83 lines
1.7 KiB
Rust
83 lines
1.7 KiB
Rust
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use crate::sql::comment::mightbespace;
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use crate::sql::definition::{definition, Definition};
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use crate::sql::literal::Literal;
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use crate::sql::operator::{operator, Operator};
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use nom::branch::alt;
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use nom::IResult;
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use serde::{Deserialize, Serialize};
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use std::fmt;
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use std::str;
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#[derive(Clone, Debug, Default, Eq, Hash, PartialEq, Serialize, Deserialize)]
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pub struct Expression {
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#[serde(skip_serializing_if = "Option::is_none")]
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pub lhs: Option<Box<Definition>>,
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#[serde(skip_serializing_if = "Option::is_none")]
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pub op: Option<Operator>,
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#[serde(skip_serializing_if = "Option::is_none")]
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pub rhs: Option<Box<Expression>>,
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}
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impl<'a> From<&'a str> for Expression {
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fn from(s: &str) -> Self {
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expression(s).unwrap().1
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}
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}
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impl From<Literal> for Expression {
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fn from(v: Literal) -> Self {
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Expression {
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lhs: Some(Box::new(Definition::from(v))),
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op: None,
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rhs: None,
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}
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}
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}
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impl fmt::Display for Expression {
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fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
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if let Some(ref lhs) = self.lhs {
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write!(f, "{}", lhs)?
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}
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if let Some(ref op) = self.op {
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write!(f, " {} ", op)?
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}
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if let Some(ref rhs) = self.rhs {
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write!(f, "{}", rhs)?
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}
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Ok(())
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}
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}
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pub fn expression(i: &str) -> IResult<&str, Expression> {
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alt((dual, lone))(i)
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}
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fn dual(i: &str) -> IResult<&str, Expression> {
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let (i, l) = definition(i)?;
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let (i, _) = mightbespace(i)?;
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let (i, o) = operator(i)?;
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let (i, _) = mightbespace(i)?;
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let (i, r) = expression(i)?;
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Ok((
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i,
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Expression {
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lhs: Some(Box::new(l)),
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op: Some(o),
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rhs: Some(Box::new(r)),
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},
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))
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}
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fn lone(i: &str) -> IResult<&str, Expression> {
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let (i, l) = definition(i)?;
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Ok((
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i,
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Expression {
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lhs: Some(Box::new(l)),
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op: None,
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rhs: None,
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},
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))
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}
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