ~beta/compiler/checker/semattbody
    -- *EvCase# in ~beta/compiler/synthesizer/evbody
  item *<EvCase#> in ~beta/compiler/checker/sematt
    -- SEMATT-~ in ~beta/compiler/checker/sematt
  item <EXPEVAL-~> in ~beta/compiler/synthesizer/evbody
    -- ExpEval# in ~beta/compiler/synthesizer/synthlib
  item <ExpEval#> in ~beta/compiler/synthesizer/synthlib
    -- EvalHandler# in ~beta/compiler/synthesizer/synthlib
  item <assign#>binEv# in ~beta/compiler/synthesizer/evbody
    -- *EvCase# in ~beta/compiler/synthesizer/evbody
  item <EVCASE-~> in ~beta/compiler/checker/semattbody
    -- *EvCase# in ~beta/compiler/synthesizer/evbody
  item *<EvCase#> in ~beta/compiler/checker/sematt
    -- SEMATT-~ in ~beta/compiler/checker/sematt
  item <EVALBODY-~> in ~beta/compiler/synthesizer/evbody
    -- GenEval# in ~beta/compiler/synthesizer/synthlib
  item <GenEval#> in ~beta/compiler/synthesizer/synthlib
    -- EvalHandler# in ~beta/compiler/synthesizer/synthlib
  item <*> in ~beta/compiler/synthesizer/dobody
    -- *scanList# in ~beta/compiler/synthesizer/dobody
  item <*>scanList# in ~beta/compiler/synthesizer/dobody
    -- Scan# in ~beta/compiler/synthesizer/dobody
  item <Scan#> in ~beta/compiler/synthesizer/dobody
    -- * in ~beta/compiler/synthesizer/dobody
  item <*> in ~beta/compiler/synthesizer/dobody
    -- GenDo# in ~beta/compiler/synthesizer/genlib
  item <GenDo#> in ~beta/compiler/synthesizer/dobody
    -- theGen# in ~beta/compiler/synthesizer/synthesizer
  item <GenObj#> in ~beta/compiler/synthesizer/genlib
    -- theGen# in ~beta/compiler/synthesizer/synthesizer
  item <GENDESCBODY-~> in ~beta/compiler/synthesizer/gdbody
    -- GenDesc# in ~beta/compiler/synthesizer/synthesizer
  item <GenDesc#> in ~beta/compiler/synthesizer/synthesizer
    -- theGen# in ~beta/compiler/synthesizer/synthesizer
  item <body#> in ~beta/compiler/synthesizer/synthesizer
    -- SYNTHESIZER-~ in ~beta/compiler/synthesizer/synthesizer
  item <SYNTHESIZER-~> in ~beta/compiler/synthesizer/synthesizer
    -- Synthesizer# in ~beta/compiler/control/system
  item <Synthesizer#> in ~beta/compiler/control/system
    -- compiler# in ~beta/compiler/control/system
  item <DoTheCodeGen#> in ~beta/compiler/control/translate_controlbody
    -- xcontroller#ScanNonCompiled#scanner# in ~beta/compiler/control/translate
  item <*> in ~beta/compiler/control/translate_controlbody
    -- Translate#translate# in ~beta/compiler/control/translate
  item <Translate#>translate# in ~beta/compiler/control/translate_controlbody
    -- xcontroller#ScanNonCompiled#scanner# in ~beta/compiler/control/translate
  item <translate#>Translate# in ~beta/dependency/v1.3/private/scannoncompiledbody
    -- *controller# in ~beta/dependency/v1.3/private/scannoncompiledbody
  item <*>ScanAndClear# in ~beta/dependency/v1.3/private/controlbody
    -- TransList#SimpleList# in ~beta/dependency/v1.3/private/dependencybody
  item <CONTROLLERPRIVATE-~> in ~beta/dependency/v1.3/private/controlbody
    -- *controller# in ~beta/dependency/v1.3/private/scannoncompiledbody
  item *<controller#> in ~beta/dependency/v1.3/private/dependencybody
    -- xcontroller#ScanNonCompiled#scanner# in ~beta/compiler/control/translate
  item xcontroller#<ScanNonCompiled#>scanner# in 
~beta/dependency/v1.3/private/scannoncompiledbody
    -- depGraph#DependencyGraph# in ~beta/compiler/control/translate
  item <TRANSLATEDOBODY-~> in ~beta/compiler/control/translatebody
    -- TRANSLATE-~ in ~beta/compiler/control/translate
  item <TRANSLATE-~> in ~beta/compiler/control/translate
    -- compiler# in ~beta/compiler/control/system
  item <SYSTEMTRANSLATEBODY-~> in ~beta/compiler/control/systembody
    -- *translate# in ~beta/compiler/control/interactive
  item *<translate#> in ~beta/compiler/control/system
    -- compiler# in ~beta/compiler/control/system
  item <activateCompiler#> in ~beta/compiler/control/interactive
    -- interactiveCompiler# in ~beta/compiler/control/interactive
  item <interactiveCompiler#> in ~beta/compiler/control/interactive
    -- PROGRAM-~SystemEnv#SysHead# in ~beta/compiler/beta
  comp <PROGRAM-~>SystemEnv#SysHead# in ~beta/compiler/beta
    -- BETAENV-~ in ~beta/basiclib/v1.6/betaenv


  item <attNext#>realValue# in ~beta/basiclib/v1.6/private/basicsystemenvbody
    -- BASICSYSTEMENVPRIVATE-~ in ~beta/basiclib/v1.6/private/basicsystemenvbody
  item <*>cycle# in ~beta/basiclib/v1.6/private/systemenv_ntbody
    -- BASICSCHEDULER-~ in ~beta/basiclib/v1.6/private/systemenv_ntbody
  comp <BASICSCHEDULER-~> in ~beta/basiclib/v1.6/private/systemenv_ntbody
    -- PROGRAM-~SystemEnv#SysHead# in ~beta/compiler/beta


  basic component in ~beta/basiclib/v1.6/betaenv


Legend:
    <<snipped>>
    
</DUMPFILE>

BTW, what's the solution to my original problem?

Jean-Louis Leroy
http://ourworld.compuserve.com/homepages/jl_leroy/