Function AR_REDUCE

src/arithmetic/list_funcs/list_funcs.c:696–749

}

SIValue AR_REDUCE
(
	SIValue *argv,
	int argc,
	void *private_data
) {
	// reduce(sum = 0, n IN [1,2,3] | sum + n)
	// argv[0] - accumulator initial value
	// argv[1] - array
	// argv[2] - input record

	// return NULL if expected array is NULL
	if(SI_TYPE(argv[1]) == T_NULL) return SI_NullVal();

	// set arguments
	SIValue        accum  =  SI_ShareValue(argv[0]);
	SIValue        list   =  argv[1];
	Record         rec    =  argv[2].ptrval;
	ListReduceCtx  *ctx   =  private_data;

	// on first invocation build the internal record
	if(ctx->record == NULL) _PopulateReduceCtx(ctx, rec);
	Record r = ctx->record;

	// populate record with the contents of the input record
	Record_Clone(rec, r);

	// init accumulator within internal record
	Record_AddScalar(r, ctx->accumulator_idx, accum);

	// evaluate expression for each list element
	// e.g. for `n` in `list`, compute: sum = sum + n
	uint len = SIArray_Length(list);
	for(uint i = 0; i < len; i++) {
		// retrieve the current element
		SIValue elem = SIArray_Get(list, i);

		// set current element to the record
		Record_AddScalar(r, ctx->variable_idx, elem);
		// compute sum = sum + i
		SIValue new_accum = AR_EXP_Evaluate_NoThrow(ctx->exp, r);
		SIValue_Free(accum);
		accum = new_accum;
		// update accumulator within internal record
		Record_AddScalar(r, ctx->accumulator_idx, accum);
	}

	// clear internal record
	Record_Remove(r, ctx->variable_idx);
	Record_Remove(r, ctx->accumulator_idx);

	SIValue_Persist(&accum);
	return accum;
}

void Register_ListFuncs() {
	SIType *types;