Old implementation uses involved Flex input management technique that
requires usage of obsolete YY_INPUT macro. This causes a lot of useless
allocations and byte-by-byte scanning. New implementation avoids those
hacks, it uses yy_scan_string() API to setup Flex input. Also it fixes
reporting of syntax error position and corresponding tests.
clang scan-build warns about YY_CURRENT_BUFFER_LVALUE being zero-
allocated, but the whole point of the macro is to know that it's
not zero. Wrap the entire file in an "#ifndef __clang_analyzer__"
block in order to suppress the warning.
flex 2.6.3 introduces symbol remapping through macro definitions. hence the
change appears bigger than one would expect from a minor version upgrade.
In addition some manual cleanup that had to be done previously is now
obsolete. namely:
- the size_t cast of _yybytes_len in yy_scan_bytes
(i is now also defined int and not size_t anymore)
- the redefinition of yyl within yy_find_action
(yyl is now already defined as int)
Line number preprocessor directives (#line) were previously generated into
the c source file. This actually breaks debugging as debuggers have a hard
time finding the original cmCommandArgumentLexer.in.l and mapping the current
instruction to a meaningful location within that file.
The prefix "cmCommandArgument_yy" can already be set as %option directly.
For convenience also provide a sed command for all the manual steps that
need to be done after generating.
Signed-off-by: Matthias Maennich <matthias@maennich.net>
