Ask for a folder chosen in the project browser to be made readable, and say whether it was. Every other read here goes through a channel confined to directories Issie already has a reason to trust, and a folder just picked out of the browser is not yet one of them. Main decides, by looking at the folder itself rather than taking the renderer's word: it admits one that holds sheets or a project marker. False therefore means "no project there", not "refused".

Ask the user to choose a project, with a dialog window. Return the chosen folder, or None if the user exits without choosing one. A project IS a directory, so that is what the dialog asks for. It used to ask for the .dprj inside one, which meant navigating into the project, past its sheets greyed out by the filter, to select a file that is empty, says nothing, and is named after the folder the user was already standing in - and whose directory was then all that was kept. Asking for the folder also lets a project whose marker was lost or renamed be opened, which the filter made impossible even though loading a project never reads it.

ask for existing sheet paths

Ask the user to choose a folder, for a caller that knows what it wants one for. Return None if the user exits without choosing one.

Ask the user a new project path, with a dialog window. Return None if the user exits withouth selecting a path.

returns the list of backup files in descending chronological order.

Every immediate subdirectory of `path`, classified, for the browser to draw - or why the folder could not be listed. One level only: this lists a folder, it does not search a disk. A native folder picker draws every folder alike, so it cannot show which of them hold projects - which is the whole reason Issie draws this list itself. Deliberately NOT readSubdirectories and inspectFolder, which reach the operating system through the confined filesystem channel. The folder being browsed is by definition one the user has not opened yet, so every folder worth showing was refused: the dialog opened on the folder holding the last project and reported that the user's Documents did not exist. The browse channel in src/Main/Bridge.fs answers this one question without that confinement, and carries names and counts rather than the contents of anything.

If the component is a RAM update its contents based on its initialiser

Which combination of marker and sheets means what. The one place that rule lives: inspectFolder reads a folder to answer it, and the project browser is handed the same two facts by main without either of them having to agree about the meaning separately.

copy a sheet from some source path to a destination path

Copy a sheet from some source path to a destination path, giving every component, port and connection in it a fresh uuid so that it cannot clash with the sheet it was copied from. Falls back to a plain file copy if the source cannot be parsed.

Create new empty diagram file. Automatically add the .dgm suffix.

False rather than an exception for a path main will not let Issie see. Every caller treats this as a question about whether to go on, and a throw here would turn a refusal into a crash - but it is logged, because "the file is not there" and "you may not look" are different problems.

Interface function that can read old-style circuits (without wire vertices) as well as new circuits with vertices. Old circuits have an expansion parameter since new symbols are larger (in units) than old ones.

Update from old component types to new In addition do some sanity checks The standard way to add functionality to an existing component is to create a new component type, keeping the old type. Then on reading sheets from disk both new and old will be correctly read. This function will be called on load and will convert from the old type to the new one so that the rest of issie need only process new types, but compatibility with saved old types remains.

Return data for memory if it is linked to a ram. Return mem data if it is unlinked Error if the read fails ot the file parse fails.

What a directory is to Issie, and how many sheets are in it, from the one read of it. The count is free once the classification has looked at the file names anyway.

True when the path exists and is a directory. False for a file, and for a path that is not there at all, so it is safe to use as a filter before reading a directory's contents.

True when a path has no parent to go up to - a drive root, or the root of a share. dirName returns such a path unchanged, which is what the browser's Up control asks.

returns the sequence number and name of the most recent (highest sequence number) backup file

load all files in folderpath. Return Ok list of LoadStatus or a single Error.

load a component from its canvas and other elements

Modification time in milliseconds since the epoch, or None when the path is not there. Works on a directory as well as a file. NB a directory's time changes when an entry is added to it, removed from it or renamed - NOT when a file already in it is rewritten in place.

Show a directory in the platform's file manager. On Windows this launches explorer.exe rather than calling shell.openPath, because the folder window is created by the already-running explorer.exe, which has no right to take the foreground away from Issie - so shell.openPath opens it *behind* the app. A process launched by the foreground process does have that right and passes it on. Measured on Windows 11: through shell.openPath the window lands immediately below Issie and Issie keeps focus, through the spawn immediately above it and focused. Every other platform raises it already, and shell.openPath is the portable route there. onError is given a readable reason when the directory cannot be shown. On platforms other than Windows it is called asynchronously, since shell.openPath reports failure by resolving with a non-empty message rather than by rejecting - so saying nothing would make a failure look like success.

The empty file that marks a directory as an Issie project, named after the directory.

Why a project may not be called this, if it may not. One rule, in one place: the creation form asks it of every keystroke so that the user sees the objection while they can still act on it, and tryCreateFolder asks it as the last word. It used to be reachable only by breaking it, after the native dialog had been dismissed, in an error box that took the typing with it.

read file names from directory: returning [] on any error.

Parse one "address data" line of a .ram file, which may carry a comment. lineNo is the 1-based line number in the file, used only to say where an error is.

The locations defined by a .ram file, and the comments written against them. Locations with no comment are absent from the second map.

Parse the lines of a .ram file, reporting the first bad line. lines must be the file's lines as they are, blanks included, so that reported line numbers match the file.

The immediate subdirectories of a folder, as full paths. [] if it cannot be read. Deliberately not readdir: under .NET that is Directory.GetFiles, which lists files only, while node's readdirSync lists directories too. Anything looking for subfolders through readdir therefore works in the app and finds nothing under test - which is how this function came to exist. The directories come from the one readdir rather than from a stat of each entry, which is what this used to do: existsSync and lstatSync per name, paid on every FILE in the folder before discarding it. Listing C:\Windows\System32 took 244ms that way and takes 3ms this way - 4,885 entries, of which 4,687 were files answering a question nobody asked. Directory.GetDirectories never had the problem, so only the node side changes.

Asyncronously remove file. ignore if file does not exist

Save state to normal file. Automatically add the .dgm suffix. This version will not correctly deal with bigint numbers. See svaStateToFileNew If serialisation fails the existing file is left untouched and an Error returned.

Save state to file. Automatically add the .dgm suffix. This is the new version of the function that uses the new state format and copes with bigints However, it seems that it is not used??

Split a .ram file line into the part which defines a memory location and the comment written against it, if any. A comment runs from "//" to the end of the line.

Absolute path to the static asset directory. This used to be worked out here, three ways: __static in development, a bare "./resources/static" relative to the working directory for production on Windows and Linux, and __dirname/../../static for production on macOS. All three land on the same place as the main process's process.resourcesPath, and __static in particular is a webpack substitution that expands to an expression over `path` and `process` - so it could not survive contextIsolation even in principle. Main resolves it once now and sends the answer; see Bridge.staticDirectory.

absolute path to repo directory ./static NB this path is not fixed (even as relative path) between production and dev builds, so this must be used to access static assets. Empty under plain .NET - the tests - which have no Electron to ask and are given the directory they work on explicitly.

Make a directory if it is not there, saying why if that could not be done. Creating a directory can genuinely fail - a read-only or full disk, a permissions policy - and the callers here are all able to carry on without it.

Make a loadedComponent from the file read from filePath. Return the component, or an Error string.

The per-user, writable Issie directory. Anything Issie writes for the user - demo working copies, component libraries the user makes or imports - belongs here and NOT beside the installation. On macOS the app bundle is signed and notarised, so writing inside it invalidates the signature and Gatekeeper can then refuse to launch it. On Windows the installation is usually under Program Files, which needs administrator rights to write. Both fail only for installed users, never in a development build, which is exactly the kind of bug that ships.

Where a demo project is copied so that the user can edit it.

Where libraries the user makes or imports live. The libraries shipped with Issie are NOT copied here: they stay read-only under the installation, and are found there directly.

Write utf8 encoded data to file. Create file if it does not exist.