From f9d905b324e527528c4377a3757d2a39a585ed93 Mon Sep 17 00:00:00 2001 From: Axel Huebl Date: Wed, 29 Oct 2025 09:43:28 -0700 Subject: [PATCH 1/2] `Empty` Element The empty element, contrary to the `Marker`, is a truly empty, thin element that does nothing. It can be used for bookkeeping, e.g., as the empty result of a search or as an indicator for an invalid element. For all other purposes, use `Marker`. Renamed from `Null` because `Null`/`null`/`None`/`none` are reserved keywords in the file formats and programming languages we support in PALS. --- source/element-kinds.md | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/source/element-kinds.md b/source/element-kinds.md index abc010d..ac0207a 100644 --- a/source/element-kinds.md +++ b/source/element-kinds.md @@ -386,8 +386,8 @@ Element parameter groups associated with this element kind are: - [**TrackingP**](#s:tracking.params): Tracking parameters. %--------------------------------------------------------------------------------------------------- -(s:nullele)= -## NullEle Element +(s:empy)= +## Empty Element Placeholder element used for bookkeeping when constructing the expanded lattice. This element is empty, zero length and does nothing. @@ -395,9 +395,9 @@ This element can be used as a [`base_item`](#s:placement) element for [superposi Additionally, this element can be used, for example, to denote an invalid element in the internal structures defined by a program. -`NullEle` elements present in a lattice file will, as a part of lattice expansion, be removed. -That is, `NullEle` elements will never be present in the final expanded lattice and -tracking through a `NullEle` will never be needed. +`Empty` elements present in a lattice file will, as a part of lattice expansion, be removed. +That is, `Empty` elements will never be present in the final expanded lattice and +tracking through a `Empty` will never be needed. This element does not have any associated parameter groups. From 968a1e964f2d0b1aae284b208f29a4be46605ccf Mon Sep 17 00:00:00 2001 From: Axel Huebl Date: Tue, 11 Nov 2025 13:38:44 -0800 Subject: [PATCH 2/2] Name: `Placeholder` --- source/element-kinds.md | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/source/element-kinds.md b/source/element-kinds.md index ac0207a..26c69db 100644 --- a/source/element-kinds.md +++ b/source/element-kinds.md @@ -386,18 +386,18 @@ Element parameter groups associated with this element kind are: - [**TrackingP**](#s:tracking.params): Tracking parameters. %--------------------------------------------------------------------------------------------------- -(s:empy)= -## Empty Element +(s:placeholder)= +## Placeholder Element Placeholder element used for bookkeeping when constructing the expanded lattice. -This element is empty, zero length and does nothing. +This element has zero length and does nothing. This element can be used as a [`base_item`](#s:placement) element for [superpositions](#s:superposition). Additionally, this element can be used, for example, to denote an invalid element in the internal structures defined by a program. -`Empty` elements present in a lattice file will, as a part of lattice expansion, be removed. -That is, `Empty` elements will never be present in the final expanded lattice and -tracking through a `Empty` will never be needed. +`Placeholder` elements present in a lattice file will, as a part of lattice expansion, be removed. +That is, `Placeholder` elements will never be present in the final expanded lattice and +tracking through a `Placeholder` will never be needed. This element does not have any associated parameter groups.