eww/crates/simplexpr/src/ast.rs

use crate::dynval::DynVal;
use eww_shared_util::{Span, Spanned};
use itertools::Itertools;
use serde::{Deserialize, Serialize};

use eww_shared_util::VarName;

#[rustfmt::skip]
#[derive(Clone, PartialEq, Eq, Serialize, Deserialize, Debug, strum::EnumString, strum::Display)]
pub enum BinOp {
    #[strum(serialize = "+") ] Plus,
    #[strum(serialize = "-") ] Minus,
    #[strum(serialize = "*") ] Times,
    #[strum(serialize = "/") ] Div,
    #[strum(serialize = "%") ] Mod,
    #[strum(serialize = "==")] Equals,
    #[strum(serialize = "!=")] NotEquals,
    #[strum(serialize = "&&")] And,
    #[strum(serialize = "||")] Or,
    #[strum(serialize = ">=") ] GE,
    #[strum(serialize = "<=") ] LE,
    #[strum(serialize = ">") ] GT,
    #[strum(serialize = "<") ] LT,
    #[strum(serialize = "?:")] Elvis,
    #[strum(serialize = "=~")] RegexMatch,
}

#[derive(Clone, PartialEq, Eq, Serialize, Deserialize, Debug, strum::EnumString, strum::Display)]
pub enum UnaryOp {
    #[strum(serialize = "!")]
    Not,
    #[strum(serialize = "-")]
    Negative,
}

/// Differenciates between regular field access (`foo.bar`) and null-safe field access (`foo?.bar`)
#[derive(Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
pub enum AccessType {
    Normal,
    Safe,
}

#[derive(Clone, PartialEq, Eq, Serialize, Deserialize)]
pub enum SimplExpr {
    Literal(DynVal),
    JsonArray(Span, Vec<SimplExpr>),
    JsonObject(Span, Vec<(SimplExpr, SimplExpr)>),
    Concat(Span, Vec<SimplExpr>),
    VarRef(Span, VarName),
    BinOp(Span, Box<SimplExpr>, BinOp, Box<SimplExpr>),
    UnaryOp(Span, UnaryOp, Box<SimplExpr>),
    IfElse(Span, Box<SimplExpr>, Box<SimplExpr>, Box<SimplExpr>),
    JsonAccess(Span, AccessType, Box<SimplExpr>, Box<SimplExpr>),
    FunctionCall(Span, String, Vec<SimplExpr>),
}

impl std::fmt::Display for SimplExpr {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            SimplExpr::Literal(x) => write!(f, "\"{}\"", x),
            SimplExpr::Concat(_, elems) => {
                let text = elems
                    .iter()
                    .map(|x| match x {
                        SimplExpr::Literal(lit) => lit.to_string(),
                        other => format!("${{{}}}", other),
                    })
                    .join("");
                write!(f, "\"{}\"", text)
            }
            SimplExpr::VarRef(_, x) => write!(f, "{}", x),
            SimplExpr::BinOp(_, l, op, r) => write!(f, "({} {} {})", l, op, r),
            SimplExpr::UnaryOp(_, op, x) => write!(f, "{}{}", op, x),
            SimplExpr::IfElse(_, a, b, c) => write!(f, "({} ? {} : {})", a, b, c),
            SimplExpr::JsonAccess(_, AccessType::Normal, value, index) => write!(f, "{}[{}]", value, index),
            SimplExpr::JsonAccess(_, AccessType::Safe, value, index) => write!(f, "{}?.[{}]", value, index),
            SimplExpr::FunctionCall(_, function_name, args) => {
                write!(f, "{}({})", function_name, args.iter().join(", "))
            }
            SimplExpr::JsonArray(_, values) => write!(f, "[{}]", values.iter().join(", ")),
            SimplExpr::JsonObject(_, entries) => {
                write!(f, "{{{}}}", entries.iter().map(|(k, v)| format!("{}: {}", k, v)).join(", "))
            }
        }
    }
}
impl SimplExpr {
    pub fn literal(span: Span, s: String) -> Self {
        Self::Literal(DynVal(s, span))
    }

    /// Construct a synthetic simplexpr from a literal string, without adding any relevant span information (uses [`Span::DUMMY`])
    pub fn synth_string(s: impl Into<String>) -> Self {
        Self::Literal(DynVal(s.into(), Span::DUMMY))
    }

    /// Construct a synthetic simplexpr from a literal dynval, without adding any relevant span information (uses [`Span::DUMMY`])
    pub fn synth_literal<T: Into<DynVal>>(s: T) -> Self {
        Self::Literal(s.into())
    }

    pub fn var_ref(span: Span, n: impl Into<VarName>) -> Self {
        Self::VarRef(span, n.into())
    }

    pub fn references_var(&self, var: &VarName) -> bool {
        use SimplExpr::*;
        match self {
            Literal(_) => false,
            Concat(_, x) | FunctionCall(_, _, x) | JsonArray(_, x) => x.iter().any(|x| x.references_var(var)),
            JsonObject(_, x) => x.iter().any(|(k, v)| k.references_var(var) || v.references_var(var)),
            JsonAccess(_, _, a, b) | BinOp(_, a, _, b) => a.references_var(var) || b.references_var(var),
            UnaryOp(_, _, x) => x.references_var(var),
            IfElse(_, a, b, c) => a.references_var(var) || b.references_var(var) || c.references_var(var),
            VarRef(_, x) => x == var,
        }
    }

    pub fn collect_var_refs_into(&self, dest: &mut Vec<VarName>) {
        use SimplExpr::*;
        match self {
            VarRef(_, x) => dest.push(x.clone()),
            UnaryOp(_, _, x) => x.as_ref().collect_var_refs_into(dest),
            BinOp(_, a, _, b) | JsonAccess(_, _, a, b) => {
                a.as_ref().collect_var_refs_into(dest);
                b.as_ref().collect_var_refs_into(dest);
            }
            IfElse(_, a, b, c) => {
                a.as_ref().collect_var_refs_into(dest);
                b.as_ref().collect_var_refs_into(dest);
                c.as_ref().collect_var_refs_into(dest);
            }
            JsonArray(_, xs) | FunctionCall(_, _, xs) | Concat(_, xs) => xs.iter().for_each(|x| x.collect_var_refs_into(dest)),
            JsonObject(_, entries) => entries.iter().for_each(|(k, v)| {
                k.collect_var_refs_into(dest);
                v.collect_var_refs_into(dest);
            }),
            Literal(_) => {}
        };
    }

    pub fn collect_var_refs(&self) -> Vec<VarName> {
        let mut dest = Vec::new();
        self.collect_var_refs_into(&mut dest);
        dest
    }
}

impl Spanned for SimplExpr {
    fn span(&self) -> Span {
        match self {
            SimplExpr::Literal(x) => x.span(),
            SimplExpr::JsonArray(span, _) => *span,
            SimplExpr::JsonObject(span, _) => *span,
            SimplExpr::Concat(span, _) => *span,
            SimplExpr::VarRef(span, _) => *span,
            SimplExpr::BinOp(span, ..) => *span,
            SimplExpr::UnaryOp(span, ..) => *span,
            SimplExpr::IfElse(span, ..) => *span,
            SimplExpr::JsonAccess(span, ..) => *span,
            SimplExpr::FunctionCall(span, ..) => *span,
        }
    }
}

impl std::fmt::Debug for SimplExpr {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(f, "{}", self)
    }
}