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* Clear the buffer for STDIN after incant_write/incant_addendumRory Dudley2024-03-021-0/+6
| | | | | Clear the 'out' buffer after we have written STDOUT to the files specified after the Meter::Write or Meter::Addendum verse.
* Cleanup commentsRory Dudley2024-03-021-24/+0
| | | | | | | Remove commented code relating to error checks for the incant_io functions. The parser should detect if no files where specified for Meter::Read, Meter::Write, or Meter::Addendum, meaning that these checks are not necessary.
* Add file redirection capabilitiesRory Dudley2024-03-021-14/+337
| | | | | | | | | | | Added the following file redirection capabilies: - '<': Read input into STDIN - '>': Write STDOUT to file - '>>': Append STDOUT to file If no files are specified, this counts as a parser error, and so no code will be executed, even when used in combination with the string (';') meter. Currently, there is no way to redirect STDERR.
* Fix handling of SIGINTRory Dudley2024-02-291-2/+3
| | | | | | | | | | | | | | | Keep track of a new atomic variable: at_prompt, which is set to true just before blocking on io::stdin.read_line, and set to false just calling Poem::read. Additionally, for background tasks, there is a new ps macro called btask, which changes the process group of commands that are forked into the background, so that they don't receive SIGINT from the keyboard. Notes: Changing the process group on the Command is done via CommandExt. More details here: https://doc.rust-lang.org/std/os/unix/process/trait.CommandExt.html#tymethod.process_group
* Parser testspipesRory Dudley2024-02-291-0/+157
| | | | Added twelve different tests for the parser (Poem::read).
* Parsing poems from a fileRory Dudley2024-02-291-0/+22
| | | | | | Added a match statement in the main parser loop that pushes a new verse into the poem if a newline is found. This might happen if parsing a poem from a file.
* Add doc comments for incant_ functionsRory Dudley2024-02-281-0/+43
| | | | | Added documentation comments for the Meter::incant_ functions, describing how each function operates.
* Parser comments and error checkingRory Dudley2024-02-281-9/+22
| | | | | | | | | Added an index to keep track of what position each char is at in the loop. Added a more verbose error message, which prints out the column that the parse error was detected, as well as the glyph that threw the error. Added more comments to the '&', whitespace, and char match statements. Changed parser behavior, so that a ';' glyph without a stanza does not cause a parser error.
* Refactor status variables in Poem::read()Rory Dudley2024-02-281-28/+29
| | | | | | | Moved the 'couplet' and 'metered' variables into functions impl'd for Verse. This cuts down on the boilerplate in the parsing loop, and also makes it so that their match statements are only ran when needed, rather than being called at every iteration of the loop.
* Fix && behavior regressionrmerrRory Dudley2024-02-281-9/+9
| | | | | | Introduce a switch to break from recite() if the forked process returns a non-zero exit code. The one except to this, is when using semicolons, then we do not care if the previous command failed.
* Remove custom errors and fix background forkingRory Dudley2024-02-271-20/+40
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Removes the custom errors in src/recite/erro.rs, and replaces them with std::io::Errors throughout (recite(), incant_, macros). Fixed a bug with the way forking to the background is handled, where registering the signal handler in main for all processes would break couplets (i.e. pipes). Instead, this sets up a new signal handler each time a process is forked into the background. It uses a Vec<i32> to keep track of all the background processes. Notes: First off, there is some defunct code in the main repl loop, which is an example of killing zombie processes after each prompt. This should be removed, but I kept it in, just in case I go back to it for some reason. To be honest, I have no clue why this code works. In theory, I should have to remove the pid from the pids: Vec<i32> if waitpid returns a positive integer. However, when I tried this, it completely broke the program. ¯\_(ツ)_/¯ Also, it's worth noting that registering a signal handler with signal_hook::low_level::register, is somewhat costly, according to their docs. Given that this only occurs for background processes that are forked, however, I think it is acceptable. Finally, we never unregister the signal handler, so I'm not sure if that's still hanging out in memory somewhere or no.
* Cleanup recite(), custom errors, fixed forkingRory Dudley2024-02-261-111/+70
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | First off, moved the giant match statements out of recite(), and into macros in src/recite/ps.rs. There still needs to be two, since any verse using the 'couplet' meter will need to redirect its STDOUT. Now the recite() function returns a Result<(), Mishap>, which can be invoked when calling the incant_ functions. Custom errors were added in the form of 'Mishap''s. They are intended to be returned from the incant_ functions, in the event that something goes wrong with the Command::spawn() or Child::wait(). They each take a String, which should be the verb or stanza that was entered by the user. The incant_ functions separate the functionality of each type of meter from the recite() function. They return a Result<i32, Mishap>, where i32 is the exit code of the program that ran, and Mishap is a possible error. Before, the shell was cheating at forking a process to the background. It would actually spawn a thread to wait for that process to finish. Now, the program simply registers a handler for SIGCHLD, and uses libc's waitpid() function to reap the child process, and print some output to the user, indicating that it's finished. Notes: This was a huge patch which did some desperately needed cleanup of the recite() function. Moving forward, will need to add more documentation, and will probably scrap the custom errors, since this implementation is a little half-baked. It's worth looking into in the future, but we can probably live with io::Error's for the time being. Fixing forking was a pretty big deal, though. In Linux, and other u**x-like operating systems, parent processes need to reap their child processes, otherwise they become zombies. Previously, the dwvsh did this by spawning a separate thread to wait for child processes that were forked to the background. Now, we are registering a handle for SIGCHLD, which is a signal that gets sent to the parent when one of their children finishes, or is killed. Using waitpid(2), we can determine which process ended, and do something about it. In the case of a processes that was forked into the background, when it finished, waitpid(2) will return its PID. For foreground processes, it returns -1.
* Reorganization and commentsRory Dudley2024-02-221-0/+628
Broke out the structs for a poem into their own file: src/recite.rs. Also put the 'prefresh' function into it's own file: src/recite/path.rs. Commented most of the parser code (including structs and helper methods related to parsing (i.e. Verse, Stanza, Meter, Poem)). Renamed any instance of the 'paths' variable to 'path'. Notes: The biggest task now is to cleanup Poem::recite. It has a ton of bogus error messages, and (seemingly) redundant code.