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use winnow::prelude::*;
mod parser;
mod parser_ast;
mod parser_lexer;
#[cfg(test)]
mod test_parser;
#[cfg(test)]
mod test_parser_ast;
#[cfg(test)]
mod test_parser_lexer;
fn main() -> Result<(), lexopt::Error> {
let args = Args::parse()?;
let input = args.input.as_deref().unwrap_or("1 + 1");
if let Err(err) = calc(input, args.implementation) {
println!("FAILED");
println!("{err}");
}
Ok(())
}
fn calc(
input: &str,
imp: Impl,
) -> Result<(), winnow::error::ParseError<&str, winnow::error::ContextError>> {
println!("{input} =");
match imp {
Impl::Eval => {
let result = parser::expr.parse(input)?;
println!(" {result}");
}
Impl::Ast => {
let result = parser_ast::expr.parse(input)?;
println!(" {:#?}={}", result, result.eval());
}
Impl::Lexer => {
let tokens = parser_lexer::tokens.parse(input)?;
println!(" {tokens:#?}");
let tokens = parser_lexer::Tokens::new(&tokens);
let result = parser_lexer::expr.parse(tokens).unwrap();
println!(" {:#?}={}", result, result.eval());
}
}
Ok(())
}
#[derive(Default)]
struct Args {
input: Option<String>,
implementation: Impl,
}
enum Impl {
Eval,
Ast,
Lexer,
}
impl Default for Impl {
fn default() -> Self {
Self::Eval
}
}
impl Args {
fn parse() -> Result<Self, lexopt::Error> {
use lexopt::prelude::*;
let mut res = Args::default();
let mut args = lexopt::Parser::from_env();
while let Some(arg) = args.next()? {
match arg {
Long("impl") => {
res.implementation = args.value()?.parse_with(|s| match s {
"eval" => Ok(Impl::Eval),
"ast" => Ok(Impl::Ast),
"lexer" => Ok(Impl::Lexer),
_ => Err("expected `eval`, `ast`"),
})?;
}
Value(input) => {
res.input = Some(input.string()?);
}
_ => return Err(arg.unexpected()),
}
}
Ok(res)
}
}
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