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24.8.1.1 SMIE Setup and Features

SMIE is meant to be a one-stop shop for structural navigation and various other features which rely on the syntactic structure of code, in particular automatic indentation. The main entry point is smie-setup which is a function typically called while setting up a major mode.

Function: smie-setup grammar rules-function &rest keywords​

Setup SMIE navigation and indentation. grammar is a grammar table generated by smie-prec2->grammar. rules-function is a set of indentation rules for use on smie-rules-function. keywords are additional arguments, which can include the following keywords:

  • :forward-token fun: Specify the forward lexer to use.
  • :backward-token fun: Specify the backward lexer to use.

Calling this function is sufficient to make commands such as forward-sexp, backward-sexp, and transpose-sexps be able to properly handle structural elements other than just the paired parentheses already handled by syntax tables. For example, if the provided grammar is precise enough, transpose-sexps can correctly transpose the two arguments of a + operator, taking into account the precedence rules of the language.

Calling smie-setup is also sufficient to make TAB indentation work in the expected way, extends blink-matching-paren to apply to elements like begin...end, and provides some commands that you can bind in the major mode keymap.

Command: smie-close-block​

This command closes the most recently opened (and not yet closed) block.

Command: smie-down-list &optional arg​

This command is like down-list but it also pays attention to nesting of tokens other than parentheses, such as begin...end.