meilisearch/filter-parser/src/condition.rs

71 lines
2.4 KiB
Rust

//! BNF grammar:
//!
//! ```text
//! condition = value ("==" | ">" ...) value
//! to = value value TO value
//! ```
use nom::branch::alt;
use nom::bytes::complete::tag;
use nom::character::complete::multispace1;
use nom::combinator::cut;
use nom::sequence::{terminated, tuple};
use Condition::*;
use crate::{parse_value, FilterCondition, IResult, Span, Token};
#[derive(Debug, Clone, PartialEq, Eq)]
pub enum Condition<'a> {
GreaterThan(Token<'a>),
GreaterThanOrEqual(Token<'a>),
Equal(Token<'a>),
NotEqual(Token<'a>),
Exists,
LowerThan(Token<'a>),
LowerThanOrEqual(Token<'a>),
Between { from: Token<'a>, to: Token<'a> },
}
/// condition = value ("==" | ">" ...) value
pub fn parse_condition(input: Span) -> IResult<FilterCondition> {
let operator = alt((tag("<="), tag(">="), tag("!="), tag("<"), tag(">"), tag("=")));
let (input, (fid, op, value)) = tuple((parse_value, operator, cut(parse_value)))(input)?;
let condition = match *op.fragment() {
"<=" => FilterCondition::Condition { fid, op: LowerThanOrEqual(value) },
">=" => FilterCondition::Condition { fid, op: GreaterThanOrEqual(value) },
"!=" => FilterCondition::Condition { fid, op: NotEqual(value) },
"<" => FilterCondition::Condition { fid, op: LowerThan(value) },
">" => FilterCondition::Condition { fid, op: GreaterThan(value) },
"=" => FilterCondition::Condition { fid, op: Equal(value) },
_ => unreachable!(),
};
Ok((input, condition))
}
/// exist = value "EXISTS"
pub fn parse_exists(input: Span) -> IResult<FilterCondition> {
let (input, key) = terminated(parse_value, tag("EXISTS"))(input)?;
Ok((input, FilterCondition::Condition { fid: key.into(), op: Exists }))
}
/// exist = value "NOT" WS+ "EXISTS"
pub fn parse_not_exists(input: Span) -> IResult<FilterCondition> {
let (input, key) = parse_value(input)?;
let (input, _) = tuple((tag("NOT"), multispace1, tag("EXISTS")))(input)?;
Ok((
input,
FilterCondition::Not(Box::new(FilterCondition::Condition { fid: key.into(), op: Exists })),
))
}
/// to = value value "TO" WS+ value
pub fn parse_to(input: Span) -> IResult<FilterCondition> {
let (input, (key, from, _, _, to)) =
tuple((parse_value, parse_value, tag("TO"), multispace1, cut(parse_value)))(input)?;
Ok((input, FilterCondition::Condition { fid: key, op: Between { from, to } }))
}