Enum boxworks::ds::Horizontal

pub enum Horizontal {
    Char(Char),
    HList(HList),
    VList(VList),
    Rule(Rule),
    Mark(Mark),
    Insertion(Insertion),
    Adjust(Adjust),
    Ligature(Ligature),
    Discretionary(Discretionary),
    Whatsit(Box<dyn Whatsit>),
    Math(Math),
    Glue(Glue),
    Kern(Kern),
    Penalty(Penalty),
}

Element of a horizontal list.

Variants

Char(Char)

HList(HList)

VList(VList)

Rule(Rule)

Mark(Mark)

Insertion(Insertion)

Adjust(Adjust)

Ligature(Ligature)

Discretionary(Discretionary)

Whatsit(Box<dyn Whatsit>)

Math(Math)

Glue(Glue)

Kern(Kern)

Penalty(Penalty)

Implementations

impl Horizontal

pub fn precedes_break(&self) -> bool

Whether a glue node that comes after this node may be broken.

For char nodes, this function is essentially undefined in Knuth’s TeX. More specifically, the value depends on the exact character code. In TeX this function is never called for char nodes which is why this is not a problem. Here, we return true for char nodes based on my analysis of all places in Knuth’s TeX where it is invoked:

• TeX.2021.868: precedes_break is called on variable cur_p which is a pointer to a horizontal list. Before this call, the calling code first checks if the node is a character and if so follows the same code path. Thus returning true here is the right thing to do.

• TeX.2021.973: the function is called on a variable prev_p which is a pointer to a vertical list and so the char case never arises.

• TeX.2021.1000: same as the last case.

This function is defined in TeX.2021.148.

pub fn non_discardable(&self) -> bool

Whether this node is discarded after a break.

As with Self::precedes_break, this function is essentially undefined for char nodes in Knuth’s TeX. However there is only one call site (TeX.2021.879) and in that call site char nodes behave as if this function returns true.

This function is defined in TeX.2021.148.

Trait Implementations

impl Debug for Horizontal

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl From<Adjust> for Horizontal

fn from(value: Adjust) -> Self

Converts to this type from the input type.

impl From<Char> for Horizontal

fn from(value: Char) -> Self

Converts to this type from the input type.

impl From<Discretionary> for Horizontal

fn from(value: Discretionary) -> Self

Converts to this type from the input type.

impl From<Glue> for Horizontal

fn from(value: Glue) -> Self

Converts to this type from the input type.

impl From<HList> for Horizontal

fn from(value: HList) -> Self

Converts to this type from the input type.

impl From<Insertion> for Horizontal

fn from(value: Insertion) -> Self

Converts to this type from the input type.

impl From<Kern> for Horizontal

fn from(value: Kern) -> Self

Converts to this type from the input type.

impl From<Ligature> for Horizontal

fn from(value: Ligature) -> Self

Converts to this type from the input type.

impl From<Mark> for Horizontal

fn from(value: Mark) -> Self

Converts to this type from the input type.

impl From<Math> for Horizontal

fn from(value: Math) -> Self

Converts to this type from the input type.

impl From<Penalty> for Horizontal

fn from(value: Penalty) -> Self

Converts to this type from the input type.

impl From<Rule> for Horizontal

fn from(value: Rule) -> Self

Converts to this type from the input type.

impl From<VList> for Horizontal

fn from(value: VList) -> Self

Converts to this type from the input type.

impl PartialEq for Horizontal

fn eq(&self, other: &Self) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Eq for Horizontal