marcandre.lureau@redhat.com writes:

> From: Marc-André Lureau <marcandre.lureau@redhat.com>
>
> Replace the simple list sugar form with a recursive structure that will
> accept other operators in the following commits (all, any or not).
>
> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> ---
>  scripts/qapi/common.py                        | 23 +++++--
>  scripts/qapi/expr.py                          | 52 ++++++++++------
>  scripts/qapi/schema.py                        |  2 +-
>  tests/qapi-schema/bad-if-empty-list.json      |  2 +-
>  tests/qapi-schema/bad-if-list.json            |  2 +-
>  tests/qapi-schema/bad-if.err                  |  3 +-
>  tests/qapi-schema/doc-good.json               |  3 +-
>  tests/qapi-schema/doc-good.out                | 13 ++--
>  tests/qapi-schema/doc-good.txt                |  6 ++
>  tests/qapi-schema/enum-if-invalid.err         |  3 +-
>  tests/qapi-schema/features-if-invalid.err     |  2 +-
>  tests/qapi-schema/qapi-schema-test.json       | 25 ++++----
>  tests/qapi-schema/qapi-schema-test.out        | 62 +++++++++----------
>  .../qapi-schema/struct-member-if-invalid.err  |  2 +-
>  .../qapi-schema/union-branch-if-invalid.json  |  2 +-
>  15 files changed, 119 insertions(+), 83 deletions(-)
>
> diff --git a/scripts/qapi/common.py b/scripts/qapi/common.py
> index 5181a0f167..51463510c9 100644
> --- a/scripts/qapi/common.py
> +++ b/scripts/qapi/common.py
> @@ -13,7 +13,8 @@
> 
>  import re
>  from typing import (
> -    List,
> +    Any,
> +    Dict,
>      Match,
>      Optional,
>      Union,
> @@ -199,16 +200,28 @@ def guardend(name: str) -> str:
>                   name=c_fname(name).upper())
> 
> 
> -def cgen_ifcond(ifcond: Union[str, List[str]]) -> str:
> +def docgen_ifcond(ifcond: Union[str, Dict[str, Any]]) -> str:

Uh, why do you swap cgen_ifcond() and docgen_ifcond()?  Accident?

>      if not ifcond:
>          return ''
> -    return '(' + ') && ('.join(ifcond) + ')'
> +    if isinstance(ifcond, str):
> +        return ifcond
> 
> +    oper, operands = next(iter(ifcond.items()))
> +    oper = {'all': ' and '}[oper]
> +    operands = [docgen_ifcond(o) for o in operands]
> +    return '(' + oper.join(operands) + ')'

What a nice review speedbump you buried here...

The whole block boils down to the much less exciting

       operands = [docgen_ifcond(o) for o in ifcond['all']]
       return '(' + ' and '.join(operands) + ')'

Peeking ahead, I understand that you did it this way here so you can
extend it trivially there.  Matter of taste; what counts is the final
result and minimizing reviewer WTFs/minute along the way.

Since the WTFs/minute is a done deed now, what remains is the final
result, which I expect to review shortly.  But please try a bit harder
to be boring next time ;)

> 
> -def docgen_ifcond(ifcond: Union[str, List[str]]) -> str:
> +
> +def cgen_ifcond(ifcond: Union[str, Dict[str, Any]]) -> str:
>      if not ifcond:
>          return ''
> -    return ' and '.join(ifcond)
> +    if isinstance(ifcond, str):
> +        return ifcond

This is what gets rid of the redundant parenthesises in the common case
"single condition string".

> +
> +    oper, operands = next(iter(ifcond.items()))
> +    oper = {'all': '&&'}[oper]
> +    operands = [cgen_ifcond(o) for o in operands]
> +    return '(' + (') ' + oper + ' (').join(operands) + ')'

This line is hard to read.  Easier, I think:

       oper = {'all': ' && '}[oper]
       operands = ['(' + cgen_ifcond(o) + ')' for o in operands]
       return oper.join(operands)

Neither your version nor mine gets rid of the redundant parenthesises in
the (uncommon) case "complex condition expression".
tests/test-qapi-introspect.c still has

    #if (defined(TEST_IF_COND_1)) && (defined(TEST_IF_COND_2))
                QLIT_QSTR("feature1"),
    #endif /* (defined(TEST_IF_COND_1)) && (defined(TEST_IF_COND_2)) */

Mildly annoying.  I'm willing to leave this for later.

Code smell: cgen_ifcond() and docgen_ifcond() are almost identical.  Can
also be left for later.

> 
> 
>  def gen_if(cond: str) -> str:
> diff --git a/scripts/qapi/expr.py b/scripts/qapi/expr.py
> index 496f7e0333..3ee66c5f62 100644
> --- a/scripts/qapi/expr.py
> +++ b/scripts/qapi/expr.py
> @@ -259,14 +259,12 @@ def check_flags(expr: _JSONObject, info: QAPISourceInfo) -> None:
> 
>  def check_if(expr: _JSONObject, info: QAPISourceInfo, source: str) -> None:
>      """
> -    Normalize and validate the ``if`` member of an object.
> +    Validate the ``if`` member of an object.
> 
> -    The ``if`` member may be either a ``str`` or a ``List[str]``.
> -    A ``str`` value will be normalized to ``List[str]``.
> +    The ``if`` member may be either a ``str`` or a dict.
> 
>      :forms:
> -      :sugared: ``Union[str, List[str]]``
> -      :canonical: ``List[str]``
> +      :canonical: ``Union[str, dict]``

Does this :forms: thing make sense without any :sugared:?  John, you
added (invented?) it in commit a48653638fa, but no explanation made it
into the tree.