---
name: "LaTeXML::Core::Stomach"
section: "3pm"
platform: "linux"
package: "latexml"
version: "0.8.8-2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/LaTeXML::Core::Stomach"
---

# LaTeXML::Core::Stomach(3pm)

digests tokens into boxes, lists, etc.

## NAME

"LaTeXML::Core::Stomach" - digests tokens into boxes, lists, etc.

## DESCRIPTION

`"LaTeXML::Core::Stomach"` digests tokens read from a LaTeXML::Core::Gullet (they will have already been expanded).

It extends LaTeXML::Common::Object.

There are basically four cases when digesting a LaTeXML::Core::Token:

- A plain character

  is simply converted to a LaTeXML::Core::Box recording the current LaTeXML::Common::Font.

- A primitive

  If a control sequence represents LaTeXML::Core::Definition::Primitive, the primitive is invoked, executing its stored subroutine.  This is typically done for side effect (changing the state in the LaTeXML::Core::State), although they may also contribute digested material. As with macros, any arguments to the primitive are read from the LaTeXML::Core::Gullet.

- Grouping (or environment bodies)

  are collected into a LaTeXML::Core::List.

- Constructors

  A special class of control sequence, called a LaTeXML::Core::Definition::Constructor produces a LaTeXML::Core::Whatsit which remembers the control sequence and arguments that created it, and defines its own translation into `"XML"` elements, attributes and data. Arguments to a constructor are read from the gullet and also digested.

### Digestion

- "$list = $stomach-\>digestNextBody;"

  Return the digested LaTeXML::Core::List after reading and digesting a \`body' from the its Gullet.  The body extends until the current level of boxing or environment is closed.

- "$list = $stomach-\>digest($tokens);"

  Return the LaTeXML::Core::List resuting from digesting the given tokens. This is typically used to digest arguments to primitives or constructors.

- "@boxes = $stomach-\>invokeToken($token);"

  Invoke the given (expanded) token.  If it corresponds to a Primitive or Constructor, the definition will be invoked, reading any needed arguments fromt he current input source. Otherwise, the token will be digested. A List of Box's, Lists, Whatsit's is returned.

- "@boxes = $stomach-\>regurgitate;"

  Removes and returns a list of the boxes already digested at the current level.  This peculiar beast is used by things like \\choose (which is a Primitive in TeX, but a Constructor in LaTeXML).

### Grouping

- "$stomach-\>bgroup;"

  Begin a new level of binding by pushing a new stack frame, and a new level of boxing the digested output.

- "$stomach-\>egroup;"

  End a level of binding by popping the last stack frame, undoing whatever bindings appeared there, and also decrementing the level of boxing.

- "$stomach-\>begingroup;"

  Begin a new level of binding by pushing a new stack frame.

- "$stomach-\>endgroup;"

  End a level of binding by popping the last stack frame, undoing whatever bindings appeared there.

### Modes

- "$stomach-\>beginMode($mode);"

  Begin processing in `$mode`; one of 'text', 'display-math' or 'inline-math'. This also begins a new level of grouping and switches to a font appropriate for the mode.

- "$stomach-\>endMode($mode);"

  End processing in `$mode`; an error is signalled if `$stomach` is not currently in `$mode`.  This also ends a level of grouping.

## AUTHOR

Bruce Miller \<bruce.miller@nist.gov\>

## COPYRIGHT

Public domain software, produced as part of work done by the United States Government & not subject to copyright in the US.