extern crate proc_macro;
use std::iter;
use proc_macro::{Group, Span, TokenStream, TokenTree};
#[doc(hidden)]
#[proc_macro]
pub fn __cmd(macro_arg: TokenStream) -> TokenStream {
let (cmd, literal) = {
let mut iter = macro_arg.into_iter();
let cmd = iter.next().unwrap();
let literal = iter.next().unwrap();
assert!(iter.next().is_none());
(cmd, literal)
};
let literal_text = literal.to_string();
let mut args = shell_lex(literal_text.as_str(), literal.span());
let mut res = TokenStream::new();
{
let (_joined_to_prev, splat, program) = args.next().expect("command line is empty!");
assert!(!splat);
res.extend(Some(cmd));
res.extend(parse_ts("::new"));
res.extend(program);
}
for (joined_to_prev, splat, arg) in args {
assert!(!(joined_to_prev && splat));
let method = match (joined_to_prev, splat) {
(false, false) => ".arg",
(false, true) => ".args",
(true, false) => ".__extend_arg",
(true, true) => panic!("can't splat and contat simultaneously"),
};
res.extend(parse_ts(method));
res.extend(arg);
}
res
}
fn shell_lex(cmd: &str, call_site: Span) -> impl Iterator<Item = (bool, bool, TokenStream)> + '_ {
fn trim_decorations(s: &str) -> &str {
&s[1..s.len() - 1]
}
tokenize(cmd).map(move |token| {
let mut splat = false;
let ts = match token.kind {
TokenKind::Word => parse_ts(&format!("(\"{}\")", token.text)),
TokenKind::String => parse_ts(&format!("(\"{}\")", trim_decorations(token.text))),
TokenKind::Interpolation { splat: s } => {
splat = s;
let text = trim_decorations(token.text);
let ts = if splat {
format!("({})", &text[..text.len() - "...".len()])
} else {
format!("(&({}))", trim_decorations(token.text))
};
respan(parse_ts(&ts), call_site)
}
};
(token.joined_to_prev, splat, ts)
})
}
fn tokenize(cmd: &str) -> impl Iterator<Item = Token<'_>> + '_ {
let mut cmd = cmd.trim_matches('"');
iter::from_fn(move || {
let old_len = cmd.len();
cmd = cmd.trim_start();
let joined_to_prev = old_len == cmd.len();
if cmd.is_empty() {
return None;
}
let (len, kind) = next_token(cmd);
let token = Token { joined_to_prev, text: &cmd[..len], kind };
cmd = &cmd[len..];
Some(token)
})
}
#[derive(Debug)]
struct Token<'a> {
joined_to_prev: bool,
text: &'a str,
kind: TokenKind,
}
#[derive(Debug)]
enum TokenKind {
Word,
String,
Interpolation { splat: bool },
}
fn next_token(s: &str) -> (usize, TokenKind) {
if s.starts_with('{') {
let len = s.find('}').unwrap() + 1;
let splat = s[..len].ends_with("...}");
return (len, TokenKind::Interpolation { splat });
}
if s.starts_with('\'') {
let len = s[1..].find('\'').unwrap() + 2;
return (len, TokenKind::String);
}
let len =
s.find(|it: char| it.is_ascii_whitespace() || it == '\'' || it == '{').unwrap_or(s.len());
(len, TokenKind::Word)
}
fn respan(ts: TokenStream, span: Span) -> TokenStream {
let mut res = TokenStream::new();
for tt in ts {
let tt = match tt {
TokenTree::Ident(mut ident) => {
ident.set_span(ident.span().resolved_at(span));
TokenTree::Ident(ident)
}
TokenTree::Group(group) => {
TokenTree::Group(Group::new(group.delimiter(), respan(group.stream(), span)))
}
_ => tt,
};
res.extend(Some(tt))
}
res
}
fn parse_ts(s: &str) -> TokenStream {
s.parse().unwrap()
}