Wolfram: Source Code Encoding and Unicode

Wolfram Source Code is ASCII Only

Wolfram source code and the notebook, is saved in ASCII character set only.

• ASCII Characters
• Wolfram Language File Encoding

Wolfram Supports Unicode Characters

Wolfram supports Unicode characters. e.g. → α 水 😃

Syntax of Unicode Characters

Unicode characters are represented in source code in one of the following syntax.

\[Name]

Named character syntax. e.g. \[Alpha] for α (U+3B1: GREEK SMALL LETTER ALPHA)

there are about 1k named characters.

\:hhhh

Lowercase 4 hexadecimal digits character syntax. e.g. \:6c34 for 水 (U+6C34: CJK IDEOGRAPH-6C34)

\|hhhhhh

Lowercase 6 hexadecimal digits character syntax. e.g. \|01f603 for 😃 (U+1F603: SMILING FACE WITH OPEN MOUTH)

What is Named Character

• Named character is a set of characters that have the syntax \[Name]
• Named characters is a special character set designed by Wolfram, to represent math symbols or other icons.
• As of 2025-03-01, there are 1061 named chars.
• Most of the name characters are also in Unicode, but not all.

• When you type a named char syntax, it is displayed as the character glyph. e.g. \[Alpha] is shown as α.

ListingOfNamedCharacters

Some Named Characters Are Not in Unicode

Some of the named chars are not in Unicode. For example:

Some Unicode Math Symbols Are Not in Named Chars

• Chinese chars, Arabic alphabets etc, are not part of Wolfram named chars.
• Many math or tech symbols in Unicode are not in Wolfram named characters.

(Wolfram has only over 1k named characters. Unicode has over 140k characters.)

Example of Unicode Characters that Are Not in Wolfram Named Characters

• ⫷ (U+2AF7: TRIPLE NESTED LESS-THAN)
• ⫸ (U+2AF8: TRIPLE NESTED GREATER-THAN)
• 🤡 (U+1F921: CLOWN FACE)
• 水 (U+6C34: CJK IDEOGRAPH-6C34)

Which Unicode Character Are Mapped to Wolfram Named Character

when you paste in unicode text to Wolfram Notebook , some characters are mapped to Wolfram named characters.

• π (U+3C0: GREEK SMALL LETTER PI) maps to \[Pi]

However, some unicode char such as ℝ (U+211D: DOUBLE-STRUCK CAPITAL R) does not map to the similar named char \[DoubleStruckCapitalR]

Am not aware of a document that list all the named characters and the unicode they map to.

Interpretation of Unicode Characters

When you paste in a unicode character, how does Wolfram Language interpret it?

If Not Mapped to a Named Character

If the character does not map to one of the named character, it is treated like any letter, such as a b c. You can use it in variable name or function name. For example:

Table[♥ , {♥, 1, 5}]

(* {1, 2, 3, 4, 5} *)

Type of Named Chars: Letter or Letter-Like Forms, vs Operator

A named character is one of two types:

• letter or letter-like forms
• operator

Each character in these class may or may not have builtin meaning.

Here's a tree illustration:

• named char
  • letter or letter-like
    • has builtin meaning (e.g. π ° ∞)
    • no builtin meaning. (e.g. α)
  • operator
    • has builtin meaning (e.g. ≥ √ ∑ ∫)
    • no builtin meaning. (e.g. ± ⊕)
• not named char (e.g. 🤡 💯)

Letter and Letter-Like-Form, vs Operator

If it's letter or letter-like forms, either it has a builtin meaning, e.g. ° same as Degree, π same as Pi, ∞ same as Infinity, or it is treated as any letter, such as λ. It is treated the same as any of a, b, c etc. You can use it as part of variable/function name.

If it's a operator, either it has a builtin meaning, such as √ ≥ ∑ ∫ Or it does not have builtin meaning, such as ⊕ .

Operator Characters

Operator characters have builtin syntactic meaning, i.e. unary or binary operator, and operator precedence.

A named character many have special meaning in Wolfram Language. For example, π \[Pi] is automatically considered identical to the built-in symbol Pi, which means the mathematical constant. (So, if you type \[Pi] or \:03c0, they are displayed as π with meaning of Pi.). Here's some examples of special meaning named chars.

• Reference
• https://reference.wolfram.com/language/ref/MakeExpression.html
• https://reference.wolfram.com/language/tutorial/MathematicalAndOtherNotation.html#41

keyboard Shortcut Alias for Named Chars

A named character may have one or more aliases for ease of input. For example, to enter α, you can type EscaEsc or EscalphaEsc. Here's some examples:

• https://reference.wolfram.com/language/tutorial/InputAndOutputInNotebooks.html#4718
• https://reference.wolfram.com/language/guide/SpecialCharacters.html

Inputting Special Chars

You can input a special character by:

• Use one of the graphical palettes.
• Press Esc, then the char's alias name, then Esc again.
• Copy the Unicode char somewhere and pasting it in Wolfram Notebook.
• Type it like this: \[Name].
• Type the Unicode hexadecimal like this: \:xxxx or \|xxxxxx