A directional shell
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2.8 KiB

use crate::graph::{Graph, Node};
use std::collections::HashMap;
use std::fmt::Error;
enum State {
Default,
Edge,
Node(String),
AnonymousNode,
}
struct Consumer {
lines: Vec<String>,
state: ConsumerState,
}
struct ConsumerState {
line: usize,
position: usize,
absolute_position: u64,
}
impl Consumer {
fn consume_from_line(&mut self) -> Option<char> {
if let Some(chxr) = self.peek_on_line() {
self.push_char();
Some(chxr)
} else {
None
}
}
fn peek_on_line(&mut self) -> Option<char> {
let line = &self.lines[self.state.line];
if self.state.position + 1 >= line.len() {
None
} else {
Ok(line[self.state.position + 1])
}
}
fn push_char(&mut self) {
self.state.position += 1;
self.state.absolute_position += 1;
}
fn new(content: String) -> Consumer {
Consumer {
lines: content
.lines()
.map(|x| String::from(x))
.collect(),
state: ConsumerState {
position: 0,
line: 0,
absolute_position: 0,
},
}
}
}
pub struct ParserError {
message: String,
absolute_position: u64,
position: usize,
line: usize,
}
impl ParserError {
fn from_consumer(consumer: &Consumer, error: &str) -> ParserError {
ParserError {
message: error.to_string(),
absolute_position: consumer.state.absolute_position,
position: consumer.state.position,
line: consumer.state.line
}
}
}
pub fn parse(contents: String) -> Result<Graph, ParserError> {
let mut nodes: Vec<Node>;
let mut node_names: HashMap<String, u32>;
let mut state = State::Default;
let mut consumer = Consumer::new(contents);
while consumer.consume_line() {
while let Some(chxr) = consumer.consume_from_line() {
match state {
State::Default => {
match chxr {
'\\' => {
if consumer.peek_on_line() == Some('(') {
consumer.consume_from_line();
state = State::AnonymousNode;
} else {
return Err(ParserError::from_consumer(&consumer, "Found \\ without valid next character"));
}
}
'a'..'z' | 'A'..'Z' => {
state = State::Node(chxr.to_string())
}
}
}
_ => {}
}
}
}
println!("{:?}", lines);
Ok(Graph::default())
}