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// Copyright (C) 2019-2024 Aleo Systems Inc.
// This file is part of the Leo library.
// The Leo library is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
// The Leo library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// You should have received a copy of the GNU General Public License
// along with the Leo library. If not, see <https://www.gnu.org/licenses/>.
// ABNF PARSING RULES
//
// Header:
// ```abnf
// ; Introduction
// ; -------------
// ```
//
// Code block in docs (note double whitespace after colon):
// ```abnf
// ; code
// ; code
//```
//
// Rule:
// ```abnf
// address = "address"
// ```
//
// Line:
// ``` abnf
// ;;;;;;;;;
// ```
//
#![forbid(unsafe_code)]
use abnf::types::{Node, Rule};
use anyhow::{Result, anyhow};
use std::collections::{HashMap, HashSet};
/// Processor's scope. Used when code block or definition starts or ends.
#[derive(Debug, Clone)]
enum Scope {
Free,
Code,
Definition(Rule),
}
/// Transforms abnf file into Markdown.
#[derive(Debug, Clone)]
struct Processor<'a> {
rules: HashMap<String, Rule>,
grammar: &'a str,
scope: Scope,
line: u32,
out: String,
}
impl<'a> Processor<'a> {
fn new(grammar: &'a str, abnf: Vec<Rule>) -> Processor<'a> {
// we need a hashmap to pull rules easily
let rules: HashMap<String, Rule> = abnf.into_iter().map(|rule| (rule.name().to_string(), rule)).collect();
Processor { grammar, line: 0, out: String::new(), rules, scope: Scope::Free }
}
/// Main function for this struct.
/// Goes through each line and transforms it into proper markdown.
fn process(&mut self) {
let lines = self.grammar.lines();
let mut prev = "";
for line in lines {
self.line += 1;
// code block in comment (not highlighted as abnf)
if let Some(code) = line.strip_prefix("; ") {
self.enter_scope(Scope::Code);
self.append_str(code);
// just comment. end of code block
} else if let Some(code) = line.strip_prefix("; ") {
self.enter_scope(Scope::Free);
self.append_str(code);
// horizontal rule - section separator
} else if line.starts_with(";;;;;;;;;;") {
self.enter_scope(Scope::Free);
self.append_str("\n--------\n");
// empty line in comment. end of code block
} else if line.starts_with(';') {
self.enter_scope(Scope::Free);
self.append_str("\n\n");
// just empty line. end of doc, start of definition
} else if line.is_empty() {
self.enter_scope(Scope::Free);
self.append_str("");
// definition (may be multiline)
} else {
// if there's an equality sign and previous line was empty
if line.contains('=') && prev.is_empty() {
let (def, _) = line.split_at(line.find('=').unwrap());
let def = def.trim();
// try to find rule matching definition or fail
let rule = self.rules.get(def).cloned().unwrap();
self.enter_scope(Scope::Definition(rule));
}
self.append_str(line);
}
prev = line;
}
}
/// Append new line into output, add newline character.
fn append_str(&mut self, line: &str) {
self.out.push_str(line);
self.out.push('\n');
}
/// Enter new scope (definition or code block). Allows customizing
/// pre and post lines for each scope entered or exited.
fn enter_scope(&mut self, new_scope: Scope) {
match (&self.scope, &new_scope) {
// exchange scopes between Free and Code
(Scope::Free, Scope::Code) => self.append_str("```"),
(Scope::Code, Scope::Free) => self.append_str("```"),
// exchange scopes between Free and Definition
(Scope::Free, Scope::Definition(rule)) => {
self.append_str(&format!("<a name=\"{}\"></a>", rule.name()));
self.append_str("```abnf");
}
(Scope::Definition(rule), Scope::Free) => {
let mut rules: Vec<String> = Vec::new();
parse_abnf_node(rule.node(), &mut rules);
// 1. leave only unique keys
// 2. map each rule into a link
// 3. sort the links so they don't keep changing order
// 4. join results as a list
// Note: GitHub only allows custom tags with 'user-content-' prefix
let mut keyvec = rules
.into_iter()
.collect::<HashSet<_>>()
.into_iter()
.map(|tag| format!("[{}](#user-content-{tag})", &tag))
.collect::<Vec<String>>();
keyvec.sort();
let keys = keyvec.join(", ");
self.append_str("```");
if !keys.is_empty() {
self.append_str(&format!("\nGo to: _{keys}_;\n"));
}
}
(_, _) => (),
};
self.scope = new_scope;
}
}
/// Recursively parse ABNF Node and fill sum vec with found rule names.
fn parse_abnf_node(node: &Node, sum: &mut Vec<String>) {
match node {
// these two are just vectors of rules
Node::Alternatives(vec) | Node::Concatenation(vec) => {
for node in vec {
parse_abnf_node(node, sum);
}
}
Node::Group(node) | Node::Optional(node) => parse_abnf_node(node.as_ref(), sum),
// push rulename if it is known
Node::Rulename(name) => sum.push(name.clone()),
// do nothing for other nodes
_ => (),
}
}
fn main() -> Result<()> {
// Take Leo ABNF grammar file.
let args: Vec<String> = std::env::args().collect();
let abnf_path = if let Some(path) = args.get(1) {
std::path::Path::new(path)
} else {
return Err(anyhow!("Usage Error: expects one argument to abnf file to convert."));
};
let grammar = std::fs::read_to_string(abnf_path)?;
// Parse ABNF to get list of all definitions.
// Rust ABNF does not provide support for `%s` (case sensitive strings, part of
// the standard); so we need to remove all occurrences before parsing.
let parsed = abnf::rulelist(&str::replace(&grammar, "%s", "")).map_err(|e| {
eprintln!("{}", &e);
anyhow::anyhow!(e)
})?;
// Init parser and run it. That's it.
let mut parser = Processor::new(&grammar, parsed);
parser.process();
// Print result of conversion to STDOUT.
println!("{}", parser.out);
Ok(())
}