Elisp: Syntax Table

What is Syntax Table

Syntax Table is a lookup table. It classify each character into a class, for all unicode characters.

Classes are: letters, punctuations, brackets, programing language identifiers, comment character, string delimiters, etc.

Each Buffer Has Its Own Value of Syntax Table

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

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〕

Summary of Syntax Table

• Syntax table is a lookup table. It group characters into classes, such as whitespace, word, symbol (programing language identifier), punctuations, bracket, etc. 〔see Elisp: Syntax Class〕
• To create a syntax table, use make-syntax-table and others. 〔see Elisp: Create Syntax Table〕
• Each buffer has its own syntax table. (it's like Buffer Local Variable, but there is no variable.)
• Use set-syntax-table to set a syntax table for current buffer.