tada/src/parser/var.rs

88 lines
2.3 KiB
Rust

//! Corresponds to `ast::var`.
use chumsky::prelude::*;
use crate::ast::{Expr, Ident, Space, Var};
use super::basic::{EParser, Error};
fn var_access(space: EParser<Space>, expr: EParser<Expr>) -> impl Parser<char, Var, Error = Error> {
just('[')
.ignore_then(space.clone())
.then(expr)
.then(space)
.then_ignore(just(']'))
.map_with_span(|((s0, index), s1), span| Var::Access {
s0,
index: Box::new(index),
s1,
span,
})
}
fn var_assign(
space: EParser<Space>,
local: EParser<Option<Space>>,
expr: EParser<Expr>,
) -> impl Parser<char, Var, Error = Error> {
local
.then_ignore(just('['))
.then(space.clone())
.then(expr.clone())
.then(space.clone())
.then_ignore(just(']'))
.then(space.clone())
.then_ignore(just('='))
.then(space)
.then(expr)
.map_with_span(
|((((((local, s0), index), s1), s2), s3), value), span| Var::Assign {
local,
s0,
index: Box::new(index),
s1,
s2,
s3,
value: Box::new(value),
span,
},
)
}
fn var_assign_ident(
space: EParser<Space>,
ident: EParser<Ident>,
local: EParser<Option<Space>>,
expr: EParser<Expr>,
) -> impl Parser<char, Var, Error = Error> {
local
.then(ident)
.then(space.clone())
.then_ignore(just('='))
.then(space)
.then(expr)
.map_with_span(
|((((local, name), s0), s1), value), span| Var::AssignIdent {
local,
name,
s0,
s1,
value: Box::new(value),
span,
},
)
}
pub fn var(
space: EParser<Space>,
ident: EParser<Ident>,
local: EParser<Option<Space>>,
expr: EParser<Expr>,
) -> EParser<Var> {
let access = var_access(space.clone(), expr.clone());
let assign = var_assign(space.clone(), local.clone(), expr.clone());
let access_ident = ident.clone().map(Var::AccessIdent);
let assign_ident = var_assign_ident(space, ident, local, expr);
assign.or(access).or(assign_ident).or(access_ident).boxed()
}