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|
use myslip::parse::parsetree::parse_to_ast;
use myslip::sexp::{SExp, SExp::*, SLeaf::Nil, util::scons};
use myslip::r#type::Type::NilType;
use std::{io, io::Write, io::Read, env};
use std::fs::File;
fn read_bind_files(
file_names: Vec<String>
) -> Result<Vec<SExp>, String> {
let mut res = vec![];
for name in file_names {
let mut file = File::open(name).map_err(|e| e.to_string())?;
let mut contents = String::new();
file.read_to_string(&mut contents)
.map_err(|e| e.to_string())?;
let exps = parse_to_ast(&contents)?.parts();
for exp in exps {
if exp.clone().check_let().is_some() {
res.push(exp);
} else {
return Err(format!("'{}' isn't a declaration", exp));
}
}
}
Ok(res)
}
fn read_file_to_execute(
file_name: String
) -> Result<SExp, String> {
let mut file = File::open(file_name)
.map_err(|e| e.to_string())?;
let mut contents = String::new();
file.read_to_string(&mut contents)
.map_err(|e| e.to_string())?;
match parse_to_ast(&contents) {
Ok(SCons(a, b)) if *b == Atom(Nil) => Ok(*a),
t => t
}
}
fn main() {
let mut file_to_execute: Option<String> = None;
let mut bind_files: Vec<String> = vec!["stdlib.slip".to_string()];
let mut next_is_load = false;
let mut no_stdlib = false;
let mut help = false;
for arg in env::args() {
if next_is_load {
bind_files.push(arg);
next_is_load = false;
continue;
}
match arg.as_str() {
s if s.ends_with("myslip") => continue,
"-l" | "--load" => next_is_load = true,
"--no-stdlib" => no_stdlib = true,
"--help" | "-h" | "-?" => help = true,
s => match file_to_execute {
Some(n) => {
println!("Error: can't execute both '{}' and '{}', please specify just one file. See '--help' for correct syntax.", s, n);
return;
},
None => file_to_execute = Some(s.to_string()),
}
}
}
if help {
println!("{}", String::from("") +
"myslip [options] [file]\n" +
"\n" +
"If [file] is given, executes the s-expression contained by\n" +
"the file. Otherwise starts the myslip repl.\n" +
"\n" +
"Options:\n" +
"\n" +
" --load [defs] | -l [defs] loads declarations from file\n" +
" named [defs] before execution\n" +
"\n" +
" --no-stdlib stops myslip from loading the\n" +
" standard library at startup\n" +
"\n" +
" --help | -h | -? displays this help message\n"
);
return;
}
if next_is_load {
println!(
"Error: '--load' can't be the last element of the argument list. See '--help' for correct syntax."
);
return;
}
if no_stdlib {
bind_files.remove(0);
}
let binds = match read_bind_files(bind_files) {
Ok(x) => x,
Err(e) => {
println!(
"Error reading declarations from files: {}",
e.to_string()
);
return;
}
};
match file_to_execute {
Some(name) => {
let exp = match read_file_to_execute(name) {
Ok(e) => e,
Err(e) => {
println!("Error reading source file: {e}");
return;
}
};
execute_expression(&binds, exp);
},
None => {
match repl(binds) {
Ok(()) => println!("bye :)"),
Err(e) => println!("Error: {}", e),
}
}
}
}
fn prompt_line(stdin: &io::Stdin, stdout: &mut io::Stdout) -> Result<(bool, String), io::Error> {
let mut line = String::new();
print!("> ");
match stdout.flush() {
Ok(_) => (),
Err(_) => println!("Enter s-expression:"),
};
let code = stdin.read_line(&mut line)?;
Ok((code == 0, line))
}
fn execute_expression(binds: &Vec<SExp>, mut exp: SExp) {
for bind in binds.into_iter().rev() {
exp = scons(bind.clone(), exp);
}
let ty = match exp
.type_check()
.map_err(|e| e.to_string()) {
Ok(t) => t,
Err(e) => {
println!("Type error: {}", e);
return;
},
};
let result = match exp.multistep() {
Ok(t) => t,
Err(e) => {
println!("Runtime error: {}", e);
return;
},
};
println!("{} : {}", result, ty);
}
fn repl(mut binds: Vec<SExp>) -> Result<(), io::Error> {
let stdin = io::stdin();
let mut stdout = io::stdout();
loop {
let (eof, input) = prompt_line(&stdin, &mut stdout)?;
if eof || input == "exit\n" {
break;
}
let orig_expression = match parse_to_ast(&input) {
Ok(SCons(a, b)) if *b == Atom(Nil) => *a,
Ok(t) => t,
Err(e) => {
println!("Syntax error: {}", e);
continue;
},
};
if let Some((name, _value)) = orig_expression.clone().check_let() {
let mut expr = scons(orig_expression.clone(), scons(Nil, Nil));
for i in 1..=binds.len() {
expr = scons(binds[binds.len() - i].clone(), expr);
}
match expr.type_check() {
Ok(NilType) => {
binds.push(orig_expression);
println!("{name} saved");
continue;
},
Err(e) => {
println!("Type error: {}", e);
continue;
},
Ok(_) => (),
}
}
execute_expression(&binds, orig_expression);
}
Ok(())
}
|
