Enum Expression

pub enum Expression {
    Bubble(Metadata, Box<Expression>, Box<Expression>),
    Atomic(Metadata, Atom),
    Abs(Metadata, Box<Expression>),
    Sum(Metadata, Vec<Expression>),
    Product(Metadata, Vec<Expression>),
    Min(Metadata, Vec<Expression>),
    Max(Metadata, Vec<Expression>),
    Not(Metadata, Box<Expression>),
    Or(Metadata, Vec<Expression>),
    And(Metadata, Vec<Expression>),
    Imply(Metadata, Box<Expression>, Box<Expression>),
    Eq(Metadata, Box<Expression>, Box<Expression>),
    Neq(Metadata, Box<Expression>, Box<Expression>),
    Geq(Metadata, Box<Expression>, Box<Expression>),
    Leq(Metadata, Box<Expression>, Box<Expression>),
    Gt(Metadata, Box<Expression>, Box<Expression>),
    Lt(Metadata, Box<Expression>, Box<Expression>),
    SafeDiv(Metadata, Box<Expression>, Box<Expression>),
    UnsafeDiv(Metadata, Box<Expression>, Box<Expression>),
    SafeMod(Metadata, Box<Expression>, Box<Expression>),
    UnsafeMod(Metadata, Box<Expression>, Box<Expression>),
    Neg(Metadata, Box<Expression>),
    UnsafePow(Metadata, Box<Expression>, Box<Expression>),
    SafePow(Metadata, Box<Expression>, Box<Expression>),
    AllDiff(Metadata, Vec<Expression>),
    Minus(Metadata, Box<Expression>, Box<Expression>),
    FlatAbsEq(Metadata, Atom, Atom),
    FlatSumGeq(Metadata, Vec<Atom>, Atom),
    FlatSumLeq(Metadata, Vec<Atom>, Atom),
    FlatIneq(Metadata, Atom, Atom, Literal),
    FlatWatchedLiteral(Metadata, Name, Literal),
    FlatWeightedSumLeq(Metadata, Vec<Literal>, Vec<Atom>, Atom),
    FlatWeightedSumGeq(Metadata, Vec<Literal>, Vec<Atom>, Atom),
    FlatMinusEq(Metadata, Atom, Atom),
    FlatProductEq(Metadata, Atom, Atom, Atom),
    MinionDivEqUndefZero(Metadata, Atom, Atom, Atom),
    MinionModuloEqUndefZero(Metadata, Atom, Atom, Atom),
    MinionPow(Metadata, Atom, Atom, Atom),
    MinionReify(Metadata, Box<Expression>, Atom),
    MinionReifyImply(Metadata, Box<Expression>, Atom),
    AuxDeclaration(Metadata, Name, Box<Expression>),
}

Represents different types of expressions used to define rules and constraints in the model.

The Expression enum includes operations, constants, and variable references used to build rules and conditions for the model.

Compatability

Minion

• AuxDeclaration
• FlatAbsEq
• FlatIneq
• FlatMinusEq
• FlatProductEq
• FlatSumGeq
• FlatSumLeq
• FlatWatchedLiteral
• MinionDivEqUndefZero
• MinionModuloEqUndefZero
• MinionReify
• MinionReifyImply

JsonInput

• Abs
• AllDiff
• And
• Eq
• Geq
• Gt
• Imply
• Leq
• Lt
• Max
• Min
• Minus
• Neg
• Neq
• Not
• Or
• Product
• Sum
• UnsafeDiv
• UnsafeMod
• UnsafePow

SAT

• And
• Not
• Or

Variants

Bubble(Metadata, Box<Expression>, Box<Expression>)

An expression representing “A is valid as long as B is true” Turns into a conjunction when it reaches a boolean context

Atomic(Metadata, Atom)

Abs(Metadata, Box<Expression>)

|x| - absolute value of x Supported by: JsonInput.

Sum(Metadata, Vec<Expression>)

Supported by: JsonInput.

Product(Metadata, Vec<Expression>)

Supported by: JsonInput.

Min(Metadata, Vec<Expression>)

Supported by: JsonInput.

Max(Metadata, Vec<Expression>)

Supported by: JsonInput.

Not(Metadata, Box<Expression>)

Supported by: JsonInput, SAT.

Or(Metadata, Vec<Expression>)

Supported by: JsonInput, SAT.

And(Metadata, Vec<Expression>)

Supported by: JsonInput, SAT.

Imply(Metadata, Box<Expression>, Box<Expression>)

Ensures that a->b (material implication). Supported by: JsonInput.

Eq(Metadata, Box<Expression>, Box<Expression>)

Supported by: JsonInput.

Neq(Metadata, Box<Expression>, Box<Expression>)

Supported by: JsonInput.

Geq(Metadata, Box<Expression>, Box<Expression>)

Supported by: JsonInput.

Leq(Metadata, Box<Expression>, Box<Expression>)

Supported by: JsonInput.

Gt(Metadata, Box<Expression>, Box<Expression>)

Supported by: JsonInput.

Lt(Metadata, Box<Expression>, Box<Expression>)

Supported by: JsonInput.

SafeDiv(Metadata, Box<Expression>, Box<Expression>)

Division after preventing division by zero, usually with a bubble

UnsafeDiv(Metadata, Box<Expression>, Box<Expression>)

Division with a possibly undefined value (division by 0) Supported by: JsonInput.

SafeMod(Metadata, Box<Expression>, Box<Expression>)

Modulo after preventing mod 0, usually with a bubble

UnsafeMod(Metadata, Box<Expression>, Box<Expression>)

Modulo with a possibly undefined value (mod 0) Supported by: JsonInput.

Neg(Metadata, Box<Expression>)

Negation: -x Supported by: JsonInput.

UnsafePow(Metadata, Box<Expression>, Box<Expression>)

Unsafe powerx**y (possibly undefined)

Defined when (X!=0 \/ Y!=0) /\ Y>=0 Supported by: JsonInput.

SafePow(Metadata, Box<Expression>, Box<Expression>)

UnsafePow after preventing undefinedness

AllDiff(Metadata, Vec<Expression>)

Supported by: JsonInput.

Minus(Metadata, Box<Expression>, Box<Expression>)

Binary subtraction operator

This is a parser-level construct, and is immediately normalised to Sum([a,-b]). Supported by: JsonInput.

FlatAbsEq(Metadata, Atom, Atom)

Ensures that x=|y| i.e. x is the absolute value of y.

Low-level Minion constraint.

See also

• Minion documentation Supported by: Minion.

FlatSumGeq(Metadata, Vec<Atom>, Atom)

Ensures that sum(vec) >= x.

Low-level Minion constraint.

See also

• Minion documentation Supported by: Minion.

FlatSumLeq(Metadata, Vec<Atom>, Atom)

Ensures that sum(vec) <= x.

Low-level Minion constraint.

See also

• Minion documentation Supported by: Minion.

FlatIneq(Metadata, Atom, Atom, Literal)

ineq(x,y,k) ensures that x <= y + k.

Low-level Minion constraint.

See also

• Minion documentation Supported by: Minion.

FlatWatchedLiteral(Metadata, Name, Literal)

w-literal(x,k) ensures that x == k, where x is a variable and k a constant.

Low-level Minion constraint.

This is a low-level Minion constraint and you should probably use Eq instead. The main use of w-literal is to convert boolean variables to constraints so that they can be used inside watched-and and watched-or.

See also

• Minion documentation
• rules::minion::boolean_literal_to_wliteral. Supported by: Minion.

FlatWeightedSumLeq(Metadata, Vec<Literal>, Vec<Atom>, Atom)

weightedsumleq(cs,xs,total) ensures that cs.xs <= total, where cs.xs is the scalar dot product of cs and xs.

Low-level Minion constraint.

Represents a weighted sum of the form ax + by + cz + ...

See also

• Minion documentation

FlatWeightedSumGeq(Metadata, Vec<Literal>, Vec<Atom>, Atom)

weightedsumgeq(cs,xs,total) ensures that cs.xs >= total, where cs.xs is the scalar dot product of cs and xs.

Low-level Minion constraint.

Represents a weighted sum of the form ax + by + cz + ...

See also

• Minion documentation

FlatMinusEq(Metadata, Atom, Atom)

Ensures that x =-y, where x and y are atoms.

Low-level Minion constraint.

See also

• Minion documentation Supported by: Minion.

FlatProductEq(Metadata, Atom, Atom, Atom)

Ensures that x*y=z.

Low-level Minion constraint.

See also

• Minion documentation Supported by: Minion.

MinionDivEqUndefZero(Metadata, Atom, Atom, Atom)

Ensures that floor(x/y)=z. Always true when y=0.

Low-level Minion constraint.

See also

• Minion documentation Supported by: Minion.

MinionModuloEqUndefZero(Metadata, Atom, Atom, Atom)

Ensures that x%y=z. Always true when y=0.

Low-level Minion constraint.

See also

• Minion documentation Supported by: Minion.

MinionPow(Metadata, Atom, Atom, Atom)

Ensures that x**y = z.

Low-level Minion constraint.

This constraint is false when y<0 except for 1**y=1 and (-1)**y=z (where z is 1 if y is odd and z is -1 if y is even).

See also

• Github comment about pow semantics
• Minion documentation

MinionReify(Metadata, Box<Expression>, Atom)

reify(constraint,r) ensures that r=1 iff constraint is satisfied, where r is a 0/1 variable.

Low-level Minion constraint.

See also

• Minion documentation Supported by: Minion.

MinionReifyImply(Metadata, Box<Expression>, Atom)

reifyimply(constraint,r) ensures that r->constraint, where r is a 0/1 variable. variable.

Low-level Minion constraint.

See also

• Minion documentation Supported by: Minion.

AuxDeclaration(Metadata, Name, Box<Expression>)

Declaration of an auxiliary variable.

As with Savile Row, we semantically distinguish this from Eq. Supported by: Minion.

Implementations

impl Expression

pub fn domain_of(&self, syms: &SymbolTable) -> Option<Domain>

Returns the possible values of the expression, recursing to leaf expressions

pub fn get_meta(&self) -> Metadata

pub fn set_meta(&self, meta: Metadata)

pub fn is_safe(&self) -> bool

Checks whether this expression is safe.

An expression is unsafe if can be undefined, or if any of its children can be undefined.

Unsafe expressions are (typically) prefixed with Unsafe in our AST, and can be made safe through the use of bubble rules.

pub fn return_type(&self) -> Option<ReturnType>

pub fn is_clean(&self) -> bool

pub fn set_clean(&mut self, bool_value: bool)

pub fn is_associative_commutative_operator(&self) -> bool

True if the expression is an associative and commutative operator

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

True iff self and other are both atomic and identical.

This method is useful to cheaply check equivalence. Assuming CSE is enabled, any unifiable expressions will be rewritten to a common variable. This is much cheaper than checking the entire subtrees of self and other.

Trait Implementations

impl Biplate<Atom> for Expression

fn biplate(&self) -> (Tree<Atom>, Box<dyn Fn(Tree<Atom>) -> Expression>)

Definition of a Biplate.

fn with_children_bi(&self, children: VecDeque<To>) -> Self

Reconstructs the node with the given children.

fn descend_bi(&self, op: Arc<dyn Fn(To) -> To>) -> Self

Biplate variant of [Uniplate::descend]

fn universe_bi(&self) -> VecDeque<To>

Gets all children of a node, including itself and all children.

fn children_bi(&self) -> VecDeque<To>

Returns the children of a type. If to == from then it returns the original element (in contrast to children).

fn transform_bi(&self, op: Arc<dyn Fn(To) -> To>) -> Self

Applies the given function to all nodes bottom up.

fn holes_bi(&self) -> impl Iterator<Item = (To, Arc<dyn Fn(To) -> Self>)>

Returns an iterator over all direct children of the input, paired with a function that “fills the hole” where the child was with a new value.

fn contexts_bi(&self) -> impl Iterator<Item = (To, Arc<dyn Fn(To) -> Self>)>

Returns an iterator over the universe of the input, paired with a function that “fills the hole” where the child was with a new value.

impl Biplate<Expression> for Atom

fn biplate(&self) -> (Tree<Expression>, Box<dyn Fn(Tree<Expression>) -> Atom>)

Definition of a Biplate.

fn with_children_bi(&self, children: VecDeque<To>) -> Self

Reconstructs the node with the given children.

fn descend_bi(&self, op: Arc<dyn Fn(To) -> To>) -> Self

Biplate variant of [Uniplate::descend]

fn universe_bi(&self) -> VecDeque<To>

Gets all children of a node, including itself and all children.

fn children_bi(&self) -> VecDeque<To>

Returns the children of a type. If to == from then it returns the original element (in contrast to children).

fn transform_bi(&self, op: Arc<dyn Fn(To) -> To>) -> Self

Applies the given function to all nodes bottom up.

fn holes_bi(&self) -> impl Iterator<Item = (To, Arc<dyn Fn(To) -> Self>)>

Returns an iterator over all direct children of the input, paired with a function that “fills the hole” where the child was with a new value.

fn contexts_bi(&self) -> impl Iterator<Item = (To, Arc<dyn Fn(To) -> Self>)>

Returns an iterator over the universe of the input, paired with a function that “fills the hole” where the child was with a new value.

impl Biplate<Expression> for Expression

fn biplate( &self, ) -> (Tree<Expression>, Box<dyn Fn(Tree<Expression>) -> Expression>)

Definition of a Biplate.

fn with_children_bi(&self, children: VecDeque<To>) -> Self

Reconstructs the node with the given children.

fn descend_bi(&self, op: Arc<dyn Fn(To) -> To>) -> Self

Biplate variant of [Uniplate::descend]

fn universe_bi(&self) -> VecDeque<To>

Gets all children of a node, including itself and all children.

fn children_bi(&self) -> VecDeque<To>

Returns the children of a type. If to == from then it returns the original element (in contrast to children).

fn transform_bi(&self, op: Arc<dyn Fn(To) -> To>) -> Self

Applies the given function to all nodes bottom up.

fn holes_bi(&self) -> impl Iterator<Item = (To, Arc<dyn Fn(To) -> Self>)>

Returns an iterator over all direct children of the input, paired with a function that “fills the hole” where the child was with a new value.

fn contexts_bi(&self) -> impl Iterator<Item = (To, Arc<dyn Fn(To) -> Self>)>

Returns an iterator over the universe of the input, paired with a function that “fills the hole” where the child was with a new value.

impl Biplate<Literal> for Expression

fn biplate(&self) -> (Tree<Literal>, Box<dyn Fn(Tree<Literal>) -> Expression>)

Definition of a Biplate.

fn with_children_bi(&self, children: VecDeque<To>) -> Self

Reconstructs the node with the given children.

fn descend_bi(&self, op: Arc<dyn Fn(To) -> To>) -> Self

Biplate variant of [Uniplate::descend]

fn universe_bi(&self) -> VecDeque<To>

Gets all children of a node, including itself and all children.

fn children_bi(&self) -> VecDeque<To>

Returns the children of a type. If to == from then it returns the original element (in contrast to children).

fn transform_bi(&self, op: Arc<dyn Fn(To) -> To>) -> Self

Applies the given function to all nodes bottom up.

fn holes_bi(&self) -> impl Iterator<Item = (To, Arc<dyn Fn(To) -> Self>)>

Returns an iterator over all direct children of the input, paired with a function that “fills the hole” where the child was with a new value.

fn contexts_bi(&self) -> impl Iterator<Item = (To, Arc<dyn Fn(To) -> Self>)>

Returns an iterator over the universe of the input, paired with a function that “fills the hole” where the child was with a new value.

impl Biplate<Metadata> for Expression

fn biplate(&self) -> (Tree<Metadata>, Box<dyn Fn(Tree<Metadata>) -> Expression>)

Definition of a Biplate.

fn with_children_bi(&self, children: VecDeque<To>) -> Self

Reconstructs the node with the given children.

fn descend_bi(&self, op: Arc<dyn Fn(To) -> To>) -> Self

Biplate variant of [Uniplate::descend]

fn universe_bi(&self) -> VecDeque<To>

Gets all children of a node, including itself and all children.

fn children_bi(&self) -> VecDeque<To>

Returns the children of a type. If to == from then it returns the original element (in contrast to children).

fn transform_bi(&self, op: Arc<dyn Fn(To) -> To>) -> Self

Applies the given function to all nodes bottom up.

fn holes_bi(&self) -> impl Iterator<Item = (To, Arc<dyn Fn(To) -> Self>)>

Returns an iterator over all direct children of the input, paired with a function that “fills the hole” where the child was with a new value.

fn contexts_bi(&self) -> impl Iterator<Item = (To, Arc<dyn Fn(To) -> Self>)>

Returns an iterator over the universe of the input, paired with a function that “fills the hole” where the child was with a new value.

impl Biplate<Name> for Expression

fn biplate(&self) -> (Tree<Name>, Box<dyn Fn(Tree<Name>) -> Expression>)

Definition of a Biplate.

fn with_children_bi(&self, children: VecDeque<To>) -> Self

Reconstructs the node with the given children.

fn descend_bi(&self, op: Arc<dyn Fn(To) -> To>) -> Self

Biplate variant of [Uniplate::descend]

fn universe_bi(&self) -> VecDeque<To>

Gets all children of a node, including itself and all children.

fn children_bi(&self) -> VecDeque<To>

Returns the children of a type. If to == from then it returns the original element (in contrast to children).

fn transform_bi(&self, op: Arc<dyn Fn(To) -> To>) -> Self

Applies the given function to all nodes bottom up.

fn holes_bi(&self) -> impl Iterator<Item = (To, Arc<dyn Fn(To) -> Self>)>

Returns an iterator over all direct children of the input, paired with a function that “fills the hole” where the child was with a new value.

fn contexts_bi(&self) -> impl Iterator<Item = (To, Arc<dyn Fn(To) -> Self>)>

Returns an iterator over the universe of the input, paired with a function that “fills the hole” where the child was with a new value.

impl Biplate<Vec<Expression>> for Expression

fn biplate( &self, ) -> (Tree<Vec<Expression>>, Box<dyn Fn(Tree<Vec<Expression>>) -> Expression>)

Definition of a Biplate.

fn with_children_bi(&self, children: VecDeque<To>) -> Self

Reconstructs the node with the given children.

fn descend_bi(&self, op: Arc<dyn Fn(To) -> To>) -> Self

Biplate variant of [Uniplate::descend]

fn universe_bi(&self) -> VecDeque<To>

Gets all children of a node, including itself and all children.

fn children_bi(&self) -> VecDeque<To>

Returns the children of a type. If to == from then it returns the original element (in contrast to children).

fn transform_bi(&self, op: Arc<dyn Fn(To) -> To>) -> Self

Applies the given function to all nodes bottom up.

fn holes_bi(&self) -> impl Iterator<Item = (To, Arc<dyn Fn(To) -> Self>)>

Returns an iterator over all direct children of the input, paired with a function that “fills the hole” where the child was with a new value.

fn contexts_bi(&self) -> impl Iterator<Item = (To, Arc<dyn Fn(To) -> Self>)>

Returns an iterator over the universe of the input, paired with a function that “fills the hole” where the child was with a new value.

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 Display for Expression

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

Formats the value using the given formatter.

impl From<Atom> for Expression

fn from(value: Atom) -> 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<i32> for Expression

fn from(i: i32) -> Self

Converts to this type from the input type.

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<'a> TryFrom<&'a Expression> for &'a Atom

type Error = &'static str

The type returned in the event of a conversion error.

fn try_from(value: &'a Expression) -> Result<Self, Self::Error>

Performs the conversion.

impl TryFrom<Expression> for Atom

type Error = &'static str

The type returned in the event of a conversion error.

fn try_from(value: Expression) -> Result<Self, Self::Error>

Performs the conversion.

impl Uniplate for Expression

fn uniplate( &self, ) -> (Tree<Expression>, Box<dyn Fn(Tree<Expression>) -> Expression>)

Definition of a Uniplate.

fn descend(&self, op: Arc<dyn Fn(Self) -> Self>) -> Self

Applies a function to all direct children of this

fn universe(&self) -> VecDeque<Self>

Gets all children of a node, including itself and all children.

fn children(&self) -> VecDeque<Self>

Gets the direct children (maximal substructures) of a node.

fn with_children(&self, children: VecDeque<Self>) -> Self

Reconstructs the node with the given children.

fn transform(&self, f: Arc<dyn Fn(Self) -> Self>) -> Self

Applies the given function to all nodes bottom up.

fn rewrite(&self, f: Arc<dyn Fn(Self) -> Option<Self>>) -> Self

Rewrites by applying a rule everywhere it can.

fn cata<T>(&self, op: Arc<dyn Fn(Self, VecDeque<T>) -> T>) -> T

Performs a fold-like computation on each value.

fn holes(&self) -> impl Iterator<Item = (Self, Arc<dyn Fn(Self) -> Self>)>

Returns an iterator over all direct children of the input, paired with a function that “fills the hole” where the child was with a new value.

fn contexts(&self) -> impl Iterator<Item = (Self, Arc<dyn Fn(Self) -> Self>)>

Returns an iterator over the universe of the input, paired with a function that “fills the hole” where the child was with a new value.

impl Eq for Expression

impl StructuralPartialEq for Expression