In addition:
- extract commmand now skips exported generics in runtime wrappers
- interp_consistent_test.go fixed for go1.18 and go1.19
- move minimal version of go compiler to go1.18
Note that this version is incompatible with go1.17 and before due
to the major changes in the stdlib go parser.
To be merged once go1.19 is officially released (not before).
Make use of fs.FS (new to go 1.16) to allow for reading source files from diverse filesystems (local, embed, custom).
* `Options` has a new field `SourcecodeFilesystem fs.FS` so users can supply their own read-only filesystem containing source code.
* Defaults to the local filesystems (via `RealFS` - a thin `os.Open` wrapper complying with `fs.FS`) so regular users should see no change in behaviour.
* When no filesystem is available (e.g. WASM, or if you want to embed files to retain single binary distribution) an alternative filesystem is preferable to using `Eval(string)` as that requires the stringy code to be a single file monolith instead of multiple files. By using an `fs.FS` we can use `EvalPath()` and gain the ability to handle multiple files and packages.
* You can make use of embed filesystems (https://pkg.go.dev/embed) and custom filesystems obeying the `fs.FS` interface (I use one for http served zip files when targeting wasm as there is no local filesystem on wasm). Tests can make use of `fstest.Map`.
* NOTE: This does NOT affect what the running yaegi code considers its local filesystem, this is only for the interpreter finding the source code.
See `example/fs/fs_test.go` for an example.
Fixes#1200.
Marc Vertes
Johnny