Enum Expression

#[non_exhaustive]
pub enum Expression {
    Null,
    Bool(bool),
    Number(Number),
    String(String),
    Array(Vec<Expression>),
    Object(Object<ObjectKey, Expression>),
    TemplateExpr(Box<TemplateExpr>),
    Variable(Variable),
    Traversal(Box<Traversal>),
    FuncCall(Box<FuncCall>),
    Parenthesis(Box<Expression>),
    Conditional(Box<Conditional>),
    Operation(Box<Operation>),
    ForExpr(Box<ForExpr>),
}

A type representing the expression sub-language. It is used in HCL attributes to specify values and in HCL templates.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

Null

Represents a null value.

Bool(bool)

Represents a boolean.

Number(Number)

Represents a number, either integer or float.

String(String)

Represents a string that does not contain any template interpolations or template directives.

Array(Vec<Expression>)

Represents array.

Object(Object<ObjectKey, Expression>)

Represents an object.

TemplateExpr(Box<TemplateExpr>)

A quoted string or heredoc that embeds a program written in the template sub-language.

Variable(Variable)

Represents a variable name identifier.

Traversal(Box<Traversal>)

Represents an attribute or element traversal.

FuncCall(Box<FuncCall>)

Represents a function call.

Parenthesis(Box<Expression>)

Represents a sub-expression that is wrapped in parenthesis.

Conditional(Box<Conditional>)

A conditional operator which selects one of two rexpressions based on the outcome of a boolean expression.

Operation(Box<Operation>)

An operation which applies a particular operator to either one or two expression terms.

ForExpr(Box<ForExpr>)

A construct for constructing a collection by projecting the items from another collection.

Trait Implementations

impl Clone for Expression

fn clone(&self) -> Expression

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Expression

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for Expression

fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>

where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<'de> Deserializer<'de> for Expression

type Error = Error

The error type that can be returned if some error occurs during deserialization.

fn deserialize_i8<V>(self, visitor: V) -> Result<V::Value, Self::Error>

where V: Visitor<'de>,

Hint that the Deserialize type is expecting an i8 value.

fn deserialize_i16<V>(self, visitor: V) -> Result<V::Value, Self::Error>

where V: Visitor<'de>,

Hint that the Deserialize type is expecting an i16 value.

fn deserialize_i32<V>(self, visitor: V) -> Result<V::Value, Self::Error>

where V: Visitor<'de>,

Hint that the Deserialize type is expecting an i32 value.

fn deserialize_i64<V>(self, visitor: V) -> Result<V::Value, Self::Error>

where V: Visitor<'de>,

Hint that the Deserialize type is expecting an i64 value.

fn deserialize_i128<V>(self, visitor: V) -> Result<V::Value, Self::Error>

where V: Visitor<'de>,

Hint that the Deserialize type is expecting an i128 value.

fn deserialize_u8<V>(self, visitor: V) -> Result<V::Value, Self::Error>

where V: Visitor<'de>,

Hint that the Deserialize type is expecting a u8 value.

fn deserialize_u16<V>(self, visitor: V) -> Result<V::Value, Self::Error>

where V: Visitor<'de>,

Hint that the Deserialize type is expecting a u16 value.

fn deserialize_u32<V>(self, visitor: V) -> Result<V::Value, Self::Error>

where V: Visitor<'de>,

Hint that the Deserialize type is expecting a u32 value.

fn deserialize_u64<V>(self, visitor: V) -> Result<V::Value, Self::Error>

where V: Visitor<'de>,

Hint that the Deserialize type is expecting a u64 value.

fn deserialize_u128<V>(self, visitor: V) -> Result<V::Value, Self::Error>

where V: Visitor<'de>,

Hint that the Deserialize type is expecting an u128 value.

fn deserialize_f32<V>(self, visitor: V) -> Result<V::Value, Self::Error>

where V: Visitor<'de>,

Hint that the Deserialize type is expecting a f32 value.

fn deserialize_f64<V>(self, visitor: V) -> Result<V::Value, Self::Error>

where V: Visitor<'de>,

Hint that the Deserialize type is expecting a f64 value.

fn deserialize_any<V>(self, visitor: V) -> Result<V::Value, Self::Error>

where V: Visitor<'de>,

Require the Deserializer to figure out how to drive the visitor based on what data type is in the input.

fn deserialize_option<V>(self, visitor: V) -> Result<V::Value, Self::Error>

where V: Visitor<'de>,

Hint that the Deserialize type is expecting an optional value.

fn deserialize_enum<V>( self, name: &'static str, _variants: &'static [&'static str], visitor: V, ) -> Result<V::Value, Self::Error>

where V: Visitor<'de>,

Hint that the Deserialize type is expecting an enum value with a particular name and possible variants.

fn deserialize_newtype_struct<V>( self, _name: &'static str, visitor: V, ) -> Result<V::Value, Self::Error>

where V: Visitor<'de>,

Hint that the Deserialize type is expecting a newtype struct with a particular name.

fn deserialize_bool<V>(self, visitor: V) -> Result<V::Value, Self::Error>

where V: Visitor<'de>,

Hint that the Deserialize type is expecting a bool value.

fn deserialize_char<V>(self, visitor: V) -> Result<V::Value, Self::Error>

where V: Visitor<'de>,

Hint that the Deserialize type is expecting a char value.

fn deserialize_str<V>(self, visitor: V) -> Result<V::Value, Self::Error>

where V: Visitor<'de>,

Hint that the Deserialize type is expecting a string value and does not benefit from taking ownership of buffered data owned by the Deserializer.

fn deserialize_string<V>(self, visitor: V) -> Result<V::Value, Self::Error>

where V: Visitor<'de>,

Hint that the Deserialize type is expecting a string value and would benefit from taking ownership of buffered data owned by the Deserializer.

fn deserialize_bytes<V>(self, visitor: V) -> Result<V::Value, Self::Error>

where V: Visitor<'de>,

Hint that the Deserialize type is expecting a byte array and does not benefit from taking ownership of buffered data owned by the Deserializer.

fn deserialize_byte_buf<V>(self, visitor: V) -> Result<V::Value, Self::Error>

where V: Visitor<'de>,

Hint that the Deserialize type is expecting a byte array and would benefit from taking ownership of buffered data owned by the Deserializer.

fn deserialize_unit<V>(self, visitor: V) -> Result<V::Value, Self::Error>

where V: Visitor<'de>,

Hint that the Deserialize type is expecting a unit value.

fn deserialize_unit_struct<V>( self, _name: &'static str, visitor: V, ) -> Result<V::Value, Self::Error>

where V: Visitor<'de>,

Hint that the Deserialize type is expecting a unit struct with a particular name.

fn deserialize_seq<V>(self, visitor: V) -> Result<V::Value, Self::Error>

where V: Visitor<'de>,

Hint that the Deserialize type is expecting a sequence of values.

fn deserialize_tuple<V>( self, _len: usize, visitor: V, ) -> Result<V::Value, Self::Error>

where V: Visitor<'de>,

Hint that the Deserialize type is expecting a sequence of values and knows how many values there are without looking at the serialized data.

fn deserialize_tuple_struct<V>( self, _name: &'static str, _len: usize, visitor: V, ) -> Result<V::Value, Self::Error>

where V: Visitor<'de>,

Hint that the Deserialize type is expecting a tuple struct with a particular name and number of fields.

fn deserialize_map<V>(self, visitor: V) -> Result<V::Value, Self::Error>

where V: Visitor<'de>,

Hint that the Deserialize type is expecting a map of key-value pairs.

fn deserialize_struct<V>( self, _name: &'static str, _fields: &'static [&'static str], visitor: V, ) -> Result<V::Value, Self::Error>

where V: Visitor<'de>,

Hint that the Deserialize type is expecting a struct with a particular name and fields.

fn deserialize_identifier<V>(self, visitor: V) -> Result<V::Value, Self::Error>

where V: Visitor<'de>,

Hint that the Deserialize type is expecting the name of a struct field or the discriminant of an enum variant.

fn deserialize_ignored_any<V>(self, visitor: V) -> Result<V::Value, Self::Error>

where V: Visitor<'de>,

Hint that the Deserialize type needs to deserialize a value whose type doesn’t matter because it is ignored.

fn is_human_readable(&self) -> bool

Determine whether Deserialize implementations should expect to deserialize their human-readable form.

impl Display for Expression

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'de> EnumAccess<'de> for Expression

type Error = Error

The error type that can be returned if some error occurs during deserialization.

type Variant = Expression

The Visitor that will be used to deserialize the content of the enum variant.

fn variant_seed<T>( self, seed: T, ) -> Result<(T::Value, Self::Variant), Self::Error>

where T: DeserializeSeed<'de>,

variant is called to identify which variant to deserialize.

fn variant<V>(self) -> Result<(V, Self::Variant), Self::Error>

where V: Deserialize<'de>,

variant is called to identify which variant to deserialize.

impl Evaluate for Expression

type Output = Value

The type that is returned by evaluate on success.

fn evaluate(&self, ctx: &Context<'_>) -> EvalResult<Self::Output>

Recursively evaluates all HCL templates and expressions in the implementing type using the variables and functions declared in the Context.

fn evaluate_in_place(&mut self, ctx: &Context<'_>) -> EvalResult<(), Errors>

Recursively tries to evaluate all nested expressions in place.

impl Format for Expression

fn format<W>(&self, fmt: &mut Formatter<'_, W>) -> Result<()>

where W: Write,

Formats a HCL structure using a formatter and writes the result to the provided writer.

fn format_vec<W>(&self, fmt: &mut Formatter<'_, W>) -> Result<Vec<u8>>

where W: Write + AsMut<Vec<u8>>,

Formats a HCL structure using a formatter and returns the result as a Vec<u8>.

fn format_string<W>(&self, fmt: &mut Formatter<'_, W>) -> Result<String>

where W: Write + AsMut<Vec<u8>>,

Formats a HCL structure using a formatter and returns the result as a String.

impl<'a, T: Clone + Into<Expression>> From<&'a [T]> for Expression

fn from(f: &'a [T]) -> Self

Converts to this type from the input type.

impl From<&str> for Expression

fn from(s: &str) -> Self

Converts to this type from the input type.

impl From<()> for Expression

fn from((): ()) -> Self

Converts to this type from the input type.

impl From<BinaryOp> for Expression

fn from(op: BinaryOp) -> Self

Converts to this type from the input type.

impl From<Conditional> for Expression

fn from(cond: Conditional) -> Self

Converts to this type from the input type.

impl<'a> From<Cow<'a, str>> for Expression

fn from(s: Cow<'a, str>) -> Self

Converts to this type from the input type.

impl From<Expression> for Expression

fn from(value: Expression) -> Self

Converts to this type from the input type.

impl From<Expression> for Expression

fn from(value: Expression) -> Self

Converts to this type from the input type.

impl From<Expression> for ObjectValue

fn from(value: Expression) -> Self

Converts to this type from the input type.

impl From<Expression> for TraversalOperator

fn from(value: Expression) -> TraversalOperator

Converts to this type from the input type.

impl From<Expression> for Value

fn from(expr: Expression) -> Self

Converts to this type from the input type.

impl From<ForExpr> for Expression

fn from(expr: ForExpr) -> Self

Converts to this type from the input type.

impl From<FuncCall> for Expression

fn from(func_call: FuncCall) -> Self

Converts to this type from the input type.

impl From<Heredoc> for Expression

fn from(heredoc: Heredoc) -> Self

Converts to this type from the input type.

impl From<Number> for Expression

fn from(num: Number) -> Self

Converts to this type from the input type.

impl From<ObjectValue> for Expression

fn from(value: ObjectValue) -> Self

Converts to this type from the input type.

impl From<Operation> for Expression

fn from(op: Operation) -> Self

Converts to this type from the input type.

impl From<String> for Expression

fn from(s: String) -> Self

Converts to this type from the input type.

impl<T> From<T> for Expression

where T: IntoJsonSpec,

fn from(value: T) -> Expression

Converts to this type from the input type.

impl From<TemplateExpr> for Expression

fn from(expr: TemplateExpr) -> Self

Converts to this type from the input type.

impl From<Traversal> for Expression

fn from(traversal: Traversal) -> Self

Converts to this type from the input type.

impl From<UnaryOp> for Expression

fn from(op: UnaryOp) -> Self

Converts to this type from the input type.

impl From<Value> for Expression

fn from(value: Value) -> Self

Converts to this type from the input type.

impl From<Variable> for Expression

fn from(variable: Variable) -> Self

Converts to this type from the input type.

impl<T: Into<Expression>> From<Vec<T>> for Expression

fn from(f: Vec<T>) -> Self

Converts to this type from the input type.

impl From<VecMap<ObjectKey, Expression>> for Expression

fn from(f: Object<ObjectKey, Expression>) -> Self

Converts to this type from the input type.

impl From<bool> for Expression

fn from(b: bool) -> Self

Converts to this type from the input type.

impl From<f32> for Expression

fn from(f: f32) -> Self

Converts to this type from the input type.

impl From<f64> for Expression

fn from(f: f64) -> Self

Converts to this type from the input type.

impl From<i16> for Expression

fn from(n: i16) -> Self

Converts to this type from the input type.

impl From<i32> for Expression

fn from(n: i32) -> Self

Converts to this type from the input type.

impl From<i64> for Expression

fn from(n: i64) -> Self

Converts to this type from the input type.

impl From<i8> for Expression

fn from(n: i8) -> Self

Converts to this type from the input type.

impl From<isize> for Expression

fn from(n: isize) -> Self

Converts to this type from the input type.

impl From<u16> for Expression

fn from(n: u16) -> Self

Converts to this type from the input type.

impl From<u32> for Expression

fn from(n: u32) -> Self

Converts to this type from the input type.

impl From<u64> for Expression

fn from(n: u64) -> Self

Converts to this type from the input type.

impl From<u8> for Expression

fn from(n: u8) -> Self

Converts to this type from the input type.

impl From<usize> for Expression

fn from(n: usize) -> Self

Converts to this type from the input type.

impl<K: Into<ObjectKey>, V: Into<Expression>> FromIterator<(K, V)> for Expression

fn from_iter<I: IntoIterator<Item = (K, V)>>(iter: I) -> Self

Creates a value from an iterator.

impl<T: Into<Expression>> FromIterator<T> for Expression

fn from_iter<I: IntoIterator<Item = T>>(iter: I) -> Self

Creates a value from an iterator.

impl<'de> IntoDeserializer<'de, Error> for Expression

type Deserializer = Expression

The type of the deserializer being converted into.

fn into_deserializer(self) -> Self::Deserializer

Convert this value into a deserializer.

impl PartialEq for Expression

fn eq(&self, other: &Expression) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for Expression

fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>

where S: Serializer,

Serialize this value into the given Serde serializer.

impl<'de> VariantAccess<'de> for Expression

type Error = Error

The error type that can be returned if some error occurs during deserialization. Must match the error type of our EnumAccess.

fn unit_variant(self) -> Result<(), Self::Error>

Called when deserializing a variant with no values.

fn newtype_variant_seed<T>(self, seed: T) -> Result<T::Value, Self::Error>

where T: DeserializeSeed<'de>,

Called when deserializing a variant with a single value.

fn tuple_variant<V>( self, _len: usize, visitor: V, ) -> Result<V::Value, Self::Error>

where V: Visitor<'de>,

Called when deserializing a tuple-like variant.

fn struct_variant<V>( self, _fields: &'static [&'static str], visitor: V, ) -> Result<V::Value, Self::Error>

where V: Visitor<'de>,

Called when deserializing a struct-like variant.

fn newtype_variant<T>(self) -> Result<T, Self::Error>

where T: Deserialize<'de>,

Called when deserializing a variant with a single value.

impl Eq for Expression

impl StructuralPartialEq for Expression