# glex
[![Package Version](https://img.shields.io/hexpm/v/glex)](https://hex.pm/packages/glex)
[![Hex Docs](https://img.shields.io/badge/hex-docs-ffaff3)](https://hexdocs.pm/glex/)
## A simple lexer generator for Gleam
`glex` is a simple lexer generator for Gleam. It is inspired by the [`rply`](https://github.com/alex/rply) lexer generator and [`glexer`](https://github.com/DanielleMaywood/glexer).
```sh
gleam add glex
```
```gleam
import gleam/io
import gleam/list
import gleam/string
import glex
pub fn main() {
// Making a lexer for a simple rung of ladder logic
let file_type = "([A-Za-z]){1,2}"
let file_number = "([2-9]?[0-5]?[0-5]?)?"
let element_delimiter = "(:|/)"
let element_number = "(\\d{1,4}|[A-Za-z]{1,4})"
let word_delimiter = "([.|/])?"
let word_number = "(\\d{1,4}|[A-Za-z]{1,4})?"
let bit_delimiter = "(/)?"
let bit_number = "(\\d{1,4}|[A-Za-z]{1,4})?"
let address =
string.concat([
file_type,
file_number,
element_delimiter,
element_number,
word_delimiter,
word_number,
bit_delimiter,
bit_number,
])
let rung = "SOR XIC T4:0.1/DN OTE B3/0 EOR"
let tokens =
glex.new()
|> glex.add_rule("SOR", "SOR")
|> glex.add_rule("EOR", "EOR")
|> glex.add_rule("XIC", "XIC")
|> glex.add_rule("OTE", "OTE")
|> glex.add_rule("ADDRESS", address)
|> glex.add_ignore("whitespace", "\\s+")
|> glex.build(rung)
|> glex.lex()
tokens
|> list.each(io.debug)
// #(Valid("SOR", "SOR"), Position(0))
// #(Ignored("whitespace", " "), Position(3))
// #(Valid("XIC", "XIC"), Position(4))
// #(Ignored("whitespace", " "), Position(7))
// #(Valid("ADDRESS", "T4:0.1/DN"), Position(8))
// #(Ignored("whitespace", " "), Position(17))
// #(Valid("OTE", "OTE"), Position(18))
// #(Ignored("whitespace", " "), Position(21))
// #(Valid("ADDRESS", "B3/0"), Position(22))
// #(Ignored("whitespace", " "), Position(26))
// #(Valid("EOR", "EOR"), Position(27))
tokens
|> glex.ok()
|> io.debug
// True
tokens
|> glex.valid_only()
|> list.each(io.debug)
// #(Valid("SOR", "SOR"), Position(0))
// #(Valid("XIC", "XIC"), Position(4))
// #(Valid("ADDRESS", "T4:0.1/DN"), Position(8))
// #(Valid("OTE", "OTE"), Position(18))
// #(Valid("ADDRESS", "B3/0"), Position(22))
// #(Valid("EOR", "EOR"), Position(27))
}
```
Further documentation can be found at <https://hexdocs.pm/glex>.
## Development
```sh
gleam run # Run the project
gleam test # Run the tests
gleam shell # Run an Erlang shell
```