Parameters

yex.control.Parameter(value=None, **kwargs)

Bases: yex.control.Unexpandable

Parameters are a specialised form of control, with a value and a type. For example, \hsize holds the width of the current line, which is a dimen.

Like all controls, parameters can be called. This is equivalent to assigning them a value. For example,

    \hsize 3pt

assigns the value 3pt to \hsize.

Each document creates at most one instance of each parameter class.

There is a subclass of Parameter for each type:

• NumberParameter for numbers; TimeParameter is a specialised form for numbers related to the current time.
• DimenParameter for dimens,
• GlueParameter for glue,
• MuglueParameter for muglue, and
• TokenlistParameter for tokenlists.

The parameter classes themselves are subclasses of these.

TeΧbook: pp269-271

Attributes:

Name	Type	Description
our_type	yex.control.register.Type	the class we represent, in the form we use to store it. If this is a tuple, we can contain multiple types; the first one listed will be used to initialise a new control.
initial_value	yex.control.table.Any	the value this parameter has on startup
do_not_initialise	bool	if True, _value will not be initialised. If False (the default), _value will be initialised with a new instance of our_type (or our_type[0] if our_type is a tuple).
is_outer	bool	not applicable, and always False
is_queryable	bool	not applicable, and always True

List of all current parameter subclasses:

Symbol	Type	Class	Description
\abovedisplayshortskip	Glue	Abovedisplayshortskip
\abovedisplayskip	Glue	Abovedisplayskip
\adjdemerits	Number	Adjdemerits
\badness	Number	Badness	How badly the most recent line of text was set.
\baselineskip	Glue	Baselineskip
\belowdisplayshortskip	Glue	Belowdisplayshortskip
\belowdisplayskip	Glue	Belowdisplayskip
\binoppenalty	Number	Binoppenalty
\boxmaxdepth	Dimen	Boxmaxdepth
\brokenpenalty	Number	Brokenpenalty
\clubpenalty	Number	Clubpenalty
\day	Number	Day
\deadcycles	Number	Deadcycles
\defaulthyphenchar	Number	Defaulthyphenchar
\defaultskewchar	Number	Defaultskewchar
\delimiterfactor	Number	Delimiterfactor
\delimitershortfall	Dimen	Delimitershortfall
\displayindent	Dimen	Displayindent
\displaywidowpenalty	Number	Displaywidowpenalty
\displaywidth	Dimen	Displaywidth
\documentfield		DocumentField	A reference to a field in a Document instance.
\doublehyphendemerits	Number	Doublehyphendemerits
\emergencystretch	Dimen	Emergencystretch
\endlinechar	Number	Endlinechar
\errhelp	Tokenlist	Errhelp
\errorcontextlines	Number	Errorcontextlines
\escapechar	Number	Escapechar	The symbol we print before control names.
\everycr	Tokenlist	Everycr
\everydisplay	Tokenlist	Everydisplay
\everyhbox	Tokenlist	Everyhbox
\everyjob	Tokenlist	Everyjob
\everymath	Tokenlist	Everymath
\everypar	Tokenlist	Everypar
\everyvbox	Tokenlist	Everyvbox
\exhyphenpenalty	Number	Exhyphenpenalty
\fam	Number	Fam
\finalhyphendemerits	Number	Finalhyphendemerits
\floatingpenalty	Number	Floatingpenalty
\globaldefs	Number	Globaldefs	Whether definitions should have global effect.
\hangafter	Number	Hangafter
\hangindent	Dimen	Hangindent
\hbadness	Number	Hbadness
\hfuzz	Dimen	Hfuzz
\hoffset	Dimen	Hoffset
\holdinginserts	Number	Holdinginserts
\hsize	Dimen	Hsize	The width of the current line.
\hyphenpenalty	Number	Hyphenpenalty
\inputlineno	Number	Inputlineno	The current line in the input file.
\insertpenalties	Number	Insertpenalties
\interlinepenalty	Number	Interlinepenalty
\jobname	Tokenlist	Jobname
\language	Number	Language
\lastkern	Dimen	Lastkern
\lastpenalty	Number	Lastpenalty
\lastskip	Glue	Lastskip
\lefthyphenmin	Number	Lefthyphenmin
\leftskip	Glue	Leftskip
\linepenalty	Number	Linepenalty
\lineskip	Glue	Lineskip
\lineskiplimit	Dimen	Lineskiplimit
\looseness	Number	Looseness
\mag	Number	Mag
\mathsurround	Dimen	Mathsurround
\maxdeadcycles	Number	Maxdeadcycles
\maxdepth	Dimen	Maxdepth
\medmuskip	Muglue Glue	Medmuskip
\month	Number	Month
\newlinechar	Number	Newlinechar
\nulldelimiterspace	Dimen	Nulldelimiterspace
\output	Tokenlist	Output	Runs every time we have enough text typeset to produce a new page.
\outputpenalty	Number	Outputpenalty
\overfullrule	Dimen	Overfullrule
\pagedepth	Dimen	Pagedepth
\pagefilllstretch	Dimen	Pagefilllstretch
\pagefillstretch	Dimen	Pagefillstretch
\pagefilstretch	Dimen	Pagefilstretch
\pagegoal	Dimen	Pagegoal
\pageshrink	Dimen	Pageshrink
\pagestretch	Dimen	Pagestretch
\pagetotal	Dimen	Pagetotal
\parfillskip	Glue	Parfillskip	The amount of space to add at the end of a paragraph.
\parindent	Dimen	Parindent	The width of the indentation for new paragraphs.
\parskip	Glue	Parskip
\pausing	Number	Pausing
\postdisplaypenalty	Number	Postdisplaypenalty
\predisplaypenalty	Number	Predisplaypenalty
\predisplaysize	Dimen	Predisplaysize
\pretolerance	Number	Pretolerance	How loose lines can get before we try hyphenation.
\prevdepth	Dimen	Prevdepth	The depth of the most recent box, or -1000 for none.
\prevgraf	Number	Prevgraf
\relpenalty	Number	Relpenalty
\righthyphenmin	Number	Righthyphenmin
\rightskip	Glue	Rightskip
\scriptspace	Dimen	Scriptspace
\showboxbreadth	Number	Showboxbreadth
\showboxdepth	Number	Showboxdepth
\spacefactor	Number	Spacefactor
\spaceskip	Glue	Spaceskip
\splitmaxdepth	Dimen	Splitmaxdepth
\splittopskip	Glue	Splittopskip
\tabskip	Glue	Tabskip
\thickmuskip	Muglue Glue	Thickmuskip
\thinmuskip	Muglue Glue	Thinmuskip
\time	Number	Time
\tolerance	Number	Tolerance
\topskip	Glue	Topskip
\tracingcommands	Number	Tracingcommands	Commands before they are executed
\tracinglostchars	Number	Tracinglostchars	Characters not in the font
\tracingmacros	Number	Tracingmacros	Macros, as they are expanded
\tracingonline	Number	Tracingonline	If positive, tracing goes to stdout; otherwise they go to the logfile.
\tracingoutput	Number	Tracingoutput	Boxes that are shipped out
\tracingpages	Number	Tracingpages	Page-break calculations
\tracingparagraphs	Number	Tracingparagraphs	Line-break calculations
\tracingrestores	Number	Tracingrestores	Deassignments when groups end
\tracingstats	Number	Tracingstats	Statistics about memory usage
\uchyph	Number	Uchyph
\vbadness	Number	Vbadness
\vfuzz	Dimen	Vfuzz
\voffset	Dimen	Voffset
\vsize	Dimen	Vsize	The height of a page.
\widowpenalty	Number	Widowpenalty
\xspaceskip	Glue	Xspaceskip
\year	Number	Year
doc['_contents']		X__contents
doc['_created']		X__created	Timestamp of the document's creation. Same as created_at.timestamp().
doc['_font']		X__font
doc['_fonts']		X__fonts
doc['_mode']		X__mode
doc['_modelist']		X__modelist
doc['_output']		X__output
doc['_parshape']		X__parshape

Source code in yex/control/parameter.py

def __init__(self, value=None, **kwargs):

    super().__init__(**kwargs)

    if value is not None:
        self._value = value
    elif self.do_not_initialise:
        pass
    elif isinstance(self.initial_value, self.our_type):
        self._value = self.initial_value
    elif isinstance(self.our_type, tuple):
        self._value = self.our_type[0](self.initial_value)
    else:
        self._value = self.our_type(self.initial_value)

get_the(parser)

Finds a representation of this parameter's value, as used by the control \the.

Returns:

Type	Description
str	a string representing the value.

Source code in yex/control/parameter.py

def get_the(self, parser: 'yex.parse.Parser') -> str:
    r"""
    Finds a representation of this parameter's value, as used by
    the control \the.

    Returns:
        a string representing the value.
    """
    if isinstance(self.value, str):
        return self.value
    else:
        return repr(self.value)

set_from(parser)

Sets the value from a token stream.

Source code in yex/control/parameter.py

def set_from(self, parser: 'yex.parse.Parser'):
    """
    Sets the value from a token stream.
    """
    parser.eat_optional_char('=')
    v = self.our_type.from_parser(parser)
    logger.debug("Setting %s=%s",
            self, v)
    self.value = v