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