just/src/expression.rs
Casey Rodarmor 30c77f8d03
Resolve recipe dependencies (#547)
Make analysis resolve recipe dependencies from names (`Name`) to recipes
(`Rc<Recipe>`), to give type-level certainty that resolution was performed
correctly and remove the need to look up dependencies on run.
2019-11-21 08:23:32 -06:00

70 lines
2.0 KiB
Rust

use crate::common::*;
/// An expression. Note that the Just language grammar has both an
/// `expression` production of additions (`a + b`) and values, and a
/// `value` production of all other value types (for example strings,
/// function calls, and parenthetical groups).
///
/// The parser parses both values and expressions into `Expression`s.
#[derive(PartialEq, Debug)]
pub(crate) enum Expression<'src> {
/// `contents`
Backtick {
contents: &'src str,
token: Token<'src>,
},
/// `name(arguments)`
Call {
function: Name<'src>,
arguments: Vec<Expression<'src>>,
},
/// `lhs + rhs`
Concatination {
lhs: Box<Expression<'src>>,
rhs: Box<Expression<'src>>,
},
/// `(contents)`
Group { contents: Box<Expression<'src>> },
/// `"string_literal"` or `'string_literal'`
StringLiteral { string_literal: StringLiteral<'src> },
/// `variable`
Variable { name: Name<'src> },
}
impl<'src> Expression<'src> {
pub(crate) fn variables<'expression>(&'expression self) -> Variables<'expression, 'src> {
Variables::new(self)
}
pub(crate) fn functions<'expression>(&'expression self) -> Functions<'expression, 'src> {
Functions::new(self)
}
}
impl<'src> Display for Expression<'src> {
fn fmt(&self, f: &mut Formatter) -> Result<(), fmt::Error> {
match self {
Expression::Backtick { contents, .. } => write!(f, "`{}`", contents)?,
Expression::Concatination { lhs, rhs } => write!(f, "{} + {}", lhs, rhs)?,
Expression::StringLiteral { string_literal } => write!(f, "{}", string_literal)?,
Expression::Variable { name } => write!(f, "{}", name.lexeme())?,
Expression::Call {
function,
arguments,
} => {
write!(f, "{}(", function.lexeme())?;
for (i, argument) in arguments.iter().enumerate() {
if i > 0 {
write!(f, ", {}", argument)?;
} else {
write!(f, "{}", argument)?;
}
}
write!(f, ")")?;
}
Expression::Group { contents } => write!(f, "({})", contents)?,
}
Ok(())
}
}