semantic is a Haskell library and command line tool for parsing, analyzing, and comparing source code.
In a hurry? Check out our documentation of example uses for the
semantic command line tool.
|Table of Contents|
|Technology and architecture|
semantic --help for complete list of up-to-date options.
Usage: semantic parse ([--sexpression] | [--json] | [--json-graph] | [--symbols] | [--dot] | [--show] | [--quiet]) [FILES...] Generate parse trees for path(s) Available options: --sexpression Output s-expression parse trees (default) --json Output JSON parse trees --json-graph Output JSON adjacency list --symbols Output JSON symbol list --dot Output DOT graph parse trees --show Output using the Show instance (debug only, format subject to change without notice) --quiet Don't produce output, but show timing stats
Usage: semantic diff ([--sexpression] | [--json] | [--json-graph] | [--toc] | [--dot] | [--show]) [FILE_A] [FILE_B] Compute changes between paths Available options: --sexpression Output s-expression diff tree (default) --json Output JSON diff trees --json-graph Output JSON diff trees --toc Output JSON table of contents diff summary --dot Output the diff as a DOT graph --show Output using the Show instance (debug only, format subject to change without notice)
Usage: semantic graph ([--imports] | [--calls]) [--packages] ([--dot] | [--json] | [--show]) ([--root DIR] [--exclude-dir DIR] DIR:LANGUAGE | FILE | --language ARG (FILES... | --stdin)) Compute a graph for a directory or from a top-level entry point module Available options: --imports Compute an import graph (default) --calls Compute a call graph --packages Include a vertex for the package, with edges from it to each module --dot Output in DOT graph format (default) --json Output JSON graph --show Output using the Show instance (debug only, format subject to change without notice) --root DIR Root directory of project. Optional, defaults to entry file/directory. --exclude-dir DIR Exclude a directory (e.g. vendor) --language ARG The language for the analysis. --stdin Read a list of newline-separated paths to analyze from stdin.
|Priority||Language||Parse||Assign||Diff||ToC||Symbols||Import graph||Call graph||Control flow graph|
|Markdown||N/A||N/A||N/A|✅— Supported 🔶— Partial support 🚧— Under development
semantic requires at least GHC 8.6.4 and Cabal 2.4. We strongly recommend using
ghcup to sandbox GHC versions, as GHC packages installed through your OS's package manager may not install statically-linked versions of the GHC boot libraries.
semantic currently builds only on Unix systems; users of other operating systems may wish to use the Docker images.
cabal's Nix-style local builds for development. To get started quickly:
git clone firstname.lastname@example.org:github/semantic.git cd semantic script/bootstrap cabal v2-build cabal v2-test cabal v2-run semantic -- --help
stack as a build tool is not officially supported; there is an unofficial
stack.yaml available, though we cannot make guarantees as to its stability.
Technology and architecture
- Reads blobs.
- Generates parse trees for those blobs with tree-sitter (an incremental parsing system for programming tools).
- Assigns those trees into a generalized representation of syntax.
- Performs analysis, computes diffs, or just returns parse trees.
- Renders output in one of many supported formats.
Semantic leverages a number of interesting algorithms and techniques:
- Myers' algorithm (SES) as described in the paper An O(ND) Difference Algorithm and Its Variations
- RWS as described in the paper RWS-Diff: Flexible and Efficient Change Detection in Hierarchical Data.
- Open unions and data types à la carte.
- An implementation of Abstracting Definitional Interpreters extended to work with an à la carte representation of syntax terms.
Semantic is licensed under the MIT license.