expr

Source: crates/lvcs-action/src/expr.rs.

/// A number, compared and ordered by its bits so the canonical form is
/// totally ordered.
#[derive(Debug, Clone, Copy, Serialize, Deserialize)]
#[serde(transparent)]
pub struct Num(pub f64);

/// A value: GitHub's null, booleans, numbers, strings, arrays, and objects,
/// each object's keys sorted.
#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Serialize, Deserialize)]
#[serde(rename_all = "snake_case")]
pub enum Value {
    /// `null`.
    Null,
    /// A boolean.
    Bool(bool),
    /// A number.
    Num(Num),
    /// A string.
    Str(String),
    /// An array.
    Array(Vec<Value>),
    /// An object, its keys sorted.
    Object(BTreeMap<String, Value>),
}

/// A function GitHub's expressions call.
#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Serialize, Deserialize)]
#[serde(rename_all = "snake_case")]
pub enum Func {
    /// `contains(haystack, needle)`.
    Contains,
    /// `startsWith(text, prefix)`.
    StartsWith,
    /// `endsWith(text, suffix)`.
    EndsWith,
    /// `format(spec, args...)`.
    Format,
    /// `join(items, separator?)`.
    Join,
    /// `toJSON(value)`.
    ToJson,
    /// `fromJSON(text)`.
    FromJson,
    /// `hashFiles(globs...)`: the shell's digest of the matched files.
    HashFiles,
    /// `case(pred, value, ..., default)`.
    Case,
    /// `success()`.
    Success,
    /// `always()`.
    Always,
    /// `cancelled()`.
    Cancelled,
    /// `failure()`.
    Failure,
}

/// A binary operator.
#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Serialize, Deserialize)]
#[serde(rename_all = "snake_case")]
pub enum BinOp {
    /// `&&`, returning the left value when it is falsy, else the right.
    And,
    /// `||`, returning the left value when it is truthy, else the right.
    Or,
    /// `==`.
    Eq,
    /// `!=`.
    Neq,
    /// `<`.
    Lt,
    /// `<=`.
    Le,
    /// `>`.
    Gt,
    /// `>=`.
    Ge,
}

/// One access after a path's head.
#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Serialize, Deserialize)]
#[serde(rename_all = "snake_case")]
pub enum Seg {
    /// `.name`, looked up case-insensitively.
    Prop(String),
    /// `[expr]`.
    Index(Box<Ast>),
    /// `.*` or `[*]`: the object filter.
    Star,
}

/// What a path starts from.
#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Serialize, Deserialize)]
#[serde(rename_all = "snake_case")]
pub enum Head {
    /// A context, by its lowercase name.
    Context(String),
    /// A call or a parenthesized expression.
    Expr(Box<Ast>),
}

/// An expression's tree.
#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Serialize, Deserialize)]
#[serde(rename_all = "snake_case")]
pub enum Ast {
    /// A value.
    Lit(Value),
    /// A context read, or accesses into an expression's value.
    Path {
        /// What it starts from.
        head: Head,
        /// Its accesses, in order.
        segs: Vec<Seg>,
    },
    /// A function call.
    Call {
        /// The function.
        func: Func,
        /// Its arguments.
        args: Vec<Ast>,
    },
    /// A binary expression.
    Bin {
        /// The operator.
        op: BinOp,
        /// The left side.
        lhs: Box<Ast>,
        /// The right side.
        rhs: Box<Ast>,
    },
    /// `!expr`.
    Not(Box<Ast>),
}