Options for Expression Input and Output

Options associated with the interactive entering of expressions.

The option (RefLink[SingleLetterItalics, paclet:ref/SingleLetterItalics]) is typically set whenever a cell uses (RefLink[TraditionalForm, paclet:ref/TraditionalForm]).

Here is an expression entered with default options for a (RefLink[StandardForm, paclet:ref/StandardForm]) input cell.

Here is the same expression entered in a cell with (RefLink[SingleLetterItalics, paclet:ref/SingleLetterItalics])->True and (RefLink[ZeroWidthTimes, paclet:ref/ZeroWidthTimes])->True.

Built into the Wolfram Language are a large number of aliases for common special characters. (RefLink[InputAliases, paclet:ref/InputAliases]) allows you to add your own aliases for further special characters or for any other kind of Wolfram Language input. A rule of the form "name"->expr specifies that name should immediately be replaced on input by expr.

Aliases are delimited by explicit Esc characters. The option (RefLink[InputAutoReplacements, paclet:ref/InputAutoReplacements]) allows you to specify that certain kinds of input sequences should be immediately replaced even when they have no explicit delimiters. By default, for example, -> is immediately replaced by ->. You can give a rule of the form "seq"->"rhs" to specify that whenever seq appears as a token in your input, it should immediately be replaced by rhs.

Settings for (RefLink[LanguageCategory, paclet:ref/LanguageCategory]) to control spell checking and hyphenation.

The option (RefLink[LanguageCategory, paclet:ref/LanguageCategory]) allows you to tell the Wolfram Language what type of contents it should assume cells have. This determines how spelling and structure should be checked, and how hyphenation should be done.

Options associated with interactive manipulation of expressions.

The Wolfram Language normally allows you to select any part of an expression that you see on the screen. Occasionally, however, you may find it useful to get the Wolfram Language to allow only selections which correspond to complete subexpressions. You can do this by setting the option (RefLink[StructuredSelection, paclet:ref/StructuredSelection])->(RefLink[True, paclet:ref/True]).

Here is an expression with a piece selected.

With (RefLink[StructuredSelection, paclet:ref/StructuredSelection])->(RefLink[True, paclet:ref/True]) only complete subexpressions can ever be selected.

Unlike most of the other options here, the (RefLink[DragAndDrop, paclet:ref/DragAndDrop]) option can only be set for the entire front end, rather than for individual cells or cell styles.

Examples of specifying options for the display of expressions.

As discussed in "Textual Input and Output", the Wolfram Language provides many options for specifying how expressions should be displayed. By using (RefLink[StyleBox, paclet:ref/StyleBox])[boxes,opts] you can apply such options to collections of boxes. But the Wolfram Language is set up so that any option that you can give to a (RefLink[StyleBox, paclet:ref/StyleBox]) can also be given to a complete (RefLink[Cell, paclet:ref/Cell]) object, or even a complete (RefLink[Notebook, paclet:ref/Notebook]). Thus, for example, options like (RefLink[Background, paclet:ref/Background]) and (RefLink[LineIndent, paclet:ref/LineIndent]) can be given to complete cells as well as to individual (RefLink[StyleBox, paclet:ref/StyleBox]) objects.

There are some options that apply only to a particular type of box, such as (RefLink[GridBox, paclet:ref/GridBox]). Usually these options are best given separately in each (RefLink[GridBox, paclet:ref/GridBox]) where they are needed. But sometimes you may want to specify default settings to be inherited by all (RefLink[GridBox, paclet:ref/GridBox]) objects that appear in a particular cell. You can do this by giving these default settings as the value of the option GridBoxOptions for the whole cell.

For most box types named XXXBox, the Wolfram Language provides a cell option XXXBoxOptions that allows you to specify the default options settings for that type of box. Box types which take options can also have their options set in a stylesheet by defining the XXX style. The stylesheets which come with the Wolfram System define many such styles.