pystencils.backend.ast.expressions.PsExpression

class pystencils.backend.ast.expressions.PsExpression(dtype=None)

Base class for all expressions.

Types: Each expression should be annotated with its type. Upon construction, the dtype property of most expression nodes is unset; only constant expressions, symbol expressions, and array accesses immediately inherit their type from their constant, symbol, or array, respectively.

The type assigned to an expression must never be const. Constness and mutability are properties of memory objects, not of expressions; they are verified by inspecting the memory objects referred to by an expression.

The canonical way to add types to newly constructed expressions is through the Typifier. It should be run at least once on any expression constructed by the backend.

The type annotations are used by various transformation passes to make decisions, e.g. in function materialization and intrinsic selection.

Attention

The structurally_equal <PsAstNode.structurally_equal> check currently does not take expression data types into account. This may change in the future.

Parameters:

dtype (PsType | None)

property dtype: PsType | None

Data type assigned to this expression

get_dtype()

Retrieve the data type assigned to this expression.

Raises:

PsInternalCompilerError – If this expression has no data type assigned

Return type:

PsType

clone()

Clone this expression.

Note

Subclasses of PsExpression should not override this method, but implement _clone_expr instead. That implementation shall call clone on any of its subexpressions, but does not need to fix the dtype property. The dtype is correctly applied by PsExpression.clone internally.

abstract _clone_expr()

Implementation of expression cloning.

Return type:

PsExpression