Re: [PATCH 16/16] qapi/expr.py: Use an expression checker dispatch table

[John Snow]

On 9/26/20 7:31 AM, Helio Loureiro wrote:



On Fri, Sep 25, 2020, 16:16 John Snow > wrote:


On 9/25/20 2:03 AM, Helio Loureiro wrote:
 > Hi,
 >
 > I would replace the word variable "kind" by "category".
 >

Hi, welcome to the list!


Tkz!


For patch reviews, we try to reply in-line, below the original post.


I realized that later.  It has been more than 20 years I don't use this 
formating.  But if I intend to join the pack, I need to follow the pack.




(For more information on the QAPI Schema Language that we are parsing
and validating here, see docs/devel/qapi-code-gen.txt if you are
curious. Ultimately it is a JSON-like format that permits multiple
objects per document and allows comments. We use these structures to
generate types and command interfaces for our API protocol, QMP.)


Based on that I would suggest 'type_ref' instead to match the 
definitions over there and since word 'type' itself is reserved.




One of the unsolvable problems in computer science is naming things: 
"TYPE-REF" also has a specific meaning in QAPI, as it is the name of one 
of the BNF grammar tokens we use.


So I might suggest (if "kind" is too ambiguous), that I might use 
"statement_type" or "expression_type" if that helps clarify things.


--js

Re: [PATCH 16/16] qapi/expr.py: Use an expression checker dispatch table

[Helio Loureiro]

On Fri, Sep 25, 2020, 16:16 John Snow  wrote:

> On 9/25/20 2:03 AM, Helio Loureiro wrote:
> > Hi,
> >
> > I would replace the word variable "kind" by "category".
> >
>
> Hi, welcome to the list!
>

Tkz!


> For patch reviews, we try to reply in-line, below the original post.
>

I realized that later.  It has been more than 20 years I don't use this
formating.  But if I intend to join the pack, I need to follow the pack.

>
>
(For more information on the QAPI Schema Language that we are parsing
> and validating here, see docs/devel/qapi-code-gen.txt if you are
> curious. Ultimately it is a JSON-like format that permits multiple
> objects per document and allows comments. We use these structures to
> generate types and command interfaces for our API protocol, QMP.)
>

Based on that I would suggest 'type_ref' instead to match the definitions
over there and since word 'type' itself is reserved.


>
>
./helio

>

Re: [PATCH 16/16] qapi/expr.py: Use an expression checker dispatch table

[John Snow]

On 9/25/20 12:38 PM, Cleber Rosa wrote:

On Thu, Sep 24, 2020 at 09:32:05PM -0400, John Snow wrote:

On 9/24/20 9:18 PM, Cleber Rosa wrote:

I have to say the style of this line bothers me, but it's just that,
style. So,


What don't you like?


It's the sum of the "private" + "global dictionary" + "its item being
called directly".

But don't bother, this is probably the kind of comment that I should
omit, as I don't want you to, say, create a wrapper function around
the dict, partially defeating the purpose of this patch.



ACK, just wanted to know what the style nit was. Thanks :)

--js

Re: [PATCH 16/16] qapi/expr.py: Use an expression checker dispatch table

[Cleber Rosa]

On Thu, Sep 24, 2020 at 09:32:05PM -0400, John Snow wrote:
> On 9/24/20 9:18 PM, Cleber Rosa wrote:
> > I have to say the style of this line bothers me, but it's just that,
> > style. So,
> 
> What don't you like?

It's the sum of the "private" + "global dictionary" + "its item being
called directly".

But don't bother, this is probably the kind of comment that I should
omit, as I don't want you to, say, create a wrapper function around
the dict, partially defeating the purpose of this patch.

- Cleber.


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Re: [PATCH 16/16] qapi/expr.py: Use an expression checker dispatch table

[John Snow]

On 9/25/20 2:03 AM, Helio Loureiro wrote:

Hi,

I would replace the word variable "kind" by "category".



Hi, welcome to the list!

For patch reviews, we try to reply in-line, below the original post.

I'm not attached to 'kind', but 'category' is perhaps too broad. 
Category in this particular domain might refer to the difference between 
a "Directive" (include, pragma) and a Definition (enum, struct, union, 
alternate, command, event)


(For more information on the QAPI Schema Language that we are parsing 
and validating here, see docs/devel/qapi-code-gen.txt if you are 
curious. Ultimately it is a JSON-like format that permits multiple 
objects per document and allows comments. We use these structures to 
generate types and command interfaces for our API protocol, QMP.)


Ultimately I am using 'kind' for the 'type of expression', but type is 
an extremely overloaded word when parsing a language in another language!


We also use 'meta' nearby for semantically the same thing, but with 
different typing.


Thanks for looking!
--js


./helio

On Fri, Sep 25, 2020, 03:32 John Snow > wrote:


On 9/24/20 9:18 PM, Cleber Rosa wrote:
 > I have to say the style of this line bothers me, but it's just that,
 > style. So,

What don't you like?

Re: [PATCH 16/16] qapi/expr.py: Use an expression checker dispatch table

[Helio Loureiro]

Hi,

I would replace the word variable "kind" by "category".

./helio

On Fri, Sep 25, 2020, 03:32 John Snow  wrote:

> On 9/24/20 9:18 PM, Cleber Rosa wrote:
> > I have to say the style of this line bothers me, but it's just that,
> > style. So,
>
> What don't you like?
>
>
>

Re: [PATCH 16/16] qapi/expr.py: Use an expression checker dispatch table

[John Snow]

On 9/24/20 9:18 PM, Cleber Rosa wrote:

I have to say the style of this line bothers me, but it's just that,
style. So,


What don't you like?

Re: [PATCH 16/16] qapi/expr.py: Use an expression checker dispatch table

[Cleber Rosa]

On Tue, Sep 22, 2020 at 05:13:13PM -0400, John Snow wrote:
> This enforces a type signature against all of the top-level expression
> check routines without necessarily needing to create some
> overcomplicated class hierarchy for them.
> 
> Signed-off-by: John Snow 
> ---
>  scripts/qapi/expr.py | 69 ++--
>  1 file changed, 35 insertions(+), 34 deletions(-)
> 
> diff --git a/scripts/qapi/expr.py b/scripts/qapi/expr.py
> index 74b2681ef8..cfd342aa04 100644
> --- a/scripts/qapi/expr.py
> +++ b/scripts/qapi/expr.py
> @@ -31,8 +31,11 @@
>  structures and contextual semantic validation.
>  """
>  
> +from enum import Enum
>  import re
>  from typing import (
> +Callable,
> +Dict,
>  Iterable,
>  List,
>  MutableMapping,
> @@ -494,6 +497,26 @@ def check_event(expr: Expression, info: QAPISourceInfo) 
> -> None:
>  check_type(args, info, "'data'", allow_dict=not boxed)
>  
>  
> +class ExpressionType(str, Enum):
> +INCLUDE = 'include'
> +ENUM = 'enum'
> +UNION = 'union'
> +ALTERNATE = 'alternate'
> +STRUCT = 'struct'
> +COMMAND = 'command'
> +EVENT = 'event'
> +
> +
> +_CHECK_FN: Dict[str, Callable[[Expression, QAPISourceInfo], None]] = {
> +'enum': check_enum,
> +'union': check_union,
> +'alternate': check_alternate,
> +'struct': check_struct,
> +'command': check_command,
> +'event': check_event,
> +}
> +
> +
>  def check_exprs(exprs: List[_JSObject]) -> List[_JSObject]:
>  """
>  Validate and normalize a list of parsed QAPI schema expressions. [RW]
> @@ -519,28 +542,20 @@ def check_exprs(exprs: List[_JSObject]) -> 
> List[_JSObject]:
>  assert tmp is None or isinstance(tmp, QAPIDoc)
>  doc: Optional[QAPIDoc] = tmp
>  
> -if 'include' in expr:
> -continue
> -
> -if 'enum' in expr:
> -meta = 'enum'
> -elif 'union' in expr:
> -meta = 'union'
> -elif 'alternate' in expr:
> -meta = 'alternate'
> -elif 'struct' in expr:
> -meta = 'struct'
> -elif 'command' in expr:
> -meta = 'command'
> -elif 'event' in expr:
> -meta = 'event'
> +for kind in ExpressionType:
> +if kind in expr:
> +meta = kind
> +break
>  else:
>  raise QAPISemError(info, "expression is missing metatype")
>  
> +if meta == ExpressionType.INCLUDE:
> +continue
> +
>  name = cast(str, expr[meta])  # asserted right below:
> -check_name_is_str(name, info, "'%s'" % meta)
> -info.set_defn(meta, name)
> -check_defn_name_str(name, info, meta)
> +check_name_is_str(name, info, "'%s'" % meta.value)
> +info.set_defn(meta.value, name)
> +check_defn_name_str(name, info, meta.value)
>  
>  if doc:
>  if doc.symbol != name:
> @@ -551,22 +566,8 @@ def check_exprs(exprs: List[_JSObject]) -> 
> List[_JSObject]:
>  raise QAPISemError(info,
> "documentation comment required")
>  
> -if meta == 'enum':
> -check_enum(expr, info)
> -elif meta == 'union':
> -check_union(expr, info)
> -elif meta == 'alternate':
> -check_alternate(expr, info)
> -elif meta == 'struct':
> -check_struct(expr, info)
> -elif meta == 'command':
> -check_command(expr, info)
> -elif meta == 'event':
> -check_event(expr, info)
> -else:
> -assert False, 'unexpected meta type'
> -
> -check_if(expr, info, meta)
> +_CHECK_FN[meta](expr, info)

I have to say the style of this line bothers me, but it's just that,
style. So,

Reviewed-by: Cleber Rosa 


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Re: [PATCH 16/16] qapi/expr.py: Use an expression checker dispatch table

[John Snow]

On 9/23/20 4:36 PM, Eduardo Habkost wrote:

I see lots of meta.value expressions below.  Maybe setting
   meta = kind.value
will make the code more readable?



I can do that.


I don't think this should block an obvious improvement to the
code, so:

Reviewed-by: Eduardo Habkost


Thanks!

--js

Re: [PATCH 16/16] qapi/expr.py: Use an expression checker dispatch table

[Eduardo Habkost]

On Tue, Sep 22, 2020 at 05:13:13PM -0400, John Snow wrote:
> This enforces a type signature against all of the top-level expression
> check routines without necessarily needing to create some
> overcomplicated class hierarchy for them.
> 
> Signed-off-by: John Snow 
> ---
>  scripts/qapi/expr.py | 69 ++--
>  1 file changed, 35 insertions(+), 34 deletions(-)
> 
> diff --git a/scripts/qapi/expr.py b/scripts/qapi/expr.py
> index 74b2681ef8..cfd342aa04 100644
> --- a/scripts/qapi/expr.py
> +++ b/scripts/qapi/expr.py
> @@ -31,8 +31,11 @@
>  structures and contextual semantic validation.
>  """
>  
> +from enum import Enum
>  import re
>  from typing import (
> +Callable,
> +Dict,
>  Iterable,
>  List,
>  MutableMapping,
> @@ -494,6 +497,26 @@ def check_event(expr: Expression, info: QAPISourceInfo) 
> -> None:
>  check_type(args, info, "'data'", allow_dict=not boxed)
>  
>  
> +class ExpressionType(str, Enum):
> +INCLUDE = 'include'
> +ENUM = 'enum'
> +UNION = 'union'
> +ALTERNATE = 'alternate'
> +STRUCT = 'struct'
> +COMMAND = 'command'
> +EVENT = 'event'
> +
> +
> +_CHECK_FN: Dict[str, Callable[[Expression, QAPISourceInfo], None]] = {
> +'enum': check_enum,
> +'union': check_union,
> +'alternate': check_alternate,
> +'struct': check_struct,
> +'command': check_command,
> +'event': check_event,
> +}
> +
> +
>  def check_exprs(exprs: List[_JSObject]) -> List[_JSObject]:
>  """
>  Validate and normalize a list of parsed QAPI schema expressions. [RW]
> @@ -519,28 +542,20 @@ def check_exprs(exprs: List[_JSObject]) -> 
> List[_JSObject]:
>  assert tmp is None or isinstance(tmp, QAPIDoc)
>  doc: Optional[QAPIDoc] = tmp
>  
> -if 'include' in expr:
> -continue
> -
> -if 'enum' in expr:
> -meta = 'enum'
> -elif 'union' in expr:
> -meta = 'union'
> -elif 'alternate' in expr:
> -meta = 'alternate'
> -elif 'struct' in expr:
> -meta = 'struct'
> -elif 'command' in expr:
> -meta = 'command'
> -elif 'event' in expr:
> -meta = 'event'
> +for kind in ExpressionType:
> +if kind in expr:
> +meta = kind

I see lots of meta.value expressions below.  Maybe setting
  meta = kind.value
will make the code more readable?

I don't think this should block an obvious improvement to the
code, so:

Reviewed-by: Eduardo Habkost 

> +break
>  else:
>  raise QAPISemError(info, "expression is missing metatype")
>  
> +if meta == ExpressionType.INCLUDE:
> +continue
> +
>  name = cast(str, expr[meta])  # asserted right below:
> -check_name_is_str(name, info, "'%s'" % meta)
> -info.set_defn(meta, name)
> -check_defn_name_str(name, info, meta)
> +check_name_is_str(name, info, "'%s'" % meta.value)
> +info.set_defn(meta.value, name)
> +check_defn_name_str(name, info, meta.value)
>  
>  if doc:
>  if doc.symbol != name:
> @@ -551,22 +566,8 @@ def check_exprs(exprs: List[_JSObject]) -> 
> List[_JSObject]:
>  raise QAPISemError(info,
> "documentation comment required")
>  
> -if meta == 'enum':
> -check_enum(expr, info)
> -elif meta == 'union':
> -check_union(expr, info)
> -elif meta == 'alternate':
> -check_alternate(expr, info)
> -elif meta == 'struct':
> -check_struct(expr, info)
> -elif meta == 'command':
> -check_command(expr, info)
> -elif meta == 'event':
> -check_event(expr, info)
> -else:
> -assert False, 'unexpected meta type'
> -
> -check_if(expr, info, meta)
> +_CHECK_FN[meta](expr, info)
> +check_if(expr, info, meta.value)
>  check_features(expr.get('features'), info)
>  check_flags(expr, info)
>  
> -- 
> 2.26.2
> 

-- 
Eduardo