astquery
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astquery select a node set from AST by XPath
astquery ![PkgGoDev](https://pkg.go.dev/badge/github.com/gostaticanalysis/astquery)
astquery
selects a node set from AST by XPath.
astquery
uses antchfx/xpath.
You can see a document of xpath expressions at antchfx/xpath's repository.
You can also use field of a node as an attributes such as @Name
for *ast.Ident
.
In addtion you can use the follows as an attribute:
-
@type
: type of a node -
@pos
:token.Position
of a node in string value -
@src
: source code representation of a node with"go/format".Node
CLI Tool
Install
$ go get -u github.com/gostaticanalysis/astquery/cmd/astquery
How to use
Select a node set
$ astquery '//*[@type="CallExpr"]/Fun[@type="Ident" and @Name="panic"]' fmt
Select attributes
# Find calling panic in fmt package
$ astquery '//*[@type="CallExpr"]/Fun[@type="Ident" and @Name="panic"]/@pos' fmt
/usr/local/go/src/fmt/format.go:266:3
/usr/local/go/src/fmt/print.go:553:4
/usr/local/go/src/fmt/scan.go:240:2
/usr/local/go/src/fmt/scan.go:244:2
/usr/local/go/src/fmt/scan.go:253:5
/usr/local/go/src/fmt/scan.go:508:3
/usr/local/go/src/fmt/scan.go:1064:4
# Find with src code snipet
$ astquery '//*[starts-with(@src, "panic") and @type="CallExpr"]/@src' fmt
panic("fmt: unknown base; can't happen")
panic(err)
panic(scanError{err})
panic(scanError{errors.New(err)})
panic(e)
panic(io.EOF)
panic(e)
Analyzer
see: examples of analysis.Analyzer
func run(pass *analysis.Pass) (interface{}, error) {
e := pass.ResultOf[astquery.Analyzer].(*astquery.Evaluator)
ns, err := e.Select("//*[@type='CallExpr']/Fun[@type='Ident' and @Name='panic']")
if err != nil {
return nil, err
}
for _, n := range ns {
pass.Reportf(n.Pos(), "don't panic")
}
return nil, nil
}