[02/26] qapi: Clean up cgen() and mcgen()

Commit 05dfb26 added eatspace stripping to mcgen().  Move it to
cgen(), just in case somebody gets tempted to use cgen() directly
instead of via mcgen().

cgen() indents blank lines.  No such lines get generated right now,
but fix it anyway.

We use triple-quoted strings for program text, like this:

    '''
    Program text
    any number of lines
    '''

Keeps the program text relatively readable, but puts an extra newline
at either end.  mcgen() "fixes" that by dropping the first and last
line outright.  Drop only the newlines.

This unmasks a bug in qapi-commands.py: four quotes instead of three.
Fix it up.

Output doesn't change

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 scripts/qapi-commands.py |  2 +-
 scripts/qapi.py          | 19 ++++++++++++-------
 2 files changed, 13 insertions(+), 8 deletions(-)

Markus Armbruster <armbru@redhat.com> writes:

> Commit 05dfb26 added eatspace stripping to mcgen().  Move it to
> cgen(), just in case somebody gets tempted to use cgen() directly
> instead of via mcgen().
>
> cgen() indents blank lines.  No such lines get generated right now,
> but fix it anyway.
>
> We use triple-quoted strings for program text, like this:
>
>     '''
>     Program text
>     any number of lines
>     '''
>
> Keeps the program text relatively readable, but puts an extra newline
> at either end.  mcgen() "fixes" that by dropping the first and last
> line outright.  Drop only the newlines.
>
> This unmasks a bug in qapi-commands.py: four quotes instead of three.
> Fix it up.
>
> Output doesn't change
>
> Signed-off-by: Markus Armbruster <armbru@redhat.com>
> Reviewed-by: Eric Blake <eblake@redhat.com>
> ---
>  scripts/qapi-commands.py |  2 +-
>  scripts/qapi.py          | 19 ++++++++++++-------
>  2 files changed, 13 insertions(+), 8 deletions(-)
>
> diff --git a/scripts/qapi-commands.py b/scripts/qapi-commands.py
> index ca22acc..ce51408 100644
> --- a/scripts/qapi-commands.py
> +++ b/scripts/qapi-commands.py
> @@ -56,7 +56,7 @@ def gen_sync_call(name, args, ret_type, indent=0):
>                  name=c_name(name), args=arglist, retval=retval).rstrip()
>      if ret_type:
>          ret += "\n" + gen_err_check('local_err')
> -        ret += "\n" + mcgen(''''
> +        ret += "\n" + mcgen('''
>  %(marshal_output_call)s
>  ''',
>                              marshal_output_call=gen_marshal_output_call(name, ret_type)).rstrip()
> diff --git a/scripts/qapi.py b/scripts/qapi.py
> index 06d7fc2..20383ef 100644
> --- a/scripts/qapi.py
> +++ b/scripts/qapi.py
> @@ -943,16 +943,21 @@ def pop_indent(indent_amount=4):
>      global indent_level
>      indent_level -= indent_amount
>  
> +# Generate @code with @kwds interpolated.
> +# Obey indent_level, and strip eatspace.
>  def cgen(code, **kwds):
> -    indent = genindent(indent_level)
> -    lines = code.split('\n')
> -    lines = map(lambda x: indent + x, lines)
> -    return '\n'.join(lines) % kwds + '\n'
> -
> -def mcgen(code, **kwds):
> -    raw = cgen('\n'.join(code.split('\n')[1:-1]), **kwds)
> +    raw = code % kwds
> +    if indent_level:
> +        indent = genindent(indent_level)
> +        raw = re.subn("^.", indent + '\g<0>', raw, 0, re.MULTILINE)

pylint wants us to use r'\g<0>'.  If nothing else comes up, I'll fix
this up for my pull.

> +        raw = raw[0]
>      return re.sub(re.escape(eatspace) + ' *', '', raw)
>  
> +def mcgen(code, **kwds):
> +    if code[0] == '\n':
> +        code = code[1:]
> +    return cgen(code, **kwds)
> +
>  def basename(filename):
>      return filename.split("/")[-1]

On 08/04/2015 09:44 AM, Markus Armbruster wrote:
> Markus Armbruster <armbru@redhat.com> writes:
> 
>> Commit 05dfb26 added eatspace stripping to mcgen().  Move it to
>> cgen(), just in case somebody gets tempted to use cgen() directly
>> instead of via mcgen().
>>

>> Output doesn't change
>>
>> Signed-off-by: Markus Armbruster <armbru@redhat.com>
>> Reviewed-by: Eric Blake <eblake@redhat.com>
>> ---
>>  scripts/qapi-commands.py |  2 +-
>>  scripts/qapi.py          | 19 ++++++++++++-------
>>  2 files changed, 13 insertions(+), 8 deletions(-)

>> -def mcgen(code, **kwds):
>> -    raw = cgen('\n'.join(code.split('\n')[1:-1]), **kwds)
>> +    raw = code % kwds
>> +    if indent_level:
>> +        indent = genindent(indent_level)
>> +        raw = re.subn("^.", indent + '\g<0>', raw, 0, re.MULTILINE)
> 
> pylint wants us to use r'\g<0>'.  If nothing else comes up, I'll fix
> this up for my pull.
> 

Goes to show that I've never (yet) used pylint. I probably ought to :)

Fine by me to make that tweak and keep my R-b.