https://github.com/jolin-io/exprparsers.jl

Parse common Expr patterns. Speed up the process of defining stable macros.
https://github.com/jolin-io/exprparsers.jl

ast expr julia parser

Last synced: 3 months ago
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Parse common Expr patterns. Speed up the process of defining stable macros.

• Host: GitHub
• URL: https://github.com/jolin-io/exprparsers.jl
• Owner: jolin-io
• License: mit
• Created: 2020-04-24T18:28:31.000Z (almost 5 years ago)
• Default Branch: main
• Last Pushed: 2023-07-19T16:08:35.000Z (over 1 year ago)
• Last Synced: 2024-10-11T07:13:29.994Z (4 months ago)
• Topics: ast, expr, julia, parser
• Language: Julia
• Homepage: https://jolin-io.github.io/ExprParsers.jl/stable
• Size: 502 KB
• Stars: 7
• Watchers: 2
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGELOG.md
  • License: LICENSE

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README

        
# ExprParsers.jl

[![Stable](https://img.shields.io/badge/docs-stable-blue.svg)](https://jolin-io.github.io/ExprParsers.jl/stable)

[![Dev](https://img.shields.io/badge/docs-dev-blue.svg)](https://jolin-io.github.io/ExprParsers.jl/dev)

[![Build Status](https://github.com/jolin-io/ExprParsers.jl/workflows/CI/badge.svg)](https://github.com/jolin-io/ExprParsers.jl/actions)

[![Coverage](https://codecov.io/gh/jolin-io/ExprParsers.jl/branch/main/graph/badge.svg)](https://codecov.io/gh/jolin-io/ExprParsers.jl)

`ExprParsers` is a library made to simplify development of elaborate macros.

What `ExprParsers` offers is a set of curated parsers for common `Expr` patterns. For example

```julia

parse_expr(ExprParsers.Function(), :(f(a) = 2a))

```

will give you an `ExprParsers.Function_Parsed` object where you can inspect and change `name`, `args`, `kwargs`, `curlies`, `wheres`, and the function `body`. It just works and you don't have to bother any longer that you can also write the same function as `function f(a); 2a; end` - the parser handles this for you.

In macros you often not only want to inspect the given `Expr` in efficient and stable manners, but also may want to change parts and return a respectively adapted `Expr`. For this purpose, all Parsed objects are mutable and can be converted back to `Expr` by using the `to_expr(parsed_value)` method.

We guarantee that `parse_expr` and `to_expr` are working nicely together, i.e. the following always holds for arbitrary expressions and parsers

```julia

julia> using ExprParsers

julia> # comes with a shorthand EP for ExprParsers

julia> parser = EP.Function()

EP.Function(

  name    = ExprParsers.Isa{Any}()

  curlies = ExprParsers.Isa{Any}()

  args    = ExprParsers.Isa{Any}()

  kwargs  = ExprParsers.Isa{Any}()

  wheres  = ExprParsers.Isa{Any}()

  body    = ExprParsers.Isa{Any}()

)

julia> expr = :(f(a) = 2a)

:(f(a) = begin

          #= REPL[8]:1 =#

          2a

      end)

julia> parsed = parse_expr(parser, expr)

EP.Function_Parsed(

  name    = :f

  curlies = Any[]

  args    = Any[:a]

  kwargs  = Any[]

  wheres  = Any[]

  body    = quote

    #= REPL[8]:1 =#

    2a

end

)

julia> # applying the parser "twice" returns always the same parsed result

julia> parse_expr(parser, to_expr(parsed)) == parsed

true

```

Note that `ExprParsers` exports a constant `EP` which is an alias for the package `ExprParsers` itself. This comes in very handy when you use the custom parsers a lot.

Checkout the `test/` directory for seeing more examples, especially [test/expr_parsers_with_parsed.jl](test/expr_parsers_with_parsed.jl) where for each common `Expr` pattern a parser is put into action.

## Installation

install by

```julia

using Pkg

pkg"add ExprParsers"

```