Elisp: Syntax Table

What is Syntax Table

Syntax table is a lookup table. It store info about character's purpose, such as whitespace, word, symbol (programing language identifier), punctuations, bracket, etc. 〔see Elisp: Syntax Class〕

Where is Syntax Table Used

Syntax table is heavily used in emacs. For example,

• Most cursor movement commands rely on syntax table. For example, when you forward-word 【Alt+f】, emacs moves cursor until it reaches a character that's not in the “word” class.
• Syntax coloring of strings and comments rely on syntax table. 〔see Elisp: Syntax Color Comments〕
• Lisp mode's parenthesis navigation depends on syntax table. 〔see Emacs: Navigate Lisp Code as Tree〕

Syntax Table is Local to Buffer

Each buffer has its own syntax table. (it's like Buffer Local Variable, but there is no variable.)

Typically, when a Major Mode is activated, it changes the current buffer's syntax table.

Standard Syntax Table

• Standard syntax table is the syntax table used by Fundamental Mode
• Every syntax table is derived from standard syntax table.

The function standard-syntax-table returns the standard syntax table.

Syntax Table Inheritance

Emacs syntax table has inheritance. That is, each syntax table you create inherits a parent syntax table. You do not need to set every character's syntax class. When a syntax table does not have entry for a character, it uses the parent table.

Syntax table commands have optional parameter for a table name of a parent table. When not specified, the parent syntax table is the standard syntax table.

• Syntax Table Functions (ELISP Manual)

Create a Syntax Table

• Elisp: Create Syntax Table

Reference

• Syntax Tables (ELISP Manual)