Enum tfm::pl::ast::LigTable

pub enum LigTable {
    Label(SingleValue<LigTableLabel>),
    Lig(PostLigOperation, TupleValue<Char, Char>),
    Kern(TupleValue<Char, Number>),
    Stop(SingleValue<()>),
    Skip(SingleValue<DecimalU8>),
    Comment(String),
}

An element of a LIGTABLE property list.

A lig table property list contains elements of four kinds, specifying a program in a simple command language that TeX uses for ligatures and kerns. If several lig table lists appear, they are effectively concatenated into a single list.

The documentation here and on each variant is based on the documentation in PFtoTF.2014.13.

Variants

Label(SingleValue<LigTableLabel>)

A label specifies that the program for the stated character value starts here. The integer must be the number of a character in the font; its CHARACTER property list must not have a NEXTLARGER or VARCHAR field. At least one LIG or KRN step must follow.

LABEL BOUNDARYCHAR means that the program for beginning-of-word ligatures starts here.

Lig(PostLigOperation, TupleValue<Char, Char>)

The instruction (LIG c r) means, “If the next character is c, then insert character r and possibly delete the current character and/or c; otherwise go on to the next instruction.” Characters r and c must be present in the font.

The LIG keyword may be immediately preceded or followed by a slash, and then immediately followed by > characters not exceeding the number of slashes. Thus there are eight possible forms:

keyword	retain	move to	PostLigOperation value
LIG	neither	inserted	PostLigOperation::RetainNeitherMoveToInserted
/LIG	left	left	PostLigOperation::RetainLeftMoveNowhere
/LIG>	left	inserted	PostLigOperation::RetainLeftMoveToInserted
LIG/	right	inserted	PostLigOperation::RetainRightMoveToInserted
LIG/>	right	right	PostLigOperation::RetainRightMoveToRight
/LIG/	both	left	PostLigOperation::RetainBothMoveToInserted
/LIG/>	both	inserted	PostLigOperation::RetainBothMoveToInserted
/LIG/>>	both	right	PostLigOperation::RetainBothMoveToRight

The slashes specify retention of the left or right original character; the > signs specify passing over the result without further ligature processing.

Kern(TupleValue<Char, Number>)

A kern instruction (KRN c r) means, “If the next character is c, then insert a blank space of width r between the current character and c; otherwise go on to the next instruction.” The value of r, which is in design units, is often negative. Character code c must exist in the font.

Stop(SingleValue<()>)

A stop instruction ends a ligature/kern program. It must follow either a LIG or KRN instruction, not a LABEL or STOP or SKIP.

Skip(SingleValue<DecimalU8>)

A skip instruction specifies continuation of a ligature/kern program after the specified number of LIG or KRN steps has been skipped over. The number of subsequent LIG and KRN instructions must therefore exceed this specified amount.

Comment(String)

A comment that is ignored.

Implementations

impl LigTable

pub const LABEL: &'static str = "LABEL"

pub const LIG_1: &'static str = "LIG"

pub const LIG_2: &'static str = "/LIG"

pub const LIG_3: &'static str = "/LIG>"

pub const LIG_4: &'static str = "LIG/"

pub const LIG_5: &'static str = "LIG/>"

pub const LIG_6: &'static str = "/LIG/"

pub const LIG_7: &'static str = "/LIG/>"

pub const LIG_8: &'static str = "/LIG/>>"

pub const KERN: &'static str = "KRN"

pub const STOP: &'static str = "STOP"

pub const SKIP: &'static str = "SKIP"

pub const ALL_PROPERTY_NAMES: &'static [&'static str] = _

impl LigTable

pub fn lower(self, char_display_format: CharDisplayFormat) -> Node

Trait Implementations

impl<'arbitrary> Arbitrary<'arbitrary> for LigTable

fn arbitrary(u: &mut Unstructured<'arbitrary>) -> Result<Self>

Generate an arbitrary value of Self from the given unstructured data.

fn arbitrary_take_rest(u: Unstructured<'arbitrary>) -> Result<Self>

Generate an arbitrary value of Self from the entirety of the given unstructured data.

fn size_hint(depth: usize) -> (usize, Option<usize>)

Get a size hint for how many bytes out of an Unstructured this type needs to construct itself.

impl Debug for LigTable

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

Formats the value using the given formatter.

impl PartialEq<LigTable> for LigTable

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

This method tests for self and other values to be equal, and is used by ==.

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

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

impl Eq for LigTable

impl StructuralEq for LigTable

impl StructuralPartialEq for LigTable