Use another language to call a function: Difference between revisions
Use another language to call a function (view source)
Revision as of 18:58, 14 September 2021
, 2 years agoAdded Wren
(Updated to work with Nim 1.4: replaced ".. <text.len" with ".. text.high". Changed compilation command for C.) |
(Added Wren) |
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Line 1,974:
Now the <code>query-cb</code> function generates callbacks that return -1 to the caller, rather than zero, if aborted by a non-local control transfer such as an exception.
=={{header|Wren}}==
Currently, the only way to call a Wren function from another language is to embed it in a program written in that language. Therefore, we embed this Wren script:
<lang ecmascript>/* query.wren */
class RCQuery {
// Both arguments are lists as we need pass by reference here
static query(Data, Length) {
var s = "Here am I"
var sc = s.count
if (sc > Length[0]) return 0 // buffer too small
for (i in 0...sc) Data[i] = s[i].bytes[0]
Length[0] = sc
return 1
}
}</lang>
<br>
in the following C program, compile and run:
<lang c>#include <stdio.h>
#include "wren.h"
char *script;
WrenVM * vm;
WrenForeignMethodFn bindForeignMethod(
WrenVM* vm,
const char* module,
const char* className,
bool isStatic,
const char* signature) {
return NULL; // nothing needed here
}
static void writeFn(WrenVM* vm, const char* text) {
printf("%s", text);
}
void errorFn(WrenVM* vm, WrenErrorType errorType, const char* module, const int line, const char* msg) {
switch (errorType) {
case WREN_ERROR_COMPILE:
printf("[%s line %d] [Error] %s\n", module, line, msg);
break;
case WREN_ERROR_STACK_TRACE:
printf("[%s line %d] in %s\n", module, line, msg);
break;
case WREN_ERROR_RUNTIME:
printf("[Runtime Error] %s\n", msg);
break;
}
}
char *readFile(const char *fileName) {
FILE *f = fopen(fileName, "r");
fseek(f, 0, SEEK_END);
long fsize = ftell(f);
rewind(f);
char *script = malloc(fsize + 1);
fread(script, 1, fsize, f);
fclose(f);
script[fsize] = 0;
return script;
}
int configWrenVM() {
WrenConfiguration config;
wrenInitConfiguration(&config);
config.writeFn = &writeFn;
config.errorFn = &errorFn;
config.bindForeignMethodFn = &bindForeignMethod;
vm = wrenNewVM(&config);
const char* module = "main";
const char* fileName = "query.wren";
script = readFile(fileName);
WrenInterpretResult result = wrenInterpret(vm, module, script);
switch (result) {
case WREN_RESULT_COMPILE_ERROR:
printf("Compile Error!\n");
return -1;
case WREN_RESULT_RUNTIME_ERROR:
printf("Runtime Error!\n");
return -1;
case WREN_RESULT_SUCCESS:
break;
}
return 0;
}
int Query(char *Data, size_t *Length) {
int i, r;
wrenEnsureSlots(vm, 4);
// create list for Data, fill with zeros and put in slot 1
wrenSetSlotNewList(vm, 1);
wrenSetSlotDouble(vm, 2, 0.0);
for (i = 0; i < *Length; ++i) wrenInsertInList(vm, 1, i, 2);
// create list for Length and put in slot 2
wrenSetSlotNewList(vm, 2);
wrenSetSlotDouble(vm, 3, (double)*Length);
wrenInsertInList(vm, 2, 0, 3);
// get handle to Wren's query method
WrenHandle* method = wrenMakeCallHandle(vm, "query(_,_)");
// get its class and put in slot 0
wrenGetVariable(vm, "main", "RCQuery", 0);
// call the Wren method
wrenCall(vm, method);
// get the result and check it's 1
r = (int)wrenGetSlotDouble(vm, 0);
if (r) {
// get the length of the string from slot 2
wrenGetListElement(vm, 2, 0, 3);
*Length = (int)wrenGetSlotDouble(vm, 3);
// copy the bytes from the list in slot 1 to the C buffer
for (i = 0; i < *Length; ++i) {
wrenGetListElement(vm, 1, i, 3);
Data[i] = (char)wrenGetSlotDouble(vm, 3);
}
}
return r;
}
int main() {
int e = configWrenVM();
if (!e) {
char Buffer [1024];
size_t Size = sizeof(Buffer);
if (0 == Query(Buffer, &Size)) {
printf ("failed to call Query\n");
e = 1;
} else {
char * Ptr = Buffer;
while (Size-- > 0) putchar (*Ptr++);
putchar ('\n');
}
}
wrenFreeVM(vm);
free(script);
return e;
}</lang>
{{out}}
<pre>
Here am I
</pre>
=={{header|zkl}}==
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