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Edit detail for SandBox Cast revision 2 of 2

1 2
Editor: Bill Page
Time: 2009/10/13 16:58:25 GMT-7
Note: update

added:

The follow commands are run using FriCAS
\begin{axiom}
)version
\end{axiom}

changed:
-This command causes a "memory may be damaged error"::
-
-  !\begin{axiom}
-  cast1(1)$CAST
-  \end{axiom}
This command used to cause a "memory may be damaged" error::

\begin{axiom}
 cast1(1)$CAST
\end{axiom}

changed:
-This command also causes a "memory may be damaged error"::
-
-  !\begin{axiom}
-  cast2(1)
-  \end{axiom}
-
This command also used cause a "memory may be damaged" error::

\begin{axiom}
 cast2(1)
\end{axiom}


This is an example of using pretend to perform a type unsafe operation.

The follow commands are run using FriCAS

fricas
)version
Value = "FriCAS 1.3.7 compiled at Wed Jun 30 16:44:06 UTC 2021"

spad
)abbrev package CAST cast
cast(): exports == implementation where
exports == with
cast1: Integer -> Float
implementation == add
cast1(i:Integer):Float == j:Float := (i pretend Float)
spad
   Compiling FriCAS source code from file 
      /var/lib/zope2.10/instance/axiom-wiki/var/LatexWiki/76482798552469661-25px002.spad
      using old system compiler.
   CAST abbreviates package cast 
------------------------------------------------------------------------
   initializing NRLIB CAST for cast 
   compiling into NRLIB CAST 
   compiling exported cast1 : Integer -> Float
      CAST;cast1;IF;1 is replaced by LETji 
Time: 0 SEC.
(time taken in buildFunctor: 0)
;;; *** |cast| REDEFINED
;;; *** |cast| REDEFINED Time: 0 SEC.
Cumulative Statistics for Constructor cast Time: 0 seconds
finalizing NRLIB CAST Processing cast for Browser database: --->-->cast(constructor): Not documented!!!! --->-->cast((cast1 ((Float) (Integer)))): Not documented!!!! --->-->cast(): Missing Description ; compiling file "/var/aw/var/LatexWiki/CAST.NRLIB/CAST.lsp" (written 04 APR 2022 04:54:04 PM):
; /var/aw/var/LatexWiki/CAST.NRLIB/CAST.fasl written ; compilation finished in 0:00:00.009 ------------------------------------------------------------------------ cast is now explicitly exposed in frame initial cast will be automatically loaded when needed from /var/aw/var/LatexWiki/CAST.NRLIB/CAST

This command used to cause a "memory may be damaged" error::

fricas
cast1(1)$CAST
>> System error: The value 1 is not of type CONS.

aldor
#include "axiom"
cast2(i: Integer): Float == {
      j:Float := (i pretend Float)
}
aldor
   Compiling FriCAS source code from file 
      /var/lib/zope2.10/instance/axiom-wiki/var/LatexWiki/casta.as 
      using Aldor compiler and options 
-O -Fasy -Fao -Flsp -lfricas -Mno-ALDOR_W_WillObsolete -DFriCAS -Y $FRICAS/algebra -I $FRICAS/algebra
      Use the system command )set compiler args to change these 
      options.
   The )library system command was not called after compilation.

This command also used cause a "memory may be damaged" error::

fricas
cast2(1)
There are no library operations named cast2 Use HyperDoc Browse or issue )what op cast2 to learn if there is any operation containing " cast2 " in its name.
Cannot find a definition or applicable library operation named cast2 with argument type(s) PositiveInteger
Perhaps you should use "@" to indicate the required return type, or "$" to specify which version of the function you need.