Programmer Reference : VAST Virtual Machine API : Sample user primitives for VAST
Sample user primitives for VAST
User primitives are stored in shared libraries. A shared library called sample exists in the samples\primitiv directory. (For example, for Microsoft Windows, the primitiv subdirectory contains sample.dll.) The name of the sample library must be specified in the Smalltalk primitive declarations.
sample.c contains (at least) the following:
#include "esuser.h"
#include <string.h>
I_32 i1;
I_32 i2;
U_32 rc;
EsObject retVal;
rc = EsIntegerToI32(EsPrimArgument(1), &i1);
if (rc != EsPrimErrNoError)
EsPrimFail(rc, 1);
rc = EsIntegerToI32(EsPrimArgument(2), &i2);
if (rc != EsPrimErrNoError)
EsPrimFail(rc, 2);
rc = EsI32ToInteger(i1 + i2, &retval);
if (rc != EsPrimErrNoError)
EsPrimFail(rc, EsPrimArgNumNoArg);
EsObject result;
U_32 rc;
rc = EsCStringToString("This is a C string", &result);
if (rc != EsPrimErrNoError)
EsPrimFail(rc, EsPrimArgNumNoArg);
EsPrimitiveTableEntry("add2Numbers", add2Numbers)
EsPrimitiveTableEntry("exampleMakeAString", exampleMakeAString)
In Smalltalk, add the following methods to UndefinedObject:
add: a and: b
<primitive: 'sample':add2Numbers>
^self primitiveFailed
<primitive: 'sample':exampleMakeAString>
^self primitiveFailed
Now evaluate the following in a workspace (the expected result follows the --->):
nil add: 54 and: 7 ---> 61
nil add: 16r7FFFFFFF and: 1 ---> -2147483648 (overflow)
nil add: -1 and: -2 ---> -3
nil add: 1073741823 and: 1 ---> 1073741824 (LargeInteger)
nil add: $a and: 2 ---> walkback "invalid class in argument 1"
nil add: 0 and: 16r100000000 ---> walkback "value out of range in argument 2"
nil makeAString ---> 'This is a C string'
Last modified date: 02/21/2021