Defining symbol shortcuts in the Front End

Question

I was wondering (because I could not find any documentation on this) if it is possible to do shorthand abbreviations for domains or could one define them?

E.g.

In[1]:= Element[p,Complexes]
Out[1]= p $\in$ Complexes

to instead do something of the following:

In[1]:= p esc elem esc escCC esc
Out[1]= p$\in\mathbb{C}$

And similarly for others:

$ \begin{align} \text{Algebraics}: &\text{esc AA esc} \,\mapsto\mathbb{A} \\ \text{Rationals}: &\text{esc QQ esc} \,\mapsto\mathbb{Q} \\ \text{Booleans}: &\text{esc BB esc} \,\mapsto\mathbb{B} \\ %%\text{Naturals}: &\text{esc NN esc} \,\mapsto\mathbb{N} \\ \text{Integers}: &\text{esc ZZ esc} \,\mapsto\mathbb{Z} \\ \text{Primes}: &\text{esc PP esc} \,\mapsto\mathbb{P} \\ \text{Reals}: &\text{esc RR esc} \,\mapsto\mathbb{R} \\ \end{align} $

Answer 1

Shorthand notations:

All those shorthand notations are well documented.

• For double struck letters like $\mathbb{A}$, use EscdsA, where ds stands for "double struck"

• For script letters like $\mathcal{A}$, use EscscAEsc, where sc stands for — you guessed it — "script".

Creating your own aliases:

To create your own aliases, use InputAliases. I use it to create shortcuts in this answer, and that might give you some ideas. As for a simple example, try the following:

SetOptions[EvaluationNotebook[], InputAliases -> {"AA" -> "\[DoubleStruckCapitalA]"}]

You should now be able to enter $\mathbb{A}$ as desired.

• If you're sequentially adding new rules as you think of them, you can use the following:

  SetOptions[EvaluationNotebook[], InputAliases -> 
      Append[OptionValue[Options[EvaluationNotebook[]], InputAliases], newRule]]
  

  This will append the rules to existing ones for the current notebook.

• To modify an existing rule, use CurrentValue (courtesy Szabolcs):

  CurrentValue[EvaluationNotebook[], {InputAliases, "AA"}] = "\[DoubleStruckCapitalA]"
  

• To set them for all notebooks across all sessions, you can replace EvaluationNotebook[] with $FrontEnd`. This will write it to your front end's `init.m` (located in `$UserBaseDirectory/FrontEnd/init.m). Alternately, you can also enter these directly in the init.m, if you maintain it.

You can create a complete list of rules easily as follows:

rules = # <> # -> ToExpression["\[DoubleStruckCapital" <> # <> "]"]& /@ 
    {"A", "B", "C", "N", "P", "Q", "R", "Z"};

Assigning them to the domains

For your purposes, it is as simple as setting $\mathbb{C}$ equal to Complexes, but note that the Attributes of Complexes won't be copied over.

Answer 2

Perhaps this give the behavior that you desire?

$PreRead = # /. 
    {"\[DoubleStruckCapitalC]" -> Complexes,
     "\[DoubleStruckCapitalA]" -> Algebraics,
     "\[DoubleStruckCapitalQ]" -> Rationals,
     "\[DoubleStruckCapitalB]" -> Booleans,
     "\[DoubleStruckCapitalN]" -> Naturals,
     "\[DoubleStruckCapitalZ]" -> Integers,
     "\[DoubleStruckCapitalP]" -> Primes,
     "\[DoubleStruckCapitalR]" -> Reals} &;

$PrePrint = # /. 
    {Complexes  -> "\[DoubleStruckCapitalC]", 
     Algebraics -> "\[DoubleStruckCapitalA]", 
     Rationals  -> "\[DoubleStruckCapitalQ]", 
     Booleans   -> "\[DoubleStruckCapitalB]", 
     Naturals   -> "\[DoubleStruckCapitalN]", 
     Integers   -> "\[DoubleStruckCapitalZ]", 
     Primes     -> "\[DoubleStruckCapitalP]", 
     Reals      -> "\[DoubleStruckCapitalR]"} &;

Now you can enter these with Escds*Esc where * is the letter, and they will be interpreted as the corresponding domain. Also, the domains will be printed as a double-struck letter.

As noted in the comments Naturals is not a valid Mathematica domain but I kept your notation for consistency.

---

To load these for all sessions on start-up, put this code into one of your init.m files, probably this one: FileNameJoin[{$UserBaseDirectory, "Kernel", "init.m"}].

For custom input aliases add them to the InputAliases list, possibly using the Option Inspector, or with this, but only run it once:

old = Options[$FrontEnd, "InputAliases"][[1, 2]];

new = Join[old,
   {"CC" -> "\[DoubleStruckCapitalC]",
    "AA" -> "\[DoubleStruckCapitalA]",
    "QQ" -> "\[DoubleStruckCapitalQ]",
    "BB" -> "\[DoubleStruckCapitalB]",
    "NN" -> "\[DoubleStruckCapitalN]",
    "ZZ" -> "\[DoubleStruckCapitalZ]",
    "PP" -> "\[DoubleStruckCapitalP]",
    "RR" -> "\[DoubleStruckCapitalR]"}];

SetOptions[$FrontEnd, InputAliases -> new]