use super::{NormResult, NormError};
use super::norm_util::{self, Symbols};
use grammar::parse_tree::*;
use grammar::repr;
use intern::{intern, InternedString};
use util::{Multimap, Sep, set};
#[cfg(test)]
mod test;
pub fn validate(grammar: &Grammar) -> NormResult<()> {
let extern_token: Option<&ExternToken> =
grammar.items
.iter()
.filter_map(|item| item.as_extern_token())
.next();
let validator = Validator {
grammar: grammar,
extern_token: extern_token,
};
validator.validate()
}
struct Validator<'grammar> {
grammar: &'grammar Grammar,
extern_token: Option<&'grammar ExternToken>,
}
impl<'grammar> Validator<'grammar> {
fn validate(&self) -> NormResult<()> {
if let Some(ref algorithm) = self.grammar.algorithm {
match repr::Algorithm::from_str(algorithm.text) {
Some(_) => { }
None => {
return_err!(
algorithm.span,
"unrecognized algorithm `{}`", algorithm.text);
}
}
}
for item in &self.grammar.items {
match *item {
GrammarItem::Use(..) => { }
GrammarItem::ExternToken(ref data) => {
if data.span != self.extern_token.unwrap().span {
return_err!(
data.span,
"multiple extern token definitions are not permitted");
}
let allowed_names = vec![intern(LOCATION), intern(ERROR)];
let mut new_names = set();
for associated_type in &data.associated_types {
if !allowed_names.contains(&associated_type.type_name) {
return_err!(
associated_type.type_span,
"associated type `{}` not recognized, \
try one of the following: {}",
associated_type.type_name,
Sep(", ", &allowed_names));
} else if !new_names.insert(associated_type.type_name) {
return_err!(
associated_type.type_span,
"associated type `{}` already specified",
associated_type.type_name);
}
}
match data.enum_token.type_name {
TypeRef::Id(_) | TypeRef::Nominal { .. } => { }
_ => {
return_err!(
data.enum_token.type_span,
"expected a nominal type here, like `Token` or `foo::Token<T>`");
}
}
}
GrammarItem::Nonterminal(ref data) => {
for alternative in &data.alternatives {
try!(self.validate_alternative(alternative));
}
}
}
}
Ok(())
}
fn validate_alternative(&self,
alternative: &Alternative)
-> NormResult<()> {
try!(self.validate_expr(&alternative.expr));
match norm_util::analyze_expr(&alternative.expr) {
Symbols::Named(syms) => {
if alternative.action.is_none() {
let sym =
syms.iter()
.map(|&(_, _, sym)| sym)
.next()
.unwrap();
return_err!(
sym.span,
"named symbols (like `{}`) require a custom action",
sym);
}
}
Symbols::Anon(_) => { }
}
Ok(())
}
fn validate_expr(&self,
expr: &ExprSymbol)
-> NormResult<()> {
for symbol in &expr.symbols {
try!(self.validate_symbol(symbol));
}
let chosen: Vec<&Symbol> =
expr.symbols.iter()
.filter(|sym| match sym.kind {
SymbolKind::Choose(_) => true,
_ => false,
})
.collect();
let named: Multimap<InternedString, &Symbol> =
expr.symbols.iter()
.filter_map(|sym| match sym.kind {
SymbolKind::Name(nt, _) => Some((nt, sym)),
_ => None,
})
.collect();
if !chosen.is_empty() && !named.is_empty() {
return_err!(chosen[0].span,
"anonymous symbols like this one cannot be combined with \
named symbols like `{}`",
named.into_iter().next().unwrap().1[0]);
}
for (name, syms) in named.into_iter() {
if syms.len() > 1{
return_err!(syms[1].span,
"multiple symbols named `{}` are not permitted",
name);
}
}
Ok(())
}
fn validate_symbol(&self,
symbol: &Symbol)
-> NormResult<()> {
match symbol.kind {
SymbolKind::Expr(ref expr) => {
try!(self.validate_expr(expr));
}
SymbolKind::AmbiguousId(_) => {
}
SymbolKind::Terminal(_) => {
}
SymbolKind::Nonterminal(_) => {
}
SymbolKind::Macro(ref msym) => {
debug_assert!(msym.args.len() > 0);
for arg in &msym.args {
try!(self.validate_symbol(arg));
}
}
SymbolKind::Repeat(ref repeat) => {
try!(self.validate_symbol(&repeat.symbol));
}
SymbolKind::Choose(ref sym) | SymbolKind::Name(_, ref sym) => {
try!(self.validate_symbol(sym));
}
SymbolKind::Lookahead | SymbolKind::Lookbehind => {
if self.extern_token.is_none() {
return_err!(symbol.span,
"lookahead/lookbehind not permitted without \
an extern token declaration");
}
let loc = intern(LOCATION);
if self.extern_token.unwrap().associated_type(loc).is_none() {
return_err!(
symbol.span,
"lookahead/lookbehind require you to declare the type of \
a location; add a `type {} = ..` statement to the extern token \
block",
LOCATION);
}
}
}
Ok(())
}
}