sv-parser/src/parser/behavioral_statements/conditional_statements.rs
2019-07-12 16:16:28 +09:00

100 lines
2.6 KiB
Rust

use crate::ast::*;
use crate::parser::*;
use nom::branch::*;
use nom::combinator::*;
use nom::multi::*;
use nom::sequence::*;
use nom::IResult;
// -----------------------------------------------------------------------------
#[derive(Debug)]
pub struct ConditionalStatement<'a> {
pub nodes: (
Option<UniquePriority<'a>>,
Symbol<'a>,
Paren<'a, CondPredicate<'a>>,
StatementOrNull<'a>,
Vec<(
Symbol<'a>,
Symbol<'a>,
Paren<'a, CondPredicate<'a>>,
StatementOrNull<'a>,
)>,
Option<(Symbol<'a>, StatementOrNull<'a>)>,
),
}
#[derive(Debug, Node)]
pub enum UniquePriority<'a> {
Unique(Symbol<'a>),
Unique0(Symbol<'a>),
Priority(Symbol<'a>),
}
#[derive(Debug)]
pub struct CondPredicate<'a> {
pub nodes: (List<Symbol<'a>, ExpressionOrCondPattern<'a>>,),
}
#[derive(Debug)]
pub enum ExpressionOrCondPattern<'a> {
Expression(Expression<'a>),
CondPattern(CondPattern<'a>),
}
#[derive(Debug)]
pub struct CondPattern<'a> {
pub nodes: (Expression<'a>, Symbol<'a>, Pattern<'a>),
}
// -----------------------------------------------------------------------------
pub fn conditional_statement(s: Span) -> IResult<Span, ConditionalStatement> {
let (s, a) = opt(unique_priority)(s)?;
let (s, b) = symbol("if")(s)?;
let (s, c) = paren(cond_predicate)(s)?;
let (s, d) = statement_or_null(s)?;
let (s, e) = many0(tuple((
symbol("else"),
symbol("if"),
paren(cond_predicate),
statement_or_null,
)))(s)?;
let (s, f) = opt(pair(symbol("else"), statement_or_null))(s)?;
Ok((
s,
ConditionalStatement {
nodes: (a, b, c, d, e, f),
},
))
}
pub fn unique_priority(s: Span) -> IResult<Span, UniquePriority> {
alt((
map(symbol("unique0"), |x| UniquePriority::Unique0(x)),
map(symbol("unique"), |x| UniquePriority::Unique(x)),
map(symbol("priority"), |x| UniquePriority::Priority(x)),
))(s)
}
pub fn cond_predicate(s: Span) -> IResult<Span, CondPredicate> {
let (s, a) = list(symbol("&&&"), expression_or_cond_pattern)(s)?;
Ok((s, CondPredicate { nodes: (a,) }))
}
pub fn expression_or_cond_pattern(s: Span) -> IResult<Span, ExpressionOrCondPattern> {
alt((
map(expression, |x| ExpressionOrCondPattern::Expression(x)),
map(cond_pattern, |x| ExpressionOrCondPattern::CondPattern(x)),
))(s)
}
pub fn cond_pattern(s: Span) -> IResult<Span, CondPattern> {
let (s, a) = expression(s)?;
let (s, b) = symbol("matches")(s)?;
let (s, c) = pattern(s)?;
Ok((s, CondPattern { nodes: (a, b, c) }))
}