有没有办法在 Ocamllex 规范中使用区分大小写的 token ?
我已经尝试以这种方式制作不区分大小写的 token :
let token = parser
...
| ['C''c']['A''a']['S''s']['E''e'] { CASE }
...
但我正在寻找其他东西,如果存在的话。
最佳答案
使用接受小写和大写的普通标记词法分析器,并在表中查找关键字,忽略大小写:
{
type token = Case | Test | Ident of string
let keyword_tbl = Hashtbl.create 64
let _ = List.iter (fun (name, keyword) ->
Hashtbl.add keyword_tbl name keyword) [
"case", Case;
"test", Test;
]
}
let ident_char = ['a'-'z' 'A'-'Z' '_']
rule next_token = parse
| ident_char+ as s {
let canon = String.lowercase s in
try Hashtbl.find keyword_tbl canon
with Not_found ->
(* `Ident canon` if you want case-insensitive vars as well
* as keywords *)
Ident s
}
关于OCamlLex 不区分大小写,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/35068495/