Data commit

Task/Use-another-language-to-call-a-function/Wren/use-another-language-to-call-a-function-1.wren

@@ -0,0 +1,13 @@
+/* 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
+    }
+}

Task/Use-another-language-to-call-a-function/Wren/use-another-language-to-call-a-function-2.wren

@@ -0,0 +1,126 @@
+#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;
+}