triqs.gfs.lazy_expressions.LazyExpr

class triqs.gfs.lazy_expressions.LazyExpr(*args)[source]

Bases: __aux

A node in a lazy expression tree.

Each node carries a tag and a list of childs. Tags are:

"T" — terminal; childs[0] is the wrapped value (descriptor, scalar, …).
"+", "-", "*", "/" — binary arithmetic; the two children are themselves LazyExpr nodes.
"F" — function application; childs[0] is a terminal wrapping the callable, the remaining children are its arguments.

Operator overloads on the parent __aux build these trees from Python expressions (a + b, f(a, b), …).

Parameters:

*args

Single argument — if it is a LazyExpr its tag and childs are aliased; otherwise the argument is wrapped as a terminal (tag = 'T').
Two or more arguments — first is interpreted as the tag, the rest as childs.

Attributes

tag	(str) Node kind.
childs	(list) Child nodes (or wrapped payload for terminals).

Methods

`copy`()	Shallow copy of this node (children are shared).
`get_terminal`()	Wrapped payload, or `None` if this node is not a leaf.
`is_terminal`()	Whether this node is a leaf node.
`set_from`(y)	In-place assignment: `self` is rewritten to match `y`.