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callbacks, but tries to use static assertions
* Requiring state callbacks by generating their names (e.g. NAME##_input) has several disadvantages:
* The callback is not explicitly referenced when the state is defined.
So an unintroduced reader will see some static function, which is nowhere referenced and still
doesn't cause "unused" warnings.
* You cannot choose the name of function that implements the callback freely.
* In "substates" you need to generate a callback function if you want to provide a default.
You also need to provide dummy wrapper functions whenever you want to reuse some existing
function as the implementation.
* Instead, we are now using static assertions to check whether certain callbacks have been
implemented.
Unfortunately, this does not work on all compilers. In particular GCC won't consider
references to state objects fully constant (even though they are) and does not allow
them in _Static_assert (G_STATIC_ASSERT). This could only be made to work in newer GCC
with -std=c2x or -std=gnu23 in combination with constexpr.
It does work on Clang, though.
So I introduced TECO_ASSERT_SAFE() which also passes if the expression is *not* constant.
These static assertions are not crucial - they do not check anything that can differ between
systems. So we can always rely on the checks performed by FreeBSD CI for instance.
Also, you will of course quickly notice missing callbacks at runtime - with and without
additional runtime assertions.
* All mandatory callbacks must still be explicitly initialized in the TECO_DEFINE_STATE calls.
* After getting rid of generated callback implementations, the TECO_DEFINE_STATE macros
can finally be qualified with `static`.
* The TECO_DECLARE_STATE() macro has been removed. It no longer abstracts anything
and cannot be used to declare static teco_state_t anyway.
Also TECO_DEFINE_UNDO_CALL() also doesn't have a DECLARE counterpart.
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statement
* this is a SciTECO extension - it's not in TECO-11
* Allows for select-case-like constructs with default-clauses as in
:Os.^EQa$
!* default *!
!s.foo!
!* ... *!
!s.bar!
!* ... *!
* Consistent with nOlabel0,label1,...$ if <n> is out of range.
Unfortunately this form of computed goto is not applicable when
"selecting" by strings or non-consecutive integers.
* In order to continue after the <:O> statement, we must keep the
program counter along with the label we were looking for.
At the end of the macro, the PC is restored instead of throwing
an error.
* Since that would be very inefficient in loops - where potentially
all iterations would result in rescanning till the end of the
macro - we now store a completed-flag in the goto table.
If it is set while trying to :O to an unknown label, we can
just continue execution.
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This is a total conversion of SciTECO to plain C (GNU C11).
The chance was taken to improve a lot of internal datastructures,
fix fundamental bugs and lay the foundations of future features.
The GTK user interface is now in an useable state!
All changes have been squashed together.
The language itself has almost not changed at all, except for:
* Detection of string terminators (usually Escape) now takes
the string building characters into account.
A string is only terminated outside of string building characters.
In other words, you can now for instance write
I^EQ[Hello$world]$
This removes one of the last bits of shellisms which is out of
place in SciTECO where no tokenization/lexing is performed.
Consequently, the current termination character can also be
escaped using ^Q/^R.
This is used by auto completions to make sure that strings
are inserted verbatim and without unwanted sideeffects.
* All strings can now safely contain null-characters
(see also: 8-bit cleanliness).
The null-character itself (^@) is not (yet) a valid SciTECO
command, though.
An incomplete list of changes:
* We got rid of the BSD headers for RB trees and lists/queues.
The problem with them was that they used a form of metaprogramming
only to gain a bit of type safety. It also resulted in less
readble code. This was a C++ desease.
The new code avoids metaprogramming only to gain type safety.
The BSD tree.h has been replaced by rb3ptr by Jens Stimpfle
(https://github.com/jstimpfle/rb3ptr).
This implementation is also more memory efficient than BSD's.
The BSD list.h and queue.h has been replaced with a custom
src/list.h.
* Fixed crashes, performance issues and compatibility issues with
the Gtk 3 User Interface.
It is now more or less ready for general use.
The GDK lock is no longer used to avoid using deprecated functions.
On the downside, the new implementation (driving the Gtk event loop
stepwise) is even slower than the old one.
A few glitches remain (see TODO), but it is hoped that they will
be resolved by the Scintilla update which will be performed soon.
* A lot of program units have been split up, so they are shorter
and easier to maintain: core-commands.c, qreg-commands.c,
goto-commands.c, file-utils.h.
* Parser states are simply structs of callbacks now.
They still use a kind of polymorphy using a preprocessor trick.
TECO_DEFINE_STATE() takes an initializer list that will be
merged with the default list of field initializers.
To "subclass" states, you can simply define new macros that add
initializers to existing macros.
* Parsers no longer have a "transitions" table but the input_cb()
may use switch-case statements.
There are also teco_machine_main_transition_t now which can
be used to implement simple transitions. Additionally, you
can specify functions to execute during transitions.
This largely avoids long switch-case-statements.
* Parsers are embeddable/reusable now, at least in parse-only mode.
This does not currently bring any advantages but may later
be used to write a Scintilla lexer for TECO syntax highlighting.
Once parsers are fully embeddable, it will also be possible
to run TECO macros in a kind of coroutine which would allow
them to process string arguments in real time.
* undo.[ch] still uses metaprogramming extensively but via
the C preprocessor of course. On the downside, most undo
token generators must be initiated explicitly (theoretically
we could have used embedded functions / trampolines to
instantiate automatically but this has turned out to be
dangereous).
There is a TECO_DEFINE_UNDO_CALL() to generate closures for
arbitrary functions now (ie. to call an arbitrary function
at undo-time). This simplified a lot of code and is much
shorter than manually pushing undo tokens in many cases.
* Instead of the ridiculous C++ Curiously Recurring Template
Pattern to achieve static polymorphy for user interface
implementations, we now simply declare all functions to
implement in interface.h and link in the implementations.
This is possible since we no longer hace to define
interface subclasses (all state is static variables in
the interface's *.c files).
* Headers are now significantly shorter than in C++ since
we can often hide more of our "class" implementations.
* Memory counting is based on dlmalloc for most platforms now.
Unfortunately, there is no malloc implementation that
provides an efficient constant-time memory counter that
is guaranteed to decrease when freeing memory.
But since we use a defined malloc implementation now,
malloc_usable_size() can be used safely for tracking memory use.
malloc() replacement is very tricky on Windows, so we
use a poll thread on Windows. This can also be enabled
on other supported platforms using --disable-malloc-replacement.
All in all, I'm still not pleased with the state of memory
limiting. It is a mess.
* Error handling uses GError now. This has the advantage that
the GError codes can be reused once we support error catching
in the SciTECO language.
* Added a few more test suite cases.
* Haiku is no longer supported as builds are instable and
I did not manage to debug them - quite possibly Haiku bugs
were responsible.
* Glib v2.44 or later are now required.
The GTK UI requires Gtk+ v3.12 or later now.
The GtkFlowBox fallback and sciteco-wrapper workaround are
no longer required.
* We now extensively use the GCC/Clang-specific g_auto
feature (automatic deallocations when leaving the current
code block).
* Updated copyright to 2021.
SciTECO has been in continuous development, even though there
have been no commits since 2018.
* Since these changes are so significant, the target release has
been set to v2.0.
It is planned that beginning with v3.0, the language will be
kept stable.
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