> As far as I know the most likely next evolutionary step in this area will be to replace the Node tree with the cmd/compile/internal/syntax tree. hello All, I have a question. As far as I know, the AST transformation phase has been in existence for several years now. So I want to know the reason why the AST transformation phase has not been eliminated now?
Thanks in advance. 在2019年9月3日星期二 UTC+8 下午11:37:58<Vincent Blanchon> 写道： > Hello Ian, > > Thank you for your answer. > > Why do you ask? > > > Just out of curiosity, I was working with the SSA package for a tool, and > since the compiler uses this package as well I wanted to go a bit deeper on > that and write a small article on it. That's quite an interesting part but > the usage of two different syntax tree was a bit confusing. > > Hope this helps > > > Yes, a lot. Thanks again! > > Le mardi 3 septembre 2019 17:54:38 UTC+4, Ian Lance Taylor a écrit : >> >> On Tue, Sep 3, 2019 at 6:23 AM Vincent Blanchon >> <blancho...@gmail.com> wrote: >> > >> > The compiler documentation mentions a syntax tree in the parsing phase >> when the AST transformation phase mentions a conversion from the syntax >> tree to the compiler's AST representation. >> > If I do not misunderstand, the command "go tool compile -W" will >> display the AST. >> > >> > I was wondering how far is different the syntax tree from the AST? >> Where could I get documentation or an example of this syntax tree? >> >> Note that AST just means Abstract Syntax Tree, so it's a little >> confusing to talk converting a syntax tree to an AST. What we really >> have is two different ASTs. >> >> Unfortunately none of this stuff is well documented. The parser >> generates a syntax tree as defined in cmd/compile/internal/syntax. >> That is then converted to the Node tree defined in >> cmd/compile/internal/gc/syntax.go. The -W option dumps the latter. I >> don't know of a way to dump the former, but perhaps there is one. >> >> > Also, is this syntax tree mandatory? Is it not possible to build the >> AST directly from the lexer+parser? >> >> The use of two different syntax trees is entirely historical due to >> the evolution of the compiler. The original code base was a C >> compiler written in C which became a Go compiler written in C which >> was machine translated from C to Go. There has been a lot of cleanup >> but there is still a lot of historical cruft. As far as I know the >> most likely next evolutionary step in this area will be to replace the >> Node tree with the cmd/compile/internal/syntax tree. >> >> Hope this helps, and I hope someone will correct me if I made a mistake. >> >> Why do you ask? >> >> Ian >> > -- 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/c765be68-1745-4d98-84b3-7762745cea6en%40googlegroups.com.
