While the waste stack and the playable card on top of the waste stack
are collectively referred to as the "waste", it's programatically nice
to separate them to enable 3-card-draw mode. In that mode, the playable
stack will contain 3 cards with a slight x-axis shift, while the waste
stack underneath will remain unshifted. So rather than introducing some
ugly logic to CardStack to handle this, it's more convenient to have a
separate stack on top of the waste stack.
This non-POSIX header is used in Linux/BSD systems for storing the
default termios settings. This lets us setup new TTYs' `m_termios.c_cc`
in a nicer way than using a magic string.
Bytes in the 0x80..0x9F range were treated as C1 control codes,
which prevented them from being parsed as UTF-8 bytes.
This caused some characters (like U+DF, encoded as 0xC3 0x9F)
from being recognized as printable characters.
Since we now store intermediate characters separately, the intermediates
should be checked for the presence of the '?' DEC private marker, not
the first parameter.
This commit replaces the former, hand-written parser with a new one that
can be generated automatically according to a state change diagram.
The new `EscapeSequenceParser` class provides a more ergonomic interface
to dealing with escape sequences. This interface has been inspired by
Alacritty's [vte library](https://github.com/alacritty/vte/).
I tried to avoid changing the application logic inside the `Terminal`
class. While this code has not been thoroughly tested, I can't find
regressions in the basic command line utilities or `vttest`.
`Terminal` now displays nicer debug messages when it encounters an
unknown escape sequence. Defensive programming and bounds checks have
been added where we access parameters, and as a result, we can now
endure 4-5 seconds of `cat /dev/urandom`. :D
We generate EscapeSequenceStateMachine.h when building the in-kernel
LibVT, and we assume that the file is already in place when the userland
library is being built. This will probably cause problems later on, but
I can't find a way to do it nicely.
This program turns a description of a state machine that takes its input
byte-by-byte into C++ code. The state machine is described in a custom
format as specified below:
```
// Comments are started by two slashes, and cause the rest of the line
// to be ignored
@name ExampleStateMachine // sets the name of the generated class
@namespace Test // sets the namespace (optional)
@begin Begin // sets the state the parser will start in
// The rest of the file contains one or more states and an optional
// @anywhere directive. Each of these is a curly bracket delimited set
// of state transitions. State transitions contain a selector, the
// literal "=>" and a (new_state, action) tuple. Examples:
// 0x0a => (Begin, PrintLine)
// [0x00..0x1f] => (_, Warn) // '_' means no change
// [0x41..0x5a] => (BeginWord, _) // '_' means no action
// Rules common to all states. These take precedence over rules in the
// specific states.
@anywhere {
0x0a => (Begin, PrintLine)
[0x00..0x1f] => (_, Warn)
}
Begin {
[0x41..0x5a] => (Word, _)
[0x61..0x7a] => (Word, _)
// For missing values, the transition (_, _) is implied
}
Word {
// The entry action is run when we transition to this state from a
// *different* state. @anywhere can't have this
@entry IncreaseWordCount
0x09 => (Begin, _)
0x20 => (Begin, _)
// The exit action is run before we transition to any *other* state
// from here. @anywhere can't have this
@exit EndOfWord
}
```
The generated code consists of a single class which takes a
`Function<Action, u8>` as a parameter in its constructor. This gets
called whenever an action is to be done. This is because some input
might not produce an action, but others might produce up to 3 (exit,
state transition, entry). The actions allow us to build a more
advanced parser over the simple state machine.
The sole public method, `void advance(u8)`, handles the input
byte-by-byte, managing the state changes and requesting the appropriate
Action from the handler.
Internally, the state transitions are resolved via a lookup table. This
is a bit wasteful for more complex state machines, therefore the
generator is designed to be easily extendable with a switch-based
resolver; only the private `lookup_state_transition` method needs to be
re-implemented.
My goal for this tool is to use it for implementing a standard-compliant
ANSI escape sequence parser for LibVT, as described on
<https://vt100.net/emu/dec_ansi_parser>
By constraining two implementations, the compiler will select the best
fitting one. All this will require is duplicating the implementation and
simplifying for the `void` case.
This constraining also informs both the caller and compiler by passing
the callback parameter types as part of the constraint
(e.g.: `IterationFunction<int>`).
Some `for_each` functions in LibELF only take functions which return
`void`. This is a minimal correctness check, as it removes one way for a
function to incompletely do something.
There seems to be a possible idiom where inside a lambda, a `return;` is
the same as `continue;` in a for-loop.
Previously, all sorts of weird stuff would happen when the editor was at
the last line of the terminal (or when the printed line would be at the
last line), this commit makes the editor scroll the terminal up before
trying to write to a row that doesn't actually exist (yet).
This fixes ^R search making a mess when initiated at the last line
(especially with multiline prompts).
This implements different blend modes in the SoftwareRasterizer by
first setting up the blend factors then rendering the pixels into a
temporary buffer and finally mixing the contents of the temporary buffer
with the contents of the backbuffer based on the blend factors.
When returning autocomplete suggestions, we now consider the scope of
the name that is being completed.
For example, when requested to complete an expression like
'MyNamespace::', we will only suggest things that are in the
'MyNamespace' namespace.
This commit also has some general refactoring of the autocomplete
logic.
After this commit, Parser::index_of_node_at will prefer to return nodes
with greater indices.
Since the parsing logic ensures that child nodes come after parent
nodes, this change makes this function return child nodes when possible.
Previously, declarations that are not available in the global
namespace, such as member functions of a class, would also appear in
the autocomplete suggestions list.
To fix this, we now only recurse into scopes of namespaces and classes
when fetching declarations if we want to retrieve all the available
declarations in the document (For the use of Locator & ClassView).
Regressed in 8a4cc735b9.
We stopped generating "process created" when enabling profiling,
which led to Profiler getting confused about the missing events.
