78 lines
2.2 KiB
Rust
78 lines
2.2 KiB
Rust
//! This example grabs input from stdin or a file, lexes it, parses it, and interprets it
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use conlang::{interpreter::Interpreter, lexer::Lexer, parser::Parser};
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use std::{
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error::Error,
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io::{stdin, stdout, IsTerminal, Write},
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path::{Path, PathBuf},
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};
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fn main() -> Result<(), Box<dyn Error>> {
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let conf = Config::new();
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if conf.paths.is_empty() {
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take_stdin()?;
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} else {
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for path in conf.paths.iter().map(PathBuf::as_path) {
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parse(&std::fs::read_to_string(path)?, Some(path))?;
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}
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}
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Ok(())
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}
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struct Config {
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paths: Vec<PathBuf>,
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}
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impl Config {
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fn new() -> Self {
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Config { paths: std::env::args().skip(1).map(PathBuf::from).collect() }
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}
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}
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fn take_stdin() -> Result<(), Box<dyn Error>> {
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const PROMPT: &str = "> ";
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if stdin().is_terminal() {
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let mut interpreter = Interpreter::new();
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print!("{PROMPT}");
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stdout().flush()?;
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for line in stdin().lines() {
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let line = line?;
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if !line.is_empty() {
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let _ = run(&line, &mut interpreter).map_err(|e| eprintln!("{e}"));
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println!();
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}
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print!("{PROMPT}");
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stdout().flush()?;
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}
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} else {
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parse(&std::io::read_to_string(stdin())?, None)?
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}
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Ok(())
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}
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fn parse(file: &str, path: Option<&Path>) -> Result<(), Box<dyn Error>> {
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match Parser::from(Lexer::new(file)).parse() {
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Ok(ast) => Interpreter::new().interpret(&ast)?,
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Err(e) if e.start().is_some() => print!("{:?}:{}", path.unwrap_or(Path::new("-")), e),
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Err(e) => print!("{e}"),
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}
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println!();
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Ok(())
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}
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fn run(file: &str, interpreter: &mut Interpreter) -> Result<(), Box<dyn Error>> {
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// If it parses successfully as a program, run the program
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match Parser::from(Lexer::new(file)).parse() {
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Ok(ast) => interpreter.interpret(&ast)?,
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Err(e) => {
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// If not, re-parse as an expression, and print the stack
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let Ok(expr) = Parser::from(Lexer::new(file)).parse_expr() else {
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Err(e)?
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};
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for value in interpreter.eval(&expr)? {
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println!("{value}");
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}
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}
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}
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Ok(())
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}
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