Hi Max, Great answer, thank you! Exactly what I was looking for in terms of a fluid api, no need for parsing the selectors.
The API is not quite suitable for public consumption. I feel this could be a great success if extracted into its own module. Could you kindly clarify what the meaning of the int parameters is, i.e. is there a general rule or does it depend on the function? I‘ll play a bit with it and will comment on GH if ok. Much appreciated, Andi On Wednesday, October 14, 2020 at 6:09:08 PM UTC+2 Max wrote: > I can only agree, traversing or navigating Go AST is cumbersome for at > least two reasons: > 1. each type has its own fields - no uniform API is available > 2. you often need type assertions on fields because they have interface > type instead of concrete type > > I developed a wrapper around them to mitigate these problems for my Go > interpreter https://github.com/cosmos72/gomacro > If you are interested, it is the package > https://github.com/cosmos72/gomacro/tree/master/ast2 > > You may find it helps by providing an uniform API and removing the need > for type assertions, but it still requires compile-time code, > not CSS-style strings that can be created at runtime. > > A quick example: this uses plain go/ast > ``` > package main > import ( > "fmt" > "go/ast" > "go/parser" > ) > func main() { > x, _ := parser.ParseExpr("foo[1 + 2 * 3]") > // we want to extract the "3" > var three string = > x.(*ast.IndexExpr).Index.(*ast.BinaryExpr).Y.(*ast.BinaryExpr).Y.(*ast.BasicLit).Value > fmt.Printf("%s\n", three) // prints 3 > } > ``` > while this is the equivalent using github.com/cosmos72/gomacro/ast2 > ``` > package main > import ( > "fmt" > "go/ast" > "go/parser" > "github.com/cosmos72/gomacro/ast2" > ) > func main() { > x, _ := parser.ParseExpr("foo[1 + 2 * 3]") > y := ast2.AnyToAst(x, nil) // wrap the existing AST. does not allocate > memory. > > ythree := y.Get(1).Get(1).Get(1) // extract the "3" as ast2.Node > > // now unwrap it, getting the *ast.BasicLit and the Value inside it > var three string = ast2.ToBasicLit(ythree).Value > fmt.Printf("%s\n", three) // prints 3 > } > ``` > > On Tuesday, October 13, 2020 at 9:37:21 AM UTC+2 cpu...@gmail.com wrote: > >> Good morning. >> >> I've recently found myself writing a code generator for dynamic interface >> composition at runtime. It became ugly and I had to pass in quite a number >> of parameters that should have been available from reading the source code. >> >> In a second attempt I've reimplemented the generator using stringer-like >> AST handling. It worked well but was cumbersome to code. >> >> Now an idea surfaced: wouldn't it make sense to implement a selector >> interface on top of the golang AST, something like CSS or JQ selectors but >> targeted at the go language constructs? I've stumbled across Guru but it >> does seem to target a slightly different use case. >> >> Is anybody aware of such a selector lib/module or does the idea even >> sound interesting? >> >> Cheers, >> Andi >> > -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/golang-nuts/d7eca821-f060-49de-b9cd-67d1b95d2b70n%40googlegroups.com.
