sv-parser/src/parser/behavioral_statements/conditional_statements.rs
2019-07-24 21:53:51 +09:00

106 lines
2.8 KiB
Rust

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