[Libguestfs] [PATCH] python: Add type hints

[Richard W.M. Jones]

On Mon, Jul 06, 2020 at 07:50:19PM +0300, Sam Eiderman wrote:
> Since support for python2 is dropped we can use the new python3 syntax
> for type hints.

Interesting - didn't know about this.

I have pushed this, and another patch to update the published minimum
version of Python to 3.6.  I don't test anything earlier, although in
theory it could work for 3.5 still.

Rich.

> Signed-off-by: Sam Eiderman <sameid at google.com>
> ---
>  generator/python.ml | 39 +++++++++++++++++++++++++++++++++++----
>  1 file changed, 35 insertions(+), 4 deletions(-)
> 
> diff --git a/generator/python.ml b/generator/python.ml
> index f0d6b5d96..3640ee39a 100644
> --- a/generator/python.ml
> +++ b/generator/python.ml
> @@ -685,6 +685,7 @@ logvols = g.lvs()
>  import os
>  import sys
>  import libguestfsmod
> +from typing import Union, List, Tuple, Optional
>  
>  ";
>  
> @@ -802,14 +803,44 @@ class GuestFS(object):
>      fun f ->
>        let ret, args, optargs = f.style in
>        let len_name = String.length f.name in
> +      let ret_type_hint =
> +        match ret with
> +        | RErr -> "None"
> +        | RInt _ | RInt64 _ -> "int"
> +        | RBool _ -> "bool"
> +        | RConstOptString _ -> "Optional[str]"
> +        | RConstString _ | RString _ -> "str"
> +        | RBufferOut _ -> "bytes"
> +        | RStringList _ -> "List[str]"
> +        | RStruct _ -> "dict"
> +        | RStructList _ -> "List[dict]"
> +        | RHashtable _ -> "Union[List[Tuple[str, str]], dict]" in
> +      let type_hint_of_argt arg =
> +        match arg with
> +        | String _ -> ": str"
> +        | OptString _ -> ": Optional[str]"
> +        | Bool _ -> ": bool"
> +        | Int _ | Int64 _ -> ": int"
> +        | BufferIn _ -> ": bytes"
> +        | StringList _ -> ": List[str]"
> +        | Pointer _ -> ""
> +      in
> +      let type_hint_of_optargt optarg =
> +        match optarg with
> +        | OBool _ -> "bool"
> +        | OInt _ | OInt64 _ -> "int"
> +        | OString _ -> "str"
> +        | OStringList _ -> "List[str]"
> +      in
>        let decl_string =
>          "self" ^
> -        map_join (fun arg ->sprintf ", %s" (name_of_argt arg))
> +        map_join (fun arg ->sprintf ", %s%s" (name_of_argt arg) (type_hint_of_argt arg))
>            args ^
> -        map_join (fun optarg -> sprintf ", %s=None" (name_of_optargt optarg))
> -          optargs in
> +        map_join (fun optarg -> sprintf ", %s: Optional[%s] = None" (name_of_optargt optarg) (type_hint_of_optargt optarg))
> +          optargs ^
> +        ") -> " ^ ret_type_hint ^ ":" in
>        pr "\n";
> -      pr "    def %s(%s):\n"
> +      pr "    def %s(%s\n"
>          f.name (indent_python decl_string (9 + len_name) 78);
>  
>        if is_documented f then (
> -- 
> 2.27.0.212.ge8ba1cc988-goog
> 
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-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
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