expr 0.0.0

  • README.md
  • Installing
  • Versions
  • 43

Travis Codecov

Expr library

This library is aimed at replacing the use of eqlib in QEDb. The design goals are as follows:

  • Design easier expression data structure (array instead of tree).
  • Adopt expression parsing and LaTeX printing code from eqlib.
  • Create codecs that are compatible with the array and binary codec from eqlib.
  • Avoid the use of a Subs class as much as possible using plain functions.
  • Add more flexible manipulation and comparison methods that are targeted at the use cases of QEDb.

The reason to reimplement this part of the QEDb project from scratch is to ensure high code quality and avoid the accumulation of obscure features. When eqlib was designed many of the current design choices of QEDb were still unknown.


The library has three parts: the core functions, the interface functions, and the lemma functions. The core functions focus only on expression manipulation in general and do not implement any higher level system. The interface functions contain the expression parser, text generator (printer), and binary codec. The lemma functions implement a higher level system for building proofs (lemmas) using the algorithms implemented in this library.


Some entity names have changed with respect to eqlib in order to improve readability:

  • Generic functions are now called patterns
  • Substitutions are now called transforms
  • Rules are now called formulas
  • Steps are now called rewrites
  • Proofs are now called lemmas

Use this package as a library

1. Depend on it

Add this to your package's pubspec.yaml file:

  expr: "^0.0.0"

2. Install it

You can install packages from the command line:

with pub:

$ pub get

with Flutter:

$ flutter packages get

Alternatively, your editor might support pub get or flutter packages get. Check the docs for your editor to learn more.

3. Import it

Now in your Dart code, you can use:

      import 'package:expr/expr.dart';
Version Uploaded Documentation Archive
0.0.0 Dec 15, 2017 Go to the documentation of expr 0.0.0 Download expr 0.0.0 archive


We analyzed this package on Jun 19, 2018, and provided a score, details, and suggestions below. Analysis was completed with status completed using:

  • Dart: 2.0.0-dev.63.0
  • pana: 0.11.3


Describes how popular the package is relative to other packages. [more]
0 / 100
Code health derived from static analysis. [more]
98 / 100
Reflects how tidy and up-to-date the package is. [more]
70 / 100
Overall score:
Weighted score of the above. [more]
Learn more about scoring.


Detected platforms: Flutter, web, other

No platform restriction found in primary library package:expr/expr.dart.


  • Maintain CHANGELOG.md.

    Changelog entries help clients to follow the progress in your code.

  • Homepage does not exists.

    We were unable to access https://github.com/qedb/expr at the time of the analysis.

  • Fix analysis and formatting issues.

    Analysis or formatting checks reported 3 errors.

    Strong-mode analysis of lib/src/core/expr.dart failed with the following error:

    line: 9 col: 7
    Missing concrete implementations of 'Iterable.followedBy', 'Iterable.whereType', 'List.+', 'List.cast' and 4 more.

    Strong-mode analysis of lib/src/core/mapping.dart failed with the following error:

    line: 8 col: 7
    Missing concrete implementations of 'Map.addEntries', 'Map.cast', 'Map.map', 'Map.removeWhere' and 3 more.

  • The description is too short.

    Add more detail about the package, what it does and what is its target use case. Try to write at least 60 characters.

  • Package is pre-v1 release.

    While there is nothing inherently wrong with versions of 0.*.*, it usually means that the author is still experimenting with the general direction API.

  • Maintain an example.

    Create a short demo in the example/ directory to show how to use this package. Common file name patterns include: main.dart, example.dart or you could also use expr.dart.


Package Constraint Resolved Available
Direct dependencies
Dart SDK >=1.8.0 <2.0.0
collection ^1.14.3 1.14.10
quiver ^0.25.0 0.25.0 0.29.0+1
test ^0.12.24+8 0.12.42 1.0.0
Transitive dependencies
analyzer 0.32.1
args 1.4.3
async 2.0.7
boolean_selector 1.0.3
charcode 1.1.1
convert 2.0.1
crypto 2.0.5
csslib 0.14.4
front_end 0.1.1
glob 1.1.5
html 0.13.3+1
http 0.11.3+16
http_multi_server 2.0.5
http_parser 3.1.2
io 0.3.2+1
js 0.6.1
json_rpc_2 2.0.8
kernel 0.3.1
logging 0.11.3+1
matcher 0.12.3
meta 1.1.5
mime 0.9.6+1
multi_server_socket 1.0.1
node_preamble 1.4.2
package_config 1.0.3
package_resolver 1.0.3
path 1.6.1
plugin 0.2.0+2
pool 1.3.5
pub_semver 1.4.1
shelf 0.7.3+1
shelf_packages_handler 1.0.3
shelf_static 0.2.7+1
shelf_web_socket 0.2.2+2
source_map_stack_trace 1.1.4
source_maps 0.10.5
source_span 1.4.0
stack_trace 1.9.2
stream_channel 1.6.7+1
string_scanner 1.0.2
term_glyph 1.0.0
typed_data 1.1.5
utf 0.9.0+4
vm_service_client 0.2.4+3
watcher 0.9.7+8
web_socket_channel 1.0.8
yaml 2.1.14