IMPORTANT: There currently are no guarantees regarding the stability of the EndBASIC language definition nor the API exposed by this crate. Expect them to change at any time (especially the Rust API). Version numbers will not adhere to semantic versioning until 1.0.0.

IMPORTANT: Similarly, there are no guarantees that old releases will be able to talk to the cloud service. If you use the web interface, this should not be a problem, but if you use local builds, please try to stay on the latest release for the time being.

STILL UNDER DEVELOPMENT; NOT RELEASED YET.

• Issue #153: Added support for labels and GOTO. At this point, label names must be prefixed with an @ sign to resolve parsing ambiguities with the : line delimiter.

• Modified the interpreter to parse the full program before executing it, which is a requirement for supporting GOTOs and features like DATA. As a side-effect of this change, any syntax errors now cause the interpreted program to not run at all, as opposed to before where the program would make progress until it hit the error.

• Fixed erratic insertion of newlines in existing text in the editor.

• Issue #113: Added line and column tracking to error messages for parsing and execution errors. Also cleaned up Rust Debug impls that leaked into error messages for nicer errors.

• Added support for the exponent (^) operator and the SQR function.

• Issue #114: Added transparent promotion from integers to doubles, and truncation (via rounding) from doubles to integers.

• Issue #114: Removed the DTOI and ITOD functions now that integers and doubles are automatically converted between them, and added the CINT and INT functions.

• Issue #114: Removed the MAXD/MAXI and MIND/MINI duality in favor of simpler MAX and MIN functions that can mix and match integers and doubles.

• Issue #114: Added support for doubles in FOR iteration, both to specify the loop range and the step.

• Changed the syntax of the MOUNT command to take advantage of the AS keyword as an argument separator and thus be of the form MOUNT target$ AS $drive_name$.

• Fixed PRINT so that, if the statement ends in a comma or in a semicolon, no newline character is printed. Useful to construct output lines in multiple steps and matches the behavior of other BASIC implementations.

• Issue #154: Added support for the DATA statement and the READ and RESTORE commands. Booleans, numbers, and strings are supported, but strings must be double-quoted (as opposed to other BASIC implementations where the double-quoting is optional).

• Added the ASC, CHR, and STR functions.

• Modified the HELP command to only accept a string as its argument, instead of also recognizing a bare word. The latter was only approximate and would cause confusion when typing something like HELP DATA, which would result in a parse error.

• Renamed DEL as KILL to match QuickBASIC and avoid confusion with a potential future DELETE command implementation.

• Rewrote the SDL console internals to use a separate thread that implements the SDL main loop. This might fix some rendering issues that have been previously observed with this implementation (or provide an easy way to fix them later if not).

• Fixed EXIT so that it works in the context of WHILE loops and so that no further expressions are evaluated in FOR and `IF statements.

• Issue #111: Added support to interrupt running programs via CTRL+C.

• Rewrote the execution interpreter to be based on an iterative loop over a simplified bytecode representation instead of walking over the AST.

• Added support for GOSUB and RETURN.

• Issue #121: Added support for catching errors via ON ERROR GOTO and ON ERROR RESUME NEXT, both of which are returned by a new ERRMSG function with the details of the error that was caught.

• Issue #155: Added support for "line numbers as labels", just like QuickBASIC does, which permits running the traditional 10 GOTO 10 program. Note, however, that these line numbers have nothing to do with the actual line numbers in the file and that's something I still would like to address somehow in the future. On this topic, also removed line numbers from the output of LIST.

• Changed the syntax to call argument-less functions, such as INKEY and PI, so that they do not accept (). This matches traditional BASIC implementations.

• Replaced the EXIT command with the END keyword.

• Added support for DO loops with optional UNTIL/WHILE pre- and post-guards and EXIT DO early terminations.

• Added support for uniline IF statements.

• Added support for SELECT CASE.

• Fixed INPUT so that the prompt is optional and thus things like INPUT var work as expected from traditional BASIC implementations.

• Extended AND, NOT, OR, and XOR to perform bitwise operations when operating on an integer context.

• Added syntax to specify integers in different bases, using forms like: &b_1010, &d_1234, &o_750, and &x_12f.

• Issue #108: Added the SCRROWS and SCRCOLS functions to query the size of the textual console and the GFX_HEIGHT and GFX_WIDTH for the graphical console.

• Added the GFX_CIRCLE and GFX_CIRCLEF commands to draw circles.

• Extended the builtin language documentation to explain in detail every statement type. HELP "LANG" now displays a collection of topics to choose from, instead of a one-page cheat sheet.

• Added the PALETTE.BAS demo, which is a little tool that renders the full color palette.

Released on 2022-06-05.

The primary goal of this release is to support major changes in the EndBASIC cloud service, which has a completely new account signup and authentication flow that allow unauthenticated users to load publicly shared files. These changes, combined with the in-interpreter account signup flow, fulfill the vision of the cloud service interactions.

Cloud service changes:

• Updated LOGIN to deal with the new version of the EndBASIC cloud service that does not use Azure AD for authentication. This new command is faster and simpler.

• Added the SIGNUP command to create cloud accounts right from the REPL. Having this command in the interpreter had always been the goal, but it was not possible to implement it due to Azure AD authentication flows.

• Added support to access files without logging in first. The cloud:// file system scheme can now be used before using LOGIN, and the DIR and LOAD commands will work on the mounted drive as long as there are public files within it.

• Added the LOGOUT command. As a side-effect of this, it is now possible to use LOGIN multiple times within the same interpreter session.

• Issue #131: Added support to auto-run programs from the cloud to the web UI: a URL of the form https://repl.endbasic.dev/?run=username/path will load the interpreter, fetch path owned by username and run it.

• Added support to auto-run programs from the cloud to the CLI, to mimic the changes done to the web UI. A path of the form cloud://username/path given to the command line interpreter will fetch path owned by username and run it. Due to various limitations, this is only available when the interpreter is launched with the --interactive flag.

• Parameterized the cloud service to talk to. In the CLI, the new --service-url allows overriding the default, and in the web, the staging site now points to the staging service.

Usability fixes:

• Issue #161: Fixed input methods (line input in the REPL and the full-screen text editor) to properly accept UTF-8.

• Issue #163: Fixed backspace handling in the the web and SDL consoles so that the previous character is not left behind the cursor. The problem was visible in the web UI where the semi-transparent cursor would show the previous letter.

Internal changes:

• Added a new endbasic-client crate to assimilate all of the funcionality and commands required to talk to the cloud service. This helps to keep the endbasic-std crate leaner dependencies-wise and facilitates configuring the client.

Released on 2022-01-29.

• Issue #136: Fixed handling of key presses on the web interface so that they don't interfere with browser shortcuts. This prevents Tab from stealing focus from the terminal, the arrow keys from doing strange things when "caret browsing" is enabled, and the slash key in Firefox from triggering a search on the page.

• Issue #148: Fixed interactive line edits so that moving up and down through history doesn't leave old characters behind when the cursor is in the middle of a line (not at the end).

• Replaced the use of Google Analytics in the web interface with EndTRACKER, my own experiment at site statistics. If you are curious, this service's code is a direct fork of EndBASIC's cloud service--hence the name.

Released on 2021-11-11.

The main purpose of this release is to bring you the new hybrid graphics/text console in the form of a feature preview. This feature brings EndBASIC closer to its original secret goal, which is to become a platform with which to write simple retro-looking games.

Please be aware that the new console is still quite rudimentary. There are many missing drawing primitives, and performance isn't great yet. Fixing these might require changes in the APIs so any code you write might need to be updated in the future. But, remember that the same is true for all of EndBASIC right now given its 0.x state.

This release lines up with the Handmade Seattle 2021 conference, during which it was first announced.

Graphics support and related console changes:

• Added a graphical console based on SDL2 behind a new optional sdl feature. This is to support graphics on all desktop platforms and has been confirmed to work on FreeBSD, Linux, macOS, and Windows.

• Added the GFX_LINE, GFX_PIXEL, GFX_RECT, GFX_RECTF, and GFX_SYNC graphics commands.

• Added the INKEY function. This is especially useful to implement event loops in graphical applications.

• Fixed LOCATE so that the first argument is the column number and the second argument is the row number. It should always have been this way (in fact, this is the syntax exposed by Locomotive BASIC), but this is now necessary to match the ordering of the coordinates in all graphics commands and avoid confusion.

• Modified console facilities (including PRINT and INPUT) so that they do not clear lines up to the right margin. I had originally added this as a feature so that changing the background color in the REPL caused all subsequent lines to be formatted consistently, but this prevented composing overlapping text (with or without graphics), which is a necessary thing to do when rendering UIs.

• Rewrote the web frontend from scratch to support graphics rendering. This implies that we do not use xterm.js any more and instead use a custom-built console implementation. Beware of new bugs.

• Issue #67: Keyboard input on Android should now work when using a soft keyboard. This isn't perfect due to limitations in the Android web APIs but should do the trick for simple uses.

General command changes:

• Extended the CLEAR and NEW commands so that they reset various properties of the machine, not just variables. This includes the state of the console, whose color and video syncing bit are reset, and the GPIO pins, which are set to their default state.

• Modified the RUN command to issue a CLEAR upfront. Maintaining the previous state of the machine was just too confusing and error-prone due to side-effects causing execution failures.

• Added the MIND, MINI, MAXD, and MAXI functions.

• Added the DEG and RAD trigonometric commands and the ATN, COS, PI, SIN, and TAN functions. These are often needed to render graphics.

Interactivity improvements:

• Added support for the Home, End, Page Up, and Page Down keys in the text editor.

• Made the Backspace and Tab keys aware of indentation in the editor.

• Added support for the Home and End keys in text input fields.

• Modified the storage commands to keep track of the currently-loaded program path so that the editor can display it, so that LOAD, EXIT, and NEW can warn about unsaved changes, and so that SAVE can reuse the current filename.

Internal changes:

• Refactored the endbasic-std crate to minimize optional features in library crates by moving the textual console into a new endbasic-terminal crate, the SDL console into a new endbasic-sdl crate, and the Raspberry Pi support into a new endbasic-rpi crate.

• Added a new endbasic-repl crate to assimilate all of the features and code that are specific to the REPL. This finally breaks the dependency of the endbasic-web crate on the endbasic CLI crate, which required optional features to work.

Released on 2021-07-03.

This is a huge release and its primary goal is to offer integration with the new EndBASIC cloud service. To reach that goal, this release adds disk drives, new commands specifically for cloud interaction, and comes with various usability improvements to make the whole experience better.

Support for disk drives:

• Added support for storage drives. All file commands now take a path to a file of the form DRIVE:/PATH where the drive part and the slash are optional. By default, three drives are available: MEMORY:, which is a trivial memory-backed drive; DEMOS:, which contains the read-only demo files; and LOCAL:, which points to local storage (either a local directory or to the web browser's local storage).

• Added the CD command to change the current drive and the PWD command to print the current location.

• Extended the DIR command to take an optional path to the directory to show.

• Added the MOUNT and UNMOUNT commands to inspect and manipulate the mounted drives. Note that this now allows users to mount arbitrary parts of the external file system within the EndBASIC namespace, when in theory it wasn't possible to escape the programs directory before. This is intentional, but if there is a need, we can put restrictions in place again.

• Renamed the --programs-dir flag to --local-drive and removed the special handling of the :memory: value. Instead, this can now take arbitrary URIs to refer to drive targets.

Support for the EndBASIC cloud service:

• Added the LOGIN command to authenticate against the EndBASIC service and to mount the user's own drive.

• Added a new cloud:// mount target scheme to specify the drives of other users.

• Added the SHARE command to set reader ACLs on files hosted in the EndBASIC service, allowing users to share files among themselves.

Usability improvements:

• Refactored the HELP command to only print a summary of topics by default. As part of this, topics can now be looked up using prefixes of their names.

• Made the output of HELP fit within the screen for easier readability instead of allowing long paragraphs to wrap at unpredictable points.

• Added input history tracking to the REPL interface.

Miscellaneous additions:

• Added the array functions LBOUND and UBOUND.

Released on 2021-02-19.

Summary: support for (multidimensional) arrays and support for GPIO on the Raspberry Pi.

New standard library features:

• Added basic support for GPIO via the new GPIO_SETUP, GPIO_CLEAR, GPIO_WRITE commands and the GPIO_READ function. These symbols are always available, but at the moment, they are only functional on the Raspberry Pi. Support for this platform must be enabled via the new rpi feature because the rppal dependency does not compile on all supported platforms.

• Added the SLEEP command to pause execution for a certain period of time.

• Readded the LIST command to dump the stored program to the console. This was removed in 0.3 with the addition of the full-screen text editor, but having quick access to the program's contents is useful to showcase both code and output at once.

• Modified INPUT so that it autodetects the target type of a variable when the variable is already defined, instead of assuming the integer type for unqualified variable references.

New command line features:

• Added the new demo program DEMO:GPIO.BAS to accompany the new support for GPIO.

New language features and bug fixes:

• Added support for the DIM statement to define variables and arrays.

• Added support for multidimensional arrays.

• Replaced END WHILE with WEND as the earlier BASICs did. We could probably support both, but for now, sticking to the simpler world of a different keyword per statement seems nicer (and this matches what the FOR/NEXT pair do).

• Fixed the expression parser to properly handle symbol names that appear immediately after a left parenthesis. This broke with the addition of function calls.

• Fixed the definition of variables so that their names cannot shadow existing functions.

• Refactored the internal representation of symbols (variables, arrays, functions, and commands) for a more uniform handling. As a side-effect, it is now an error to have two symbols of any kind with the same name.

Released on 2021-01-25.

• Fixed the dependencies of the endbasic crate so that cargo install works as documented.

Released on 2021-01-24.

This is primarily a quality-focused release. Most of the work since 0.4.0 has gone into fixing long-standing issues in the codebase (particularly around internal testability), but a lot of these have also had end-user impact.

New user-experience features:

• Added support to load an AUTOEXEC.BAS file at REPL startup time.

• Made file names in the web UI case-insensitive. Any pre-existing files will be renamed to have an all-uppercase name to support the new semantics.

• Added support for an in-memory store when running the REPL by specifying the --programs-dir=:memory: flag.

• Added support to run scripts as if they were run in the interactive REPL by passing the --interactive flag.

Bug fixes:

• Fixed the EXIT command so that it doesn't terminate the REPL when it is part of a script run via RUN.

• Made the web interface not restart the machine on an exit request (such as a call to EXIT) so that any state is not lost. It's too easy to hit Ctrl+C by mistake, for example.

Major internal API changes:

• Split the language and standard library into two separate crates: the existing endbasic-core continues to provide the language interpreter and the new endbasic-std provides the standard library.

• Added a public testutils module within the std crate to offer test utilities for consumers of the EndBASIC crates.

Released on 2020-12-25.

New user-experience features:

• Added support for built-in demo programs. These are loadable via the special read-only DEMO:*.BAS files.

• Added the DEMO:GUESS.BAS, DEMO:HELLO.BAS and DEMO:TOUR.BAS built-in demo programs.

New language features:

• Added simple FOR range loops with support for custom STEPs.

• Added support for calls to builtin functions within expressions.

• Added string manipulation functions: LEFT, LEN, LTRIM, MID, RIGHT and RTRIM.

• Added numerical functions: DTOI and ITOD.

• Added support to for random numbers via the RANDOMIZE command and the RND numerical function.

• Added support for double-precision floating point numbers (# type annotation). This feature is incomplete in many ways but is needed for random number generation. Notably, it is not possible to express some double values in the code (exponents, infinities, and NaNs), and there is no type promotion between integers and doubles. Use the new ITOD AND DTOI functions to convert between these two types.

Bug fixes:

• Fixed the expression parser to properly handle subtractions where the first operand is a negative number.

• Fixed the expression parser to detect and report unbalanced parenthesis.

Operational changes:

• Builds from HEAD are now pushed to a separate staging area to keep the official site pinned to the latest release. This is to make release numbers meaningful in the web context.

Released on 2020-11-29.

The highlight of this new release is a much improved interactive interface, as it gets rid of the line-oriented editor (which used meaningless line numbers) and replaces it with a full-screen interactive editor.

New features:

• Turned the EDIT command into an interactive full-screen text editor and removed the LIST and RENUM commands.

• Added the CLS, COLOR, and LOCATE commands for terminal manipulation.

• Added the DEL command to delete a saved program.

• Added a language cheat sheet via HELP LANG.

• Added a barebones web interface.

Notable bug fixes:

• Fixed arithmetic operators to capture overflow conditions.

• Fixed EXIT to accept 0 as the exit code.

Structural code changes:

• Split the language core (parser, interpreter, and command implementations) out of the endbasic crate and moved it to a separate endbasic-core crate. This is to ensure that the language components stay free from heavy dependencies that assume things about the environment (like terminal or file system access).

• Made the language interpreter async-compatible.

Released on 2020-11-29.

Broken build due to a bad merge from HEAD.

Released on 2020-05-07.

This is the first release with an interactive command-line interface (aka a REPL). You can start this by simply typing endbasic without any arguments. Once in it, the following features are now available:

• The HELP command to provide interactive information.

• The CLEAR command to wipe machine state (variables).

• The stored program manipulation commands EDIT, LIST, NEW, RENUM and RUN.

• The on-disk program manipulation commands DIR, LOAD and SAVE.

Similarly, this is the first release that supports a nicer command-line invocation experience, including flag parsing. As a result:

• Added the --help and --version flags to the command-line interface.

Finally, these are the changes to the core interpreter and language:

• Added support for : as a statement delimiter.

• Added support for _ in identifiers.

• Made INPUT recognize yes/no and y/n answers for boolean values on top of the already supported true/false values.

• Added the MOD operator to compute the remainder of an integer division.

• Made INPUT resilient to invalid boolean and integer answers by asking the user to input them again. The caller has no means of determining failure so we must do this (like other BASIC implementations do).

• Split the INPUT and PRINT builtin commands out of the language's core and into their own module. This keeps the interpreter free from side-effects if the caller so chooses, which makes it ideal for embedding.

Released on 2020-04-22.

• Initial release of the EndBASIC project.