[EvaluationInstruction::] The Evaluation Construct.

Defining the Evaluation construct.

@

=
void EvaluationInstruction::define_construct(void) {
	inter_construct *IC = InterInstruction::create_construct(EVALUATION_IST, I"evaluation");
	InterInstruction::specify_syntax(IC, I"evaluation");
	InterInstruction::fix_instruction_length_between(IC, EXTENT_EVAL_IFR, EXTENT_EVAL_IFR);
	InterInstruction::allow_in_depth_range(IC, 1, INFINITELY_DEEP);
	InterInstruction::permit(IC, INSIDE_CODE_PACKAGE_ICUP);
	InterInstruction::permit(IC, CAN_HAVE_CHILDREN_ICUP);
	METHOD_ADD(IC, CONSTRUCT_READ_MTID, EvaluationInstruction::read);
	METHOD_ADD(IC, CONSTRUCT_WRITE_MTID, EvaluationInstruction::write);
	METHOD_ADD(IC, CONSTRUCT_VERIFY_CHILDREN_MTID, EvaluationInstruction::verify_children);
}

@

@d BLOCK_EVAL_IFLD 2

@d EXTENT_EVAL_IFR 3

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void EvaluationInstruction::read(inter_construct *IC, inter_bookmark *IBM, inter_line_parse *ilp, inter_error_location *eloc, inter_error_message **E) {
	inter_package *routine = InterBookmark::package(IBM);
	if (routine == NULL) { *E = InterErrors::plain(I"'evaluation' used outside function", eloc); return; }

	*E = EvaluationInstruction::new(IBM, ilp->indent_level, eloc);
}

inter_error_message *EvaluationInstruction::new(inter_bookmark *IBM, int level, inter_error_location *eloc) {
	inter_tree_node *P = Inode::new_with_1_data_field(IBM, EVALUATION_IST, 0, eloc, (inter_ti) level);
	inter_error_message *E = VerifyingInter::instruction(InterBookmark::package(IBM), P); if (E) return E;
	NodePlacement::move_to_moving_bookmark(P, IBM);
	return NULL;
}

void EvaluationInstruction::write(inter_construct *IC, OUTPUT_STREAM, inter_tree_node *P, inter_error_message **E) {
	WRITE("evaluation");
}

void EvaluationInstruction::verify_children(inter_construct *IC, inter_tree_node *P, inter_error_message **E) {
	LOOP_THROUGH_INTER_CHILDREN(C, P) {
		if ((C->W.instruction[0] != INV_IST) && (C->W.instruction[0] != SPLAT_IST) && (C->W.instruction[0] != VAL_IST) && (C->W.instruction[0] != LABEL_IST) && (C->W.instruction[0] != EVALUATION_IST)) {
			*E = Inode::error(C, I"only an inv, a splat, a val, or a label can be below an evaluation", NULL);
			return;
		}
	}
}