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#![crate_name = "docopt_macros"]
#![crate_type = "dylib"]
#![feature(plugin_registrar, quote, rustc_private)]
extern crate syntax;
extern crate rustc_plugin;
extern crate docopt;
use std::borrow::Borrow;
use std::collections::HashMap;
use rustc_plugin::Registry;
use syntax::{ast, codemap, tokenstream};
use syntax::errors::DiagnosticBuilder;
use syntax::ext::base::{ExtCtxt, MacResult, MacEager, DummyResult};
use syntax::ext::build::AstBuilder;
use syntax::fold::Folder;
use syntax::parse::common::SeqSep;
use syntax::parse::parser::Parser;
use syntax::parse::token;
use syntax::print::pprust;
use syntax::ptr::P;
use syntax::symbol;
use syntax::util::small_vector::SmallVector;
use docopt::{Docopt, ArgvMap};
use docopt::parse::{Options, Atom, Positional, Zero, One};
type PResult<'a, T> = Result<T, DiagnosticBuilder<'a>>;
#[plugin_registrar]
pub fn plugin_registrar(reg: &mut Registry) {
reg.register_macro("docopt", expand);
}
fn expand(cx: &mut ExtCtxt, span: codemap::Span, tts: &[tokenstream::TokenTree])
-> Box<MacResult+'static> {
let parsed = match MacParser::new(cx, tts).parse() {
Ok(parsed) => parsed,
Err(_) => return DummyResult::any(span),
};
parsed.items(cx)
}
struct Parsed {
struct_info: StructInfo,
doc: Docopt,
types: HashMap<Atom, P<ast::Ty>>,
}
impl Parsed {
fn items(&self, cx: &ExtCtxt) -> Box<MacResult+'static> {
let mut its = vec!();
its.push(self.struct_decl(cx));
let struct_name = self.struct_info.name;
let full_doc = &*self.doc.parser().full_doc;
its.push(quote_item!(cx,
impl $struct_name {
#[allow(dead_code)]
fn docopt() -> docopt::Docopt {
docopt::Docopt::new($full_doc).unwrap()
}
}
).unwrap());
MacEager::items(SmallVector::many(its))
}
fn struct_decl(&self, cx: &ExtCtxt) -> P<ast::Item> {
let name = self.struct_info.name.clone();
let vis = if self.struct_info.public { ast::Visibility::Public }
else { ast::Visibility::Inherited };
let def = ast::VariantData::Struct(
self.struct_fields(cx), ast::DUMMY_NODE_ID);
let mut traits = vec!["Deserialize".to_string()];
traits.extend(self.struct_info.deriving.iter().cloned());
let attrs = vec![attribute(cx, "allow", vec!["non_snake_case"]),
attribute(cx, "derive", traits)];
let st = cx.item_struct(codemap::DUMMY_SP, name.clone(), def);
cx.item(codemap::DUMMY_SP, name, attrs, st.node.clone()).map(|mut it| {
it.vis = vis;
it
})
}
fn struct_fields(&self, cx: &ExtCtxt) -> Vec<ast::StructField> {
let mut fields: Vec<ast::StructField> = vec!();
for (atom, opts) in self.doc.parser().descs.iter() {
let name = ArgvMap::key_to_struct_field(&*atom.to_string());
let ty = match self.types.get(atom) {
None => self.pat_type(cx, atom, opts),
Some(ty) => ty.clone(),
};
fields.push(self.mk_struct_field(&*name, ty));
}
fields
}
fn pat_type(&self, cx: &ExtCtxt, atom: &Atom, opts: &Options) -> P<ast::Ty> {
let sp = codemap::DUMMY_SP;
match (opts.repeats, &opts.arg) {
(false, &Zero) => {
match atom {
&Positional(_) => cx.ty_ident(sp, ident("String")),
_ => cx.ty_ident(sp, ident("bool")),
}
}
(true, &Zero) => {
match atom {
&Positional(_) => ty_vec_string(cx),
_ => cx.ty_ident(sp, ident("usize")),
}
}
(false, &One(_)) => cx.ty_ident(sp, ident("String")),
(true, &One(_)) => ty_vec_string(cx),
}
}
fn mk_struct_field(&self, name: &str, ty: P<ast::Ty>) -> ast::StructField {
ast::StructField {
span: codemap::DUMMY_SP,
ident: Some(ident(name)),
vis: ast::Visibility::Public,
id: ast::DUMMY_NODE_ID,
ty: ty,
attrs: vec!(),
}
}
}
struct MacParser<'a, 'b:'a> {
cx: &'a mut ExtCtxt<'b>,
p: Parser<'b>,
}
impl<'a, 'b> MacParser<'a, 'b> {
fn new(cx: &'a mut ExtCtxt<'b>, tts: &[tokenstream::TokenTree]) -> MacParser<'a, 'b> {
let p = cx.new_parser_from_tts(tts);
MacParser { cx: cx, p: p }
}
fn parse(&mut self) -> PResult<'b, Parsed> {
if self.p.token == token::Eof {
let err = self.cx.struct_span_err(
self.cx.call_site(), "macro expects arguments");
return Err(err);
}
let struct_info = self.parse_struct_info()?;
let docstr = self.parse_str()?;
let mut types = HashMap::new();
if !self.p.check(&token::Eof) {
let sep = SeqSep {
sep: Some(token::Comma),
trailing_sep_allowed: true,
};
types = self.p.parse_seq_to_before_end(
&token::Eof, sep, |p| MacParser::parse_type_annotation(p)
).into_iter()
.map(|(ident, ty)| {
let field_name = ident.to_string();
let key = ArgvMap::struct_field_to_key(&*field_name);
(Atom::new(&*key), ty)
})
.collect::<HashMap<Atom, P<ast::Ty>>>();
self.p.expect(&token::Eof)?;
}
let doc = match Docopt::new(docstr) {
Ok(doc) => doc,
Err(err) => {
let err = self.cx.struct_span_err(
self.cx.call_site(),
&format!("Invalid Docopt usage: {}", err));
return Err(err);
}
};
Ok(Parsed {
struct_info: struct_info,
doc: doc,
types: types,
})
}
fn parse_str(&mut self) -> PResult<'b, String> {
fn lit_is_str(lit: &ast::Lit) -> bool {
match lit.node {
ast::LitKind::Str(_, _) => true,
_ => false,
}
}
fn lit_to_string(lit: &ast::Lit) -> String {
match lit.node {
ast::LitKind::Str(ref s, _) => s.to_string(),
_ => panic!("BUG: expected string literal"),
}
}
let exp = self.cx.expander().fold_expr(self.p.parse_expr().unwrap());
let s = match exp.node {
ast::ExprKind::Lit(ref lit) if lit_is_str(&**lit) => {
lit_to_string(&**lit)
}
_ => {
let err = format!("Expected string literal but got {}",
pprust::expr_to_string(&*exp));
let err = self.cx.struct_span_err(exp.span, &*err);
return Err(err);
}
};
self.p.bump();
Ok(s)
}
fn parse_type_annotation(p: &mut Parser<'b>)
-> PResult<'b, (ast::Ident, P<ast::Ty>)> {
let ident = p.parse_ident()?;
p.expect(&token::Colon)?;
let ty = p.parse_ty().unwrap();
Ok((ident, ty))
}
fn parse_struct_info(&mut self) -> PResult<'b, StructInfo> {
let public = self.p.eat_keyword(symbol::keywords::Pub);
let mut info = StructInfo {
name: self.p.parse_ident()?,
public: public,
deriving: vec![],
};
if self.p.eat(&token::Comma) { return Ok(info); }
let deriving = self.p.parse_ident()?;
if *deriving.name.as_str() != *"derive" {
let err = format!("Expected 'derive' keyword but got '{}'",
deriving);
let err = self.cx.struct_span_err(self.cx.call_site(), &*err);
return Err(err);
}
while !self.p.eat(&token::Comma) {
info.deriving.push(
self.p.parse_ident()?.name.to_string());
}
Ok(info)
}
}
struct StructInfo {
name: ast::Ident,
public: bool,
deriving: Vec<String>,
}
fn ident(s: &str) -> ast::Ident {
ast::Ident::with_empty_ctxt(symbol::Symbol::intern(s))
}
fn attribute<S, T>(cx: &ExtCtxt, name: S, items: Vec<T>) -> ast::Attribute
where S: Borrow<str>, T: Borrow<str> {
let sp = codemap::DUMMY_SP;
let its = items.into_iter().map(|s| meta_item(cx, s.borrow())).collect();
let mi = cx.meta_list(sp, intern(name.borrow()), its);
cx.attribute(sp, mi)
}
fn meta_item(cx: &ExtCtxt, s: &str) -> codemap::Spanned<ast::NestedMetaItemKind> {
codemap::Spanned {
node: ast::NestedMetaItemKind::MetaItem(cx.meta_word(codemap::DUMMY_SP, intern(s))),
span: cx.call_site(),
}
}
fn intern(s: &str) -> symbol::Symbol {
symbol::Symbol::intern(s)
}
fn ty_vec_string(cx: &ExtCtxt) -> P<ast::Ty> {
let sp = codemap::DUMMY_SP;
let tystr = ast::AngleBracketedParameterData {
span: sp,
lifetimes: vec![],
types: vec![cx.ty_ident(sp, ident("String"))],
bindings: vec![],
};
cx.ty_path(ast::Path {
span: sp,
segments: vec![ast::PathSegment {
span: sp,
identifier: ident("Vec"),
parameters: Some(P(ast::PathParameters::AngleBracketed(tystr))),
}]
})
}