haskell-names: Name resolution library for Haskell

[ bsd3, language, library ] [ Propose Tags ]

This package takes modules parsed with `haskell-src-exts`, resolves used names and annotates the parsed module with scoping information.

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Versions [RSS] [faq] 0.1, 0.1.1, 0.1.2, 0.2, 0.2.1, 0.3, 0.3.1, 0.3.2,,,,,,,,, 0.3.3,,, 0.4, 0.4.1, 0.5.0, 0.5.1, 0.5.2, 0.5.3, 0.6.0, 0.7.0, 0.8.0, 0.9.0, 0.9.1, 0.9.2, 0.9.3, 0.9.4, 0.9.5, 0.9.6, 0.9.7, 0.9.8, 0.9.9
Change log CHANGELOG.md
Dependencies aeson (>= && <1.6), base (==4.*), bytestring (>= && <0.11), containers (>=0.2 && <0.7), data-lens-light (>= && <0.2), filepath (>=1.1 && <1.5), haskell-src-exts (>=1.21 && <1.24), mtl (>=2.2.1 && <2.3), tagged (>=0.8.4 && <0.9), transformers (>= && <0.6), traverse-with-class (>= && <1.1), uniplate (>=1.5.1 && <1.7) [details]
License BSD-3-Clause
Author Philipp Schuster, Roman Cheplyaka, Lennart Augustsson
Maintainer Philipp Schuster
Category Language
Home page http://documentup.com/haskell-suite/haskell-names
Source repo head: git clone git://github.com/haskell-suite/haskell-names.git
Uploaded by AlexandrRuchkin at 2020-05-26T21:56:06Z
Distributions LTSHaskell:0.9.9, NixOS:0.9.9, Stackage:0.9.9
Downloads 34878 total (146 in the last 30 days)
Rating 2.25 (votes: 2) [estimated by Bayesian average]
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Status Hackage Matrix CI
Docs available [build log]
Last success reported on 2020-05-27 [all 1 reports]


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For package maintainers and hackage trustees


Readme for haskell-names-0.9.9

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haskell-names Build Status

haskell-names does name and module resolution for haskell-src-exts AST.

Namely, it can do the following:

  • For a list of modules, compute the list of symbols each module exports. This is called resolve.
  • For each name in a module, figure out what it refers to — whether it's bound locally (say, by a where clause) or globally (and then give its origin). This is called annotate.


If you're building a development version, then you might also need to install a development version of haskell-src-exts.


An environment is a map from module name to list of symbols the module exports. Symbols are for example types, classes, functions etc. We persist these lists in a JSON format. For example, here are a couple of entries from Prelude.names:

    "name": "map",
    "entity": "value",
    "module": "GHC.Base"
    "name": "IO",
    "entity": "newtype",
    "module": "GHC.Types"

As you see, each entity is annotated with the module where it was originally defined. Additionally, class methods, field selectors, and data constructors are annotated with the class or type they belong to.

haskell-names provides functions readSymbols and writeSymbols to read and write interface files.

Name resolution

The annotate function annotates the given module with scoping information.

Its essence is described in the article Open your name resolution.


The example in examples/HeadUsage.hs shows how you would find out if a Haskell modules given on stdin uses Prelude.head.

% cabal exec -- runghc examples/HeadUsages.hs
one = head [1]
Prelude.head is used at stdin: (1:7) - (1:11)

% cabal exec -- runghc examples/HeadUsages.hs
import Prelude hiding (head)
import Data.Text

f = head (pack "foo")
Congratulations! Your code doesn't use Prelude.head

The example in examples/ModuleExports.hs shows how the resolve function behaves. It expects to find examples/moduleexports.Example.hs and examples/moduleexports/Example/Internal.hs.

% cabal exec -- runghc examples/ModuleExports.hs
Only example: fromList [(ModuleName () "Example",[])]
Only internal: fromList [(ModuleName () "Example.Internal",[Value {symbolModule = ModuleName () "Example.Internal", symbolName = Ident () "details"}])]
Example & Internal: fromList [(ModuleName () "Example",[Value {symbolModule = ModuleName () "Example.Internal", symbolName = Ident () "details"}]),(ModuleName () "Example.Internal",[Value {symbolModule = ModuleName () "Example.Internal", symbolName = Ident () "details"}])]
Internal & Example: fromList [(ModuleName () "Example",[Value {symbolModule = ModuleName () "Example.Internal", symbolName = Ident () "details"}]),(ModuleName () "Example.Internal",[Value {symbolModule = ModuleName () "Example.Internal", symbolName = Ident () "details"}])]
Example after Internal: fromList [(ModuleName () "Example",[Value {symbolModule = ModuleName () "Example.Internal", symbolName = Ident () "details"}]),(ModuleName () "Example.Internal",[Value {symbolModule = ModuleName () "Example.Internal", symbolName = Ident () "details"}])]
Internal after Example: fromList [(ModuleName () "Example",[]),(ModuleName () "Example.Internal",[Value {symbolModule = ModuleName () "Example.Internal", symbolName = Ident () "details"}])]

API documentation

The core module you need is Language.Haskell.Names

Other modules are more experimental, less documented, and you probably don't need them anyway.

Known issues

See the list of all issues.

  • haskell-names doesn't perform validation yet. If a module is not valid Haskell, then the behaviour is undefined. See the issues marked as validation.
  • Symbol fixities are not recorded (#1)
  • Type variables are not resolved (#2)
  • Arrows are not fully supported (#8)


Philipp Schuster is the primary maintainer.

Adam Bergmark is the backup maintainer. Please get in touch with him if the primary maintainer cannot be reached.