Re: Make several special characters with or without backslash "non-special" (issue 12432043)

[k-ohara5a5a]

Looks sensible.
The comments are confusing.
The commit message says almost the opposite of what you do.  Maybe
"Recognize )(][~| and \! etc. in the lexer.
Treat the ) in c4) like the \p command in c4\p but without the need for
an escape character, and similarly for '\)' ']' '\!' etc.  This requires
the lexer to recognize these characters and their escaped versions, but
simplifies the parser, and allows ")" to be (re-)defined in LilyPond
code.
Two characters, '~' and '|', had a second meaning in some contexts,
formerly distinguished in the parser, so we change \tempo 20~30 to
\tempo 20-30 and the staccatissimo indication to -! "

Changing staccatissimo to -! should get a short1 entry in 'changes.tely'


https://codereview.appspot.com/12432043/diff/6001/input/regression/articulation-syntax-change.ly
File input/regression/articulation-syntax-change.ly (right):

https://codereview.appspot.com/12432043/diff/6001/input/regression/articulation-syntax-change.ly#newcode3
input/regression/articulation-syntax-change.ly:3: texidoc = "The
syntactic class of articulations can be changed within
It is confusing to put it this way.

We could always redefine post events to create an empty chord
trill = <>\trill
Now we can redefine ) as well

It is not clear what functionality you are protecting from regression.
Probably this added regression test is not needed, because the usual
definition and use of ")" tests the new code.

https://codereview.appspot.com/12432043/diff/6001/lily/lexer.ll
File lily/lexer.ll (right):

https://codereview.appspot.com/12432043/diff/6001/lily/lexer.ll#newcode153
lily/lexer.ll:153: SPECIAL              \\.|[][|()~]
'special' is vague. Maybe POST_EVENT_CHAR

I wonder why you didn't make an explicit list of the escaped
single-characters,
POST_EVENT_CHAR    [][|)(~]
POST_EVENT_COMMAND \\[][)(><~!\\]
so you catch errors like \= as an unexpected '=' rather than undefined
command "=".

https://codereview.appspot.com/12432043/diff/6001/python/convertrules.py
File python/convertrules.py (right):

https://codereview.appspot.com/12432043/diff/6001/python/convertrules.py#newcode3614
python/convertrules.py:3614: str = re.sub (r"([-^_])\||" + matchstring +
r"|[-^_][-^_]", subnonstring, str)
convert-ly rules are unlikely to be maintained, but this one is so
non-obvious that you might still want a comment:
# Match strings, and articulations that end in -^_
# So that we avoid leave alone -| in quoted strings and c4--|

https://codereview.appspot.com/12432043/