MIT license

40KB
798 lines

Pest Tree

An alternative to pest_ast for converting dynamically typed pest trees into statically typed ones, using macros

This documentation is currently unfinished and some may be outdated. Feel free to directly ask in github issues if you have any problems!

This crate revolves around the trait PestTree which can be derived for Structs and Enums.

Options

Name	Parameters	Purpose
strategy(...)	A `strategy`, such as `Direct` or `Sequential`	Specify a matcher strategy for the struct/enum.
require(...)	A `Requirement`, such as `Rule(...)`	Define requirements not covered by the struct's rules/strategy.
convert(...)	A `Converter`, such as `auto`	Convert the `Pairs` into something like an `i32` in a struct

Name	Parameters	Purpose
`Direct`	None	Match tokens like `in`, `let`, etc.
`Sequential`	None	Match a series of tokens, such as `let a = 3;`

Name	Parameters	Purpose
`rule(...)`	A `Rule` enum variant generated by `pest_derive`	Confirm that the `Pairs` matches a rule. This requirement should be used in most if not all structs/enums
`validate(...)`	A closure or a function that accepts a `Pair` and returns `true` if the input is accepted	Match based on custom conditions.
`any(...)`	Two or more `Requirement`s	Only 1 requirement in `or(...)` have to match for it to be accepted. For functionality like `and(...)`, just use multiple `require` attributes

Name	Parameters	Purpose
`custom_p(...)`	A closure or a function that takes a `Pair` and outputs the type it should convert to.	Convert tokens into custom types.
`custom_s(...)`	A closure or a function that accepts a `&str` and returns `true` if the input is accepted	Convert tokens into custom types.
`auto`	None	Automatically convert the `pair` into one of the basic types (`pest_tree` will determine the type based on your struct member declaration)
`chain(...)`	Chain many functions together in sequence	Chain functions that convert from a pair into a custom type

PestTree needs helper attributes to determine how the tree can be parsed. For examples on how they can be used, check the examples folder.

An easy and simple way to convert your dynamic [pest] trees into an AST built from structs and enums.

This crate is centered around the pest_tree_derive::PestTree derive macro. The macro uses the pest_tree attribute macro to help derive the trait pest_tree_derive::PestTree for the relevant struct/enum.

~4MB
~77K SLoC