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Description infrastructure for parser based text analysis
Author David Ponce
Maintainer David Ponce

Semantic is an infrastructure for parser based text analysis in Emacs. It is a lexer, parser-generator, and parser. It is written in Emacs Lisp and is customized to the way Emacs thinks about language files, and is optimized to use Emacs' parsing capabilities.

Semantic's goal is to provide an intermediate API for authors of language agnostic tools who want to deal with languages in a generic way. It also provides a simple way for Mode Authors who are experts in their language, to provide a parser for those tool authors, without knowing anything about those tools.

Parser Infrastructure

Lexical Analyzer & Preprocessor

Converts a language into a token stream. Preprocessor support with lexical macro replacement (C/C++).


Converts a lexical token stream into a table of tags defined by the language.

Parser Generator with Bison

David Ponce has ported Bison to Emacs Lisp. New languages can be supported via the wisent parser.

Language Parsers

Parsers that have already been implemented: Emacs Lisp, Java, C/C++, C#, Python, Erlang, awk, Makefile, Scheme, HTML, Texinfo, Javascript, dot. Also: Semantic's own grammar format (.by or .wy)

Incremental parser

Reparses minimal parts of a buffer as you edit.

Idle service manager

Reparses buffers in idle time, and also call other services.

Coding Tools

Semantic supports a wide range of user interface tools.

Smart Completion

Completes symbols actually available in a given context. Some tools call this intellisense.

Speedbar Browser

Code for browsing tag lists with Speedbar.

Documentation Generator

Identifies inline documentation in source code, and can convert it to texinfo. It can also create inline documenation.

Stickyfunc mode

Locks the function declaration you are editing in the header line. (Emacs only).


Create hierarchical imenu menus from parsed files.


Senator is a navigator that permits simple navigation through the parsed language. It also includes token highlighting, and magic cut & paste.

Decoration Modes

Decorate buffers using more than regular expressions, such as overlines for functions, highlight header files Emacs can't find.

Smart Bookmarking

Emacs tracks what you edit, and allows quick navigation by name.

Highlight bad code

text which does not fit the language is underlined.


Draw a chart of some things semantic can quantify.


Examines code, and references those names against a database of pre-parsed files to provide detailed information.

Helpful keybindings

Move to next helm suggestion.
Move to previous helm suggestion.

Common Customization

See Also


Project Pages