Documentation
¶
Overview ¶
Package inspector provides helper functions for traversal over the syntax trees of a package, including node filtering by type, and materialization of the traversal stack.
During construction, the inspector does a complete traversal and builds a list of push/pop events and their node type. Subsequent method calls that request a traversal scan this list, rather than walk the AST, and perform type filtering using efficient bit sets. This representation is sometimes called a "balanced parenthesis tree."
Experiments suggest the inspector's traversals are about 2.5x faster than ast.Inspect, but it may take around 5 traversals for this benefit to amortize the inspector's construction cost. If efficiency is the primary concern, do not use Inspector for one-off traversals.
Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
Types ¶
type Inspector ¶
type Inspector struct {
// contains filtered or unexported fields
}
An Inspector provides methods for inspecting (traversing) the syntax trees of a package.
func (*Inspector) Nodes ¶
Nodes visits the nodes of the files supplied to New in depth-first order. It calls f(n, true) for each node n before it visits n's children. If f returns true, Nodes invokes f recursively for each of the non-nil children of the node, followed by a call of f(n, false).
The complete traversal sequence is determined by ast.Inspect. The types argument, if non-empty, enables type-based filtering of events. The function f if is called only for nodes whose type matches an element of the types slice.
func (*Inspector) Preorder ¶
Preorder visits all the nodes of the files supplied to New in depth-first order. It calls f(n) for each node n before it visits n's children.
The complete traversal sequence is determined by ast.Inspect. The types argument, if non-empty, enables type-based filtering of events. The function f is called only for nodes whose type matches an element of the types slice.
func (*Inspector) PreorderSeq ¶ added in v0.26.0
PreorderSeq returns an iterator that visits all the nodes of the files supplied to New in depth-first order. It visits each node n before n's children. The complete traversal sequence is determined by ast.Inspect.
The types argument, if non-empty, enables type-based filtering of events: only nodes whose type matches an element of the types slice are included in the sequence.
func (*Inspector) WithStack ¶
func (in *Inspector) WithStack(types []ast.Node, f func(n ast.Node, push bool, stack []ast.Node) (proceed bool))
WithStack visits nodes in a similar manner to Nodes, but it supplies each call to f an additional argument, the current traversal stack. The stack's first element is the outermost node, an *ast.File; its last is the innermost, n.
Source Files