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Format

WMA link

Format[expr]

used on the left-hand side of an assignment to specify how expr should be printed.

First, we set up a Format definition for f to display its arguments as if it were equivalent to an infix operator "~":

• • Format[f[x___]] := Infix[{x}, "~"]

Now, to see this format in use:

• • f[1, 2, 3]

• • f[1]

Raw objects cannot be formatted:

• • Format[3] = "three";

Format types must be symbols:

• • Format[r, a + b] = "r";

Formats must be attached to the head of an expression:

• • f /: Format[g[f]] = "my f";

Format can be used to specify the request format:

• • Format[Integrate[F[x], x], TeXForm]

Format evaluates its first element before applying the format:

• • Format[Integrate[Cos[x], x], TeXForm]

but the result keeps the structure:

• • % //FullForm

If the second parameter is omitted, Format is ignored:

• • Format[F[x]]

If the second argument is not one of $PrintForms, a message is shown, and the argument is discarded:

• • Format[F[x], NoFormat]

Mathics3 Format output can differ slightly from WMA in what we hope is a more useful way.

Use InputForm if you want to get a Format definition that can be used as Mathics3 input:

• • Format[{a -> Integrate[F[x], x]}, StandardForm] //InputForm

In WMA, you might not get something that can be used as input.

Similarly, use Fullform to get a valid FullForm equivalent expression:

• • Format[{a->Integrate[F[x], x]}, StandardForm] //FullForm